diff --git a/app/.env.example b/app/.env.example
index 2472366e..afe4dacf 100644
--- a/app/.env.example
+++ b/app/.env.example
@@ -25,6 +25,11 @@ ARC_RPC_URL=
 # Elysium: the public node (https://rpc.elysium.kinetiq.xyz, the chain default when unset) is shared; use Alchemy elysium-mainnet in production.
 ELYSIUM_RPC_URL=
 # BASE_B20_RPC_URL=https://base-rpc.publicnode.com
+# Bridge funding networks, read through /api/rpc only (balances, allowances, gas before a deposit). Unset, they use
+# ethereum-rpc.publicnode.com, arb1.arbitrum.io/rpc and mainnet.optimism.io; the same Alchemy key covers all three.
+# ETHEREUM_RPC_URL=
+# ARBITRUM_RPC_URL=
+# OPTIMISM_RPC_URL=
 
 # Postgres (schema in db/schema.sql; `npm run migrate` applies it idempotently)
 DATABASE_URL=postgres://localhost/openlaunch_dev
diff --git a/app/src/app/api/rpc/route.test.ts b/app/src/app/api/rpc/route.test.ts
index 4a50b677..34a1f193 100644
--- a/app/src/app/api/rpc/route.test.ts
+++ b/app/src/app/api/rpc/route.test.ts
@@ -203,6 +203,40 @@ test("Arc routing uses its configured server upstream with the same read-only al
   assert.equal(body[1].error.code, -32601);
 });
 
+test("bridge funding networks read through public nodes by default, a keyed URL when set, with the same allowlist", async (t) => {
+  const envs = ["ETHEREUM_RPC_URL", "ARBITRUM_RPC_URL", "OPTIMISM_RPC_URL"] as const;
+  const previous = Object.fromEntries(envs.map((name) => [name, process.env[name]]));
+  t.after(() => { for (const name of envs) { if (previous[name] === undefined) delete process.env[name]; else process.env[name] = previous[name]; } });
+  for (const name of envs) delete process.env[name];
+  const seen: unknown[] = [];
+  t.mock.method(globalThis, "fetch", async (input: unknown, init?: RequestInit) => {
+    seen.push(input);
+    const calls = upstreamBody(init);
+    assert.deepEqual(calls.map((r) => r.method), ["eth_getBalance"]);
+    return Response.json(calls.map((r) => result(r.id, "0x1")));
+  });
+  for (const chain of ["ethereum", "arbitrum", "optimism"]) {
+    const response = await POST(request([call(1, "eth_getBalance"), call(2, "eth_sendRawTransaction")], chain));
+    assert.equal(response.status, 200, chain);
+    const body = await response.json();
+    assert.deepEqual(body[0], result(1, "0x1"));
+    assert.equal(body[1].error.code, -32601, chain);
+  }
+  assert.deepEqual(seen, ["https://ethereum-rpc.publicnode.com", "https://arb1.arbitrum.io/rpc", "https://mainnet.optimism.io"]);
+  process.env.ARBITRUM_RPC_URL = "https://arb-rpc.example.test/private-test-key";
+  await POST(request([call(1, "eth_getBalance")], "arbitrum"));
+  assert.equal(seen.at(-1), "https://arb-rpc.example.test/private-test-key");
+});
+
+test("an unknown chain key is refused before any upstream call", async (t) => {
+  const upstream = t.mock.method(globalThis, "fetch", async () => Response.json(result(1)));
+  for (const chain of ["polygon", "mainnet", "__proto__", "constructor", "1", "ETHEREUM"]) {
+    const response = await POST(request(call(1, "eth_chainId"), chain));
+    assert.equal(response.status, 400, chain);
+  }
+  assert.equal(upstream.mock.callCount(), 0);
+});
+
 test("single allowed reads keep their response shape; empty and oversized batches are rejected", async (t) => {
   const upstream = t.mock.method(globalThis, "fetch", async () => Response.json(result(1)));
   const single = await POST(request(call(1, "eth_chainId")));
diff --git a/app/src/app/api/rpc/route.ts b/app/src/app/api/rpc/route.ts
index 547bd818..3a9ef8aa 100644
--- a/app/src/app/api/rpc/route.ts
+++ b/app/src/app/api/rpc/route.ts
@@ -3,6 +3,7 @@ import { b20RpcUrl, rpcUrl } from "@/lib/chain";
 import { responseHasB20Error } from "@/lib/launchpad/baseStocks";
 import { CHAINS, DEFAULT_CHAIN, isChainKey } from "@/lib/chainPublic";
 import { upstreamStatus } from "@/lib/rpc-proxy";
+import { bridgeFundingUpstream } from "@/lib/bridge/rpc";
 
 export const runtime = "nodejs";
 export const dynamic = "force-dynamic";
@@ -64,9 +65,10 @@ function safeJson(text: string): unknown {
 export async function POST(req: Request) {
   const c = new URL(req.url).searchParams.get("chain") ?? DEFAULT_CHAIN;
   // every chain: the same read allowlist and per-IP bucket, its own upstream (the keyed *_RPC_URL, else the chain's
-  // official public node) so browsers never hit a public RPC directly and the API key stays server-side
-  if (!isChainKey(c)) return NextResponse.json({ error: "bad chain" }, { status: 400 });
-  const upstream = rpcUrl(c) ?? CHAINS[c].rpcUrls.default.http[0];
+  // official public node) so browsers never hit a public RPC directly and the API key stays server-side. The bridge's
+  // funding networks (ethereum, arbitrum, optimism) are read here too: balances, allowances and gas before a deposit.
+  const upstream = isChainKey(c) ? (rpcUrl(c) ?? CHAINS[c].rpcUrls.default.http[0]) : bridgeFundingUpstream(c);
+  if (upstream === null) return NextResponse.json({ error: "bad chain" }, { status: 400 });
   if (!upstream) return NextResponse.json({ error: "rpc unconfigured" }, { status: 503 });
   const ip = (req.headers.get("fly-client-ip") || req.headers.get("x-forwarded-for") || "").split(",")[0].trim() || "0.0.0.0";
   if (!take(ip)) return NextResponse.json({ error: "rate limited" }, { status: 429, headers: { "retry-after": "2" } });
diff --git a/app/src/app/ui-review-bridge/BridgeReview.tsx b/app/src/app/ui-review-bridge/BridgeReview.tsx
index 419241a0..28e3ca2b 100644
--- a/app/src/app/ui-review-bridge/BridgeReview.tsx
+++ b/app/src/app/ui-review-bridge/BridgeReview.tsx
@@ -6,7 +6,7 @@ import { X } from "lucide-react";
 import { BridgeForm, Transfer } from "@/components/bridge/BridgeDialog";
 import type useBridge from "@/components/bridge/useBridge";
 import { formatUnits, parseEther, parseUnits, zeroAddress } from "viem";
-import { changeBridgeRoute, parseBridgeAmount, type BridgeRouteChange, type BridgeRouteInputs } from "@/lib/bridge/client";
+import { canReverseBridgeRoute, changeBridgeRoute, parseBridgeAmount, type BridgeRouteChange, type BridgeRouteInputs } from "@/lib/bridge/client";
 import { bridgeCurrency, bridgeFeePercent, defaultBridgeAsset, type BridgeQuote } from "@/lib/bridge/types";
 import type { TrackedApproval } from "@/lib/bridge/approval";
 import { describePendingApproval } from "@/lib/bridge/approval-health";
@@ -55,7 +55,7 @@ export default function BridgeReview() {
   const rejectedFee = scene === "fee_boundary" ? inputAmount / 20n + 1n : scene === "impact_limit" ? inputAmount / 400n : inputAmount * 55548n / 1_000_000n;
   const bridge: ReturnType<typeof useBridge> = {
     address: scene === "disconnected" ? undefined : wallet, walletChainId: origin,
-    originChainId: origin, destinationChainId: destination, setOriginChainId: (chainId) => changeRoute({ side: "origin", chainId }), setDestinationChainId: (chainId) => changeRoute({ side: "destination", chainId }), reverseRoute: () => changeRoute({ side: "reverse" }), amount, setAmount,
+    originChainId: origin, destinationChainId: destination, setOriginChainId: (chainId) => changeRoute({ side: "origin", chainId }), setDestinationChainId: (chainId) => changeRoute({ side: "destination", chainId }), reverseRoute: () => changeRoute({ side: "reverse" }), canReverse: canReverseBridgeRoute({ originChainId: origin }), amount, setAmount,
     originAsset, destinationAsset, setOriginAsset: (asset) => changeRoute({ side: "origin-asset", asset }), setDestinationAsset: (asset) => changeRoute({ side: "destination-asset", asset }),
     balance: parseUnits(originAsset === "USDC" ? "125" : "0.05", inputCurrency.decimals), nativeBalance: parseEther(origin === 5042 ? "125" : "0.05"), balanceLoading: false, balanceError: null,
     quote: scene === "quote" || scene === "expired" ? quote : null,
diff --git a/app/src/components/WalletMenu.tsx b/app/src/components/WalletMenu.tsx
index 2fe71b0c..1d1c63dc 100644
--- a/app/src/components/WalletMenu.tsx
+++ b/app/src/components/WalletMenu.tsx
@@ -5,7 +5,7 @@ import Image from "next/image";
 import { useRef, useState } from "react";
 import { Popover } from "@base-ui/react/popover";
 import { ArrowDownUp, ArrowRight, ArrowUpRight, Check, ChevronDown, Copy, LayoutDashboard, LogOut, X } from "lucide-react";
-import { CHAIN_LABELS, CHAIN_SHORT, chainKeyOf, explorerAddress, explorerName, shortAddr, type ChainKey } from "@/lib/chainPublic";
+import { CHAIN_LABELS, CHAIN_SHORT, chainKeyOf, explorerAddress, explorerName, isChainKey, shortAddr, type ChainKey } from "@/lib/chainPublic";
 import { BRIDGE_CHAINS, isBridgeChainId } from "@/lib/bridge/types";
 import { VISIBLE_CHAINS } from "@/lib/launchpad/config";
 import WalletAvatar from "./WalletAvatar";
@@ -37,8 +37,9 @@ function NetworkLogo({ chain }: { chain: ChainKey }) {
  * network the site doesn't support. The chip's name for it pushed the Launch button out of the header, so only the
  * mobile row spells it out.
  */
-function NetworkBadge({ chain }: { chain: ChainKey | null }) {
-  if (!chain) return <span className={styles.networkWarn} aria-hidden>!</span>;
+/** A launch chain shows its logo; a bridge funding network (Ethereum, Arbitrum, Optimism) shows none; anything else warns. */
+function NetworkBadge({ chain, known = false }: { chain: ChainKey | null; known?: boolean }) {
+  if (!chain) return known ? null : <span className={styles.networkWarn} aria-hidden>!</span>;
   return <ChainLogo chain={chain} size={14} className="absolute -right-1 -bottom-1 ring-2 ring-card" />;
 }
 
@@ -115,7 +116,7 @@ function AccountMenu({ address, chainId, connectorName, block = false, switching
         title={block ? undefined : key || bridgeNetwork ? `On ${network}` : "Unsupported network. Open to switch"}
         data-unsupported={(!key && !bridgeNetwork) || undefined}
       >
-        <span className={styles.triggerMark}><WalletAvatar address={address} />{block ? <span className={styles.connectionDot} /> : <NetworkBadge chain={key ?? bridgeNetwork?.key ?? null} />}</span>
+        <span className={styles.triggerMark}><WalletAvatar address={address} />{block ? <span className={styles.connectionDot} /> : <NetworkBadge chain={key ?? (bridgeNetwork && isChainKey(bridgeNetwork.key) ? bridgeNetwork.key : null)} known={!!bridgeNetwork} />}</span>
         <span className={styles.triggerAddress}>{shortAddr(address)}</span>
         {block ? <span className={styles.triggerNetwork}>{key || bridgeNetwork ? network : "Switch"}</span> : null}
         <ChevronDown size={13} className={styles.chevron} aria-hidden />
diff --git a/app/src/components/bridge/BridgeDialog.module.css b/app/src/components/bridge/BridgeDialog.module.css
index 69a78d6a..24f2156d 100644
--- a/app/src/components/bridge/BridgeDialog.module.css
+++ b/app/src/components/bridge/BridgeDialog.module.css
@@ -31,6 +31,11 @@
 .networkPopup ::selection { background: var(--color-brand-soft); color: var(--color-brand); }
 .networkMenuTitle { margin: 0; padding: 8px 10px 10px; color: var(--color-body); font-size: 12px; font-weight: 500; }
 .networkList { display: grid; gap: 3px; }
+.networkGroupLabel { margin: 0; padding: 12px 10px 6px; border-top: 1px solid var(--color-line); color: var(--color-muted); font-size: 12px; font-weight: 500; }
+.letterMark { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 50%; background: var(--mark-fill); box-shadow: 0 0 0 1.5px var(--mark-ring); color: #fff; font-size: 9px; font-weight: 700; letter-spacing: .02em; }
+.walletHint { display: block; width: 100%; margin-top: 12px; padding: 9px 12px; border: 1px dashed var(--color-line-strong); border-radius: 10px; color: var(--color-body); font-size: 12px; text-align: left; cursor: pointer; transition: color 160ms, background 160ms; }
+.walletHint:not(:disabled):hover { color: var(--color-ink); background: var(--color-paper); }
+.walletHint:disabled { cursor: default; opacity: .6; }
 .networkOption { display: grid; grid-template-columns: 30px minmax(0, 1fr) 20px; align-items: center; gap: 12px; min-height: 64px; padding: 10px; border-radius: 10px; cursor: pointer; outline: none; user-select: none; }
 .networkOption[data-highlighted] { background: var(--color-paper); box-shadow: inset 0 0 0 1px var(--color-line-strong); }
 .networkOption[data-selected] { background: var(--color-brand-soft); }
diff --git a/app/src/components/bridge/BridgeDialog.tsx b/app/src/components/bridge/BridgeDialog.tsx
index 9daa0717..aa742a77 100644
--- a/app/src/components/bridge/BridgeDialog.tsx
+++ b/app/src/components/bridge/BridgeDialog.tsx
@@ -6,7 +6,7 @@ import { Dialog } from "@base-ui/react/dialog";
 import { Select } from "@base-ui/react/select";
 import { ArrowLeftRight, ArrowRight, ArrowUpRight, Check, ChevronDown, ChevronRight, CircleAlert, CircleDollarSign, Clock3, LoaderCircle, Wallet, X } from "lucide-react";
 import { formatEther, formatUnits, zeroAddress } from "viem";
-import { BRIDGE_ASSETS, BRIDGE_ASSET_NAMES, BRIDGE_CHAINS, BRIDGE_CHAIN_IDS, bridgeCurrency, bridgeTokenAsset, bridgeTransferInputCurrency, isBridgeAssetSupported, isBridgeChainId, type BridgeAsset, type BridgeChainId, type BridgeQuoteRejection } from "@/lib/bridge/types";
+import { BRIDGE_ASSETS, BRIDGE_ASSET_NAMES, BRIDGE_CHAINS, BRIDGE_CHAIN_IDS, BRIDGE_DESTINATION_IDS, bridgeCurrency, bridgeTokenAsset, bridgeTransferInputCurrency, isBridgeAssetSupported, isBridgeChainId, isBridgeFundingChain, type BridgeAsset, type BridgeChainId, type BridgeQuoteRejection } from "@/lib/bridge/types";
 import { DISCARD_AFTER_MS } from "@/lib/bridge/client";
 import { formatFeeWarningPercent } from "@/lib/bridge/fee-display";
 import { shortAddr } from "@/lib/chainPublic";
@@ -16,7 +16,14 @@ import useBridge from "./useBridge";
 import styles from "./BridgeDialog.module.css";
 
 type Bridge = ReturnType<typeof useBridge>;
-const networkItems = BRIDGE_CHAIN_IDS.map((id) => ({ value: id, label: BRIDGE_CHAINS[id].name }));
+// Money leaves from any network, funding ones included, but arrives only on a launch chain.
+const SOURCE_CHAINS: readonly BridgeChainId[] = BRIDGE_CHAIN_IDS;
+const DESTINATION_CHAINS: readonly BridgeChainId[] = BRIDGE_DESTINATION_IDS;
+// Funding networks without a bundled logo get a lettermark in the network's own colours.
+const LETTERMARKS: Partial<Record<BridgeChainId, { text: string; fill: string; ring: string }>> = {
+  42161: { text: "ARB", fill: "#213147", ring: "#12aaff" },
+  10: { text: "OP", fill: "#ff0420", ring: "#ff0420" },
+};
 
 function nativeAmount(value: string | bigint): string {
   const text = typeof value === "bigint" ? formatEther(value) : value;
@@ -26,6 +33,9 @@ function nativeAmount(value: string | bigint): string {
 }
 
 function NetworkMark({ chain }: { chain: BridgeChainId }) {
+  const letters = LETTERMARKS[chain];
+  if (letters) return <span className={styles.networkMark} aria-hidden><span className={styles.letterMark} style={{ "--mark-fill": letters.fill, "--mark-ring": letters.ring } as React.CSSProperties}>{letters.text}</span></span>;
+  if (chain === 1) return <span className={styles.networkMark} aria-hidden><Image src="/brand/ethereum.svg" alt="" width={28} height={28} draggable={false} /></span>;
   return <span className={`${styles.networkMark} ${chain === 5042 ? styles.arcMark : ""}`} aria-hidden>{chain === 8453
     ? <Image src="/brand/base.svg" alt="" width={30} height={30} draggable={false} />
     : chain === 5042 ? <Image src="/brand/arc.svg" alt="" width={23} height={24} draggable={false} />
@@ -70,8 +80,19 @@ function AssetSelect({ label, chain, asset, disabled, onChange }: { label: "Send
 
 function NetworkSelect({ label, chain, disabled, onChange }: { label: "From" | "To"; chain: BridgeChainId; disabled: boolean; onChange: (chain: BridgeChainId) => void }) {
   const [instant, setInstant] = useState(false);
+  const chains = label === "From" ? SOURCE_CHAINS : DESTINATION_CHAINS;
+  const launch = chains.filter((id) => !isBridgeFundingChain(id));
+  const funding = chains.filter(isBridgeFundingChain);
+  const option = (id: BridgeChainId) => <Select.Item key={id} value={id} label={BRIDGE_CHAINS[id].name} className={styles.networkOption}>
+    <NetworkMark chain={id} />
+    <span className={styles.networkCopy}>
+      <Select.ItemText className={styles.networkName}>{BRIDGE_CHAINS[id].name}</Select.ItemText>
+      <span className={styles.gasCurrency}>{BRIDGE_CHAINS[id].symbol} · Gas token</span>
+    </span>
+    <Select.ItemIndicator className={styles.networkCheck}><Check size={17} strokeWidth={2.5} aria-hidden /></Select.ItemIndicator>
+  </Select.Item>;
   return <div className={styles.network}>
-    <Select.Root value={chain} items={networkItems} disabled={disabled}
+    <Select.Root value={chain} items={chains.map((id) => ({ value: id, label: BRIDGE_CHAINS[id].name }))} disabled={disabled}
       onValueChange={(value) => { if (isBridgeChainId(value)) onChange(value); }}
       onOpenChange={(_, details) => setInstant(details.event.type.startsWith("key"))}>
       <Select.Label className={styles.smallLabel}>{label}<span className="sr-only"> network</span></Select.Label>
@@ -88,14 +109,11 @@ function NetworkSelect({ label, chain, disabled, onChange }: { label: "From" | "
           <Select.Popup className={styles.networkPopup} data-instant={instant || undefined}>
             <p className={styles.networkMenuTitle}>{label === "From" ? "Send from" : "Receive on"}</p>
             <Select.List className={styles.networkList}>
-              {BRIDGE_CHAIN_IDS.map((id) => <Select.Item key={id} value={id} label={BRIDGE_CHAINS[id].name} className={styles.networkOption}>
-                <NetworkMark chain={id} />
-                <span className={styles.networkCopy}>
-                  <Select.ItemText className={styles.networkName}>{BRIDGE_CHAINS[id].name}</Select.ItemText>
-                  <span className={styles.gasCurrency}>{BRIDGE_CHAINS[id].symbol} · Gas token</span>
-                </span>
-                <Select.ItemIndicator className={styles.networkCheck}><Check size={17} strokeWidth={2.5} aria-hidden /></Select.ItemIndicator>
-              </Select.Item>)}
+              {launch.map(option)}
+              {funding.length > 0 ? <Select.Group className={styles.networkList}>
+                <Select.GroupLabel className={styles.networkGroupLabel}>Fund from</Select.GroupLabel>
+                {funding.map(option)}
+              </Select.Group> : null}
             </Select.List>
           </Select.Popup>
         </Select.Positioner>
@@ -191,6 +209,8 @@ export function BridgeForm({ bridge: b, connect }: { bridge: Bridge; connect: ()
   const outputCurrency = bridgeCurrency(b.destinationChainId, b.destinationAsset, "output");
   const erc20Input = inputCurrency.address !== zeroAddress;
   const convertsAsset = inputCurrency.symbol !== outputCurrency.symbol;
+  // a wallet sitting on a funding network most likely wants to send from it
+  const walletFunding = b.address && isBridgeFundingChain(b.walletChainId) && b.walletChainId !== b.originChainId ? b.walletChainId : null;
   const outputAmount = (value: string) => nativeAmount(formatUnits(BigInt(value), outputCurrency.decimals));
   const label = b.approvalBusy ? `Confirm ${inputCurrency.symbol} approval…` : b.allowanceLoading ? `Checking ${inputCurrency.symbol} permission…` : b.quoteLoading ? "Getting your quote…"
     : b.phase === "switching" ? "Confirm network switch…"
@@ -209,9 +229,10 @@ export function BridgeForm({ bridge: b, connect }: { bridge: Bridge; connect: ()
     }}>
       <div className={styles.route}>
         <NetworkSelect label="From" chain={b.originChainId} disabled={locked} onChange={b.setOriginChainId} />
-        <button type="button" className={styles.reverse} aria-label={`Reverse route: ${destination.name} to ${origin.name}`} disabled={locked} onClick={b.reverseRoute}><ArrowLeftRight size={18} aria-hidden /></button>
+        <button type="button" className={styles.reverse} aria-label={b.canReverse ? `Reverse route: ${destination.name} to ${origin.name}` : `${origin.name} only sends funds here`} title={b.canReverse ? undefined : `${origin.name} only sends funds here`} disabled={locked || !b.canReverse} onClick={b.reverseRoute}><ArrowLeftRight size={18} aria-hidden /></button>
         <NetworkSelect label="To" chain={b.destinationChainId} disabled={locked} onChange={b.setDestinationChainId} />
       </div>
+      {walletFunding !== null ? <button type="button" className={styles.walletHint} disabled={locked} onClick={() => b.setOriginChainId(walletFunding)}>Your wallet is on {BRIDGE_CHAINS[walletFunding].name}. Send from {BRIDGE_CHAINS[walletFunding].name}</button> : null}
       {convertsAsset ? <p className={styles.conversionNote}>{inputCurrency.symbol} <ArrowRight size={12} aria-hidden /> {outputCurrency.symbol}<span>Converted by Relay</span></p> : null}
       {b.originChainId === 4663 || b.destinationChainId === 4663 ? <p className={styles.routeNotice}>USDC on Robinhood is unavailable: its routes do not pass our current safety checks. ETH and USDG are available.</p> : null}
       {erc20Input && b.approval?.chainId === b.originChainId && b.approval.status === "confirmed" && !b.quote ? <p className={styles.approvalNotice} role="status">{inputCurrency.symbol} approval confirmed. Review a fresh quote before bridging. No funds have been bridged yet.</p> : null}
diff --git a/app/src/components/bridge/BridgeProvider.tsx b/app/src/components/bridge/BridgeProvider.tsx
index 7228a71c..5e35c041 100644
--- a/app/src/components/bridge/BridgeProvider.tsx
+++ b/app/src/components/bridge/BridgeProvider.tsx
@@ -39,7 +39,7 @@ export function useOpenBridge(): (() => void) | null {
 export function BridgeButton({ block = false, compact = false, onOpen }: { block?: boolean; compact?: boolean; onOpen?: () => void }) {
   const show = useContext(BridgeContext);
   return (
-    <button type="button" className={`${styles.trigger} ${block ? styles.blockTrigger : ""} ${compact && !block ? styles.compactTrigger : ""}`} aria-label="Bridge funds" aria-haspopup="dialog" title="Bridge between Base, Robinhood and Arc" onClick={() => { show?.(); onOpen?.(); }}>
+    <button type="button" className={`${styles.trigger} ${block ? styles.blockTrigger : ""} ${compact && !block ? styles.compactTrigger : ""}`} aria-label="Bridge funds" aria-haspopup="dialog" title="Bridge to Base, Robinhood and Arc, or fund them from Ethereum, Arbitrum and Optimism" onClick={() => { show?.(); onOpen?.(); }}>
       <ArrowLeftRight size={17} strokeWidth={1.8} aria-hidden />
       <span className={styles.triggerLabel}>Bridge</span>
       {block ? <span className={styles.triggerHint}>Base · Robinhood · Arc</span> : null}
diff --git a/app/src/components/bridge/bridge-ui.test.ts b/app/src/components/bridge/bridge-ui.test.ts
index b8d03b29..31f21dd8 100644
--- a/app/src/components/bridge/bridge-ui.test.ts
+++ b/app/src/components/bridge/bridge-ui.test.ts
@@ -62,8 +62,13 @@ test("both quote and transfer recipients expose the full address without hover",
   assert.match(css, /input, select, summary\):focus-visible/);
 });
 
-test("bridge selectors expose three networks and label cross-asset conversion and gas", () => {
-  assert.match(panel, /BRIDGE_CHAIN_IDS.map/);
+test("bridge selectors send from every network, receive only on launch chains, and label conversion and gas", () => {
+  assert.match(panel, /const SOURCE_CHAINS: readonly BridgeChainId\[\] = BRIDGE_CHAIN_IDS;/);
+  assert.match(panel, /const DESTINATION_CHAINS: readonly BridgeChainId\[\] = BRIDGE_DESTINATION_IDS;/);
+  assert.match(panel, /const chains = label === "From" \? SOURCE_CHAINS : DESTINATION_CHAINS;/);
+  assert.match(panel, /<Select.GroupLabel className=\{styles.networkGroupLabel\}>Fund from<\/Select.GroupLabel>/);
+  assert.match(panel, /disabled=\{locked \|\| !b.canReverse\} onClick=\{b.reverseRoute\}/);
+  assert.match(panel, /onClick=\{\(\) => b.setOriginChainId\(walletFunding\)\}/);
   assert.match(panel, /Select.Trigger[^>]+aria-label=\{`\$\{label\} network`\}/);
   assert.match(panel, /onChange=\{b.setDestinationChainId\}/);
   assert.match(panel, /onClick=\{b.reverseRoute\}/);
@@ -76,7 +81,7 @@ test("bridge selectors expose three networks and label cross-asset conversion an
 test("network pickers use themed Base UI lists without native browser menus", () => {
   assert.match(panel, /import \{ Select \} from "@base-ui\/react\/select"/);
   assert.doesNotMatch(panel, /<select\b|<option\b/);
-  assert.match(panel, /Select.Root value=\{chain\} items=\{networkItems\} disabled=\{disabled\}/);
+  assert.match(panel, /Select.Root value=\{chain\} items=\{chains.map\(\(id\) => \(\{ value: id, label: BRIDGE_CHAINS\[id\].name \}\)\)\} disabled=\{disabled\}/);
   assert.match(panel, /if \(isBridgeChainId\(value\)\) onChange\(value\)/);
   assert.match(panel, /Select.Portal/);
   assert.match(panel, /alignItemWithTrigger=\{false\}/);
diff --git a/app/src/components/bridge/useBridge.ts b/app/src/components/bridge/useBridge.ts
index 743a47a2..981e5e92 100644
--- a/app/src/components/bridge/useBridge.ts
+++ b/app/src/components/bridge/useBridge.ts
@@ -9,7 +9,7 @@ import { BRIDGE_WALLET_CHAINS } from "@/lib/bridge/chains";
 import { BRIDGE_CHAINS, bridgeCurrency, defaultBridgeAsset, isBridgeAssetSupported, isBridgeChainId, type BridgeAsset, type BridgeChainId, type BridgeQuote, type BridgeQuoteRejection } from "@/lib/bridge/types";
 import { parseBridgeQuoteRejection } from "@/lib/bridge/client";
 import { createBridgeQuoteSession } from "@/lib/bridge/quote-session";
-import { activityAfterWalletChange, anchorQuoteExpiry, bridgeErrorMessage, bridgeGasBudget, bridgeRequest, bridgeRequestKey, changeBridgeRoute, hasMatchingDepositEvent, isHash, isMatchingSourceDeposit, linkedTimeoutSignal, mergeBridgeStatus, nativeSourceAmount, RELAY_DEPOSITORY, replacementSourceHash, submitBridgeDeposit, transferCanDiscard, transferIsTerminal, transferPhase, validateBridgeQuote, validateBridgeStatus, type BridgeActivity, type BridgePhase, type BridgeRouteChange, type BridgeRouteInputs, type ProviderObservation, type TrackedBridgeTransfer } from "@/lib/bridge/client";
+import { activityAfterWalletChange, anchorQuoteExpiry, bridgeErrorMessage, bridgeGasBudget, bridgeRequest, bridgeRequestKey, canReverseBridgeRoute, changeBridgeRoute, hasMatchingDepositEvent, isHash, isMatchingSourceDeposit, linkedTimeoutSignal, mergeBridgeStatus, nativeSourceAmount, RELAY_DEPOSITORY, replacementSourceHash, submitBridgeDeposit, transferCanDiscard, transferIsTerminal, transferPhase, validateBridgeQuote, validateBridgeStatus, type BridgeActivity, type BridgePhase, type BridgeRouteChange, type BridgeRouteInputs, type ProviderObservation, type TrackedBridgeTransfer } from "@/lib/bridge/client";
 import { BRIDGE_STORAGE_PREFIX, createBridgeTransferStore } from "@/lib/bridge/client-storage";
 import { APPROVAL_STORAGE_PREFIX, approvalBlocksSubmission, approvalCanDiscard, canApplyApprovalPoll, createApprovalStore, reconcileApproval, recoverApprovalFromEvidence, submitExactApproval, validateApprovalMetadata, type ApprovalReceiptObservation } from "@/lib/bridge/approval";
 import { APPROVAL_HEALTH_UNAVAILABLE, readPendingApprovalHealth, type ApprovalHealth } from "@/lib/bridge/approval-health";
@@ -665,6 +665,7 @@ export function useBridge(open: boolean) {
   const phase: BridgePhase = sending && (activePhase === "switching" || activePhase === "confirming") ? activePhase : tracked ? transferPhase(tracked) : activePhase === "quoting" ? "quoting" : quote ? "review" : "idle";
   return {
     address, walletChainId, originChainId, destinationChainId, originAsset, destinationAsset, setOriginAsset, setDestinationAsset, setOriginChainId, setDestinationChainId, reverseRoute, amount, setAmount,
+    canReverse: canReverseBridgeRoute(route),
     balance: inputIsToken ? tokenBalance.data : sourceBalance.data?.value,
     nativeBalance: sourceBalance.data?.value,
     balanceLoading: !!address && (inputIsToken ? tokenBalance.isPending : sourceBalance.isPending),
diff --git a/app/src/components/wallet-menu.test.ts b/app/src/components/wallet-menu.test.ts
index 591f371e..056fcb91 100644
--- a/app/src/components/wallet-menu.test.ts
+++ b/app/src/components/wallet-menu.test.ts
@@ -79,10 +79,11 @@ test("the header chip carries its network as an avatar badge; only the mobile ro
   // the network's name in the desktop chip pushed the Launch button out of the header (up to 49px in the floating pill)
   const trigger = source.slice(source.indexOf("<Popover.Trigger"), source.indexOf("</Popover.Trigger>"));
   assert.match(trigger, /\{block \? <span className=\{styles\.triggerNetwork\}>/);
-  assert.match(trigger, /block \? <span className=\{styles\.connectionDot\} \/> : <NetworkBadge chain=\{key \?\? bridgeNetwork\?\.key \?\? null\} \/>/);
+  // a bridge funding network (Ethereum, Arbitrum, Optimism) is known, so it shows no warning, but has no launch-chain logo
+  assert.match(trigger, /block \? <span className=\{styles\.connectionDot\} \/> : <NetworkBadge chain=\{key \?\? \(bridgeNetwork && isChainKey\(bridgeNetwork\.key\) \? bridgeNetwork\.key : null\)\} known=\{!!bridgeNetwork\} \/>/);
   assert.match(trigger, /title=\{block \? undefined : [^\n]*"Unsupported network\. Open to switch"\}/);
   const badge = source.slice(source.indexOf("function NetworkBadge"), source.indexOf("type WalletMenuProps"));
-  assert.match(badge, /if \(!chain\) return <span className=\{styles\.networkWarn\} aria-hidden>!<\/span>/);
+  assert.match(badge, /if \(!chain\) return known \? null : <span className=\{styles\.networkWarn\} aria-hidden>!<\/span>/);
   // the site's chain tile (Arc's white mark needs its dark tile), as on token avatars
   assert.match(badge, /<ChainLogo chain=\{chain\} size=\{14\} className="absolute -right-1 -bottom-1 ring-2 ring-card" \/>/);
   assert.match(css, /\.networkWarn\s*\{[^}]*position: absolute[^}]*background: var\(--color-warm\)/);
diff --git a/app/src/lib/bridge/chains.ts b/app/src/lib/bridge/chains.ts
index 0516d178..fcd8e112 100644
--- a/app/src/lib/bridge/chains.ts
+++ b/app/src/lib/bridge/chains.ts
@@ -1,10 +1,22 @@
 import type { Chain } from "viem";
-import { CHAINS } from "../chainPublic";
-import type { BridgeChainId } from "./types";
+import { arbitrum, mainnet, optimism } from "viem/chains";
+import { CHAINS, SITE_URL } from "../chainPublic";
+import { BRIDGE_CHAINS, BRIDGE_FUNDING_IDS, type BridgeChainId } from "./types";
 
 /** Wallet chains by Relay's numeric id. Arc is a launch chain like the others (chainPublic.ts); one definition for both. */
 export const BRIDGE_WALLET_CHAINS: Record<BridgeChainId, Chain> = {
   8453: CHAINS.base,
   4663: CHAINS.robinhood,
   5042: CHAINS.arc,
+  1: mainnet,
+  42161: arbitrum,
+  10: optimism,
 };
+
+/** The funding networks the wallet config adds next to the launch chains, so a wallet can switch to them and send. */
+export const BRIDGE_FUNDING_WALLET_CHAINS: readonly Chain[] = BRIDGE_FUNDING_IDS.map((id) => BRIDGE_WALLET_CHAINS[id]);
+
+/** Browser reads on a funding network go through the same-origin RPC proxy, like the launch chains (api/rpc). */
+export function bridgeFundingRpc(id: (typeof BRIDGE_FUNDING_IDS)[number]): string {
+  return `${SITE_URL}/api/rpc?chain=${BRIDGE_CHAINS[id].key}`;
+}
diff --git a/app/src/lib/bridge/client-chains.test.ts b/app/src/lib/bridge/client-chains.test.ts
index c88fbbd4..3a67f9bc 100644
--- a/app/src/lib/bridge/client-chains.test.ts
+++ b/app/src/lib/bridge/client-chains.test.ts
@@ -1,8 +1,8 @@
 import assert from "node:assert/strict";
 import { readFileSync } from "node:fs";
 import test from "node:test";
-import { CHAINS, CHAIN_KEYS } from "../chainPublic";
-import { BRIDGE_WALLET_CHAINS } from "./chains";
+import { CHAINS, CHAIN_KEYS, SITE_URL } from "../chainPublic";
+import { BRIDGE_FUNDING_WALLET_CHAINS, BRIDGE_WALLET_CHAINS, bridgeFundingRpc } from "./chains";
 import { BRIDGE_CHAIN_IDS, BRIDGE_CHAINS } from "./types";
 
 test("every bridge source has a matching wallet chain, and Arc is the registry's own chain", () => {
@@ -23,11 +23,17 @@ test("every bridge source has a matching wallet chain, and Arc is the registry's
   assert.notEqual(arc.id, 5042002);
 });
 
-test("wallet config registers Arc for switching and native-balance reads", () => {
+test("wallet config registers Arc and the funding networks for switching and native-balance reads", () => {
   const config = readFileSync(new URL("../wagmi.ts", import.meta.url), "utf8");
-  // every registry chain, Arc included, through the same proxied transport; the chain's own rpcUrls stay official for wallet_addEthereumChain
-  assert.match(config, /const chains = keys\.map\(\(k\) => CHAINS\[k\]\)/);
-  assert.match(config, /transports: Object\.fromEntries\(keys\.map\(\(k\) => \[CHAINS\[k\]\.id, http\(browserRpc\(k\)/);
+  // every registry chain, Arc included, then the bridge's funding networks, all through the same-origin proxy; the
+  // chains' own rpcUrls stay official for wallet_addEthereumChain
+  assert.match(config, /const chains = \[\.\.\.keys\.map\(\(k\) => CHAINS\[k\]\), \.\.\.BRIDGE_FUNDING_WALLET_CHAINS\]/);
+  assert.match(config, /\.\.\.keys\.map\(\(k\) => \[CHAINS\[k\]\.id, http\(browserRpc\(k\), \{ batch: true \}\)\]\)/);
+  assert.match(config, /\.\.\.BRIDGE_FUNDING_IDS\.map\(\(id\) => \[id, http\(bridgeFundingRpc\(id\), \{ batch: true \}\)\]\)/);
+  assert.equal(bridgeFundingRpc(1), `${SITE_URL}/api/rpc?chain=ethereum`);
+  assert.equal(bridgeFundingRpc(42161), `${SITE_URL}/api/rpc?chain=arbitrum`);
+  assert.equal(bridgeFundingRpc(10), `${SITE_URL}/api/rpc?chain=optimism`);
+  assert.deepEqual(BRIDGE_FUNDING_WALLET_CHAINS.map((chain) => chain.id), [1, 42161, 10]);
   assert.doesNotMatch(config, /rpc\.mainnet\.arc\.io/);
   const hook = readFileSync(new URL("../../components/bridge/useBridge.ts", import.meta.url), "utf8");
   assert.match(hook, /chain:\s*BRIDGE_WALLET_CHAINS\[q\.originChainId\]/);
diff --git a/app/src/lib/bridge/client.test.ts b/app/src/lib/bridge/client.test.ts
index dbfdea57..fd480bcc 100644
--- a/app/src/lib/bridge/client.test.ts
+++ b/app/src/lib/bridge/client.test.ts
@@ -1,10 +1,10 @@
 import assert from "node:assert/strict";
 import test from "node:test";
 import { encodeAbiParameters, encodeEventTopics, encodeFunctionData, HttpRequestError, InsufficientFundsError, RpcRequestError, SwitchChainError, UnknownRpcError, UserRejectedRequestError, type Address, type Hex } from "viem";
-import { activityAfterWalletChange, anchorQuoteExpiry, bridgeErrorMessage, DISCARD_AFTER_MS, linkedTimeoutSignal, replacementSourceHash, transferCanDiscard, bridgeGasBudget, bridgeRequest, bridgeRequestKey, changeBridgeRoute, ERC20_DEPOSIT_ABI, ERC20_DEPOSIT_EVENT, hasMatchingDepositEvent, isMatchingSourceDeposit, isWalletRejection, mergeBridgeStatus, nativeSourceAmount, NATIVE_DEPOSIT_ABI, NATIVE_DEPOSIT_EVENT, parseBridgeAmount, parseStoredTransfer, RELAY_DEPOSITORY, serializeTransfer, submitBridgeDeposit, transferIsTerminal, validateBridgeQuote, validateBridgeStatus, type DepositDependencies, type TrackedBridgeTransfer } from "./client";
+import { activityAfterWalletChange, anchorQuoteExpiry, bridgeErrorMessage, canReverseBridgeRoute, DISCARD_AFTER_MS, linkedTimeoutSignal, replacementSourceHash, transferCanDiscard, bridgeGasBudget, bridgeRequest, bridgeRequestKey, changeBridgeRoute, ERC20_DEPOSIT_ABI, ERC20_DEPOSIT_EVENT, hasMatchingDepositEvent, isMatchingSourceDeposit, isWalletRejection, mergeBridgeStatus, nativeSourceAmount, NATIVE_DEPOSIT_ABI, NATIVE_DEPOSIT_EVENT, parseBridgeAmount, parseStoredTransfer, RELAY_DEPOSITORY, serializeTransfer, submitBridgeDeposit, transferIsTerminal, validateBridgeQuote, validateBridgeStatus, type DepositDependencies, type TrackedBridgeTransfer } from "./client";
 import { bridgeStorageKey, createBridgeTransferStore } from "./client-storage";
 import { parseBridgeQuoteRejection } from "./client";
-import { ARC_USDC, BASE_USDC, BRIDGE_CHAIN_IDS, type BridgeQuote, type BridgeQuoteRejection, type BridgeQuoteRequest } from "./types";
+import { ARC_USDC, BASE_USDC, BRIDGE_CHAIN_IDS, BRIDGE_DESTINATION_IDS, BRIDGE_FUNDING_IDS, isBridgeFundingChain, type BridgeQuote, type BridgeQuoteRejection, type BridgeQuoteRequest } from "./types";
 
 const ADDRESS = "0x1111111111111111111111111111111111111111" as Address;
 const OTHER = "0x2222222222222222222222222222222222222222" as Address;
@@ -66,10 +66,10 @@ test("amount parsing preserves integer precision and never rounds extra decimal
   assert.equal(bridgeRequestKey(bridgeRequest(ADDRESS, 8453, "0.01", 4663)), bridgeRequestKey(bridgeRequest(ADDRESS, 8453, ".0100", 4663)));
 });
 
-test("all six routes use the input currency precision, never native decimals for Arc ERC20", () => {
+test("every route uses the input currency precision, never native decimals for Arc ERC20, and never ends on a funding network", () => {
   for (const origin of BRIDGE_CHAIN_IDS) for (const destination of BRIDGE_CHAIN_IDS) {
     const request = bridgeRequest(ADDRESS, origin, origin === 5042 ? "1.000001" : "1.000000000000000001", destination);
-    if (origin === destination) assert.equal(request, null);
+    if (origin === destination || isBridgeFundingChain(destination)) assert.equal(request, null);
     else {
       assert.equal(request?.amount, origin === 5042 ? "1000001" : "1000000000000000001");
       assert.equal(request?.destinationChainId, destination);
@@ -82,6 +82,27 @@ test("all six routes use the input currency precision, never native decimals for
   assert.notEqual(bridgeRequestKey(bridgeRequest(ADDRESS, 8453, "1", 4663)), bridgeRequestKey(bridgeRequest(ADDRESS, 8453, "1", 5042)));
 });
 
+test("funding networks send but never receive: no reverse, no destination, and a collision picks another launch chain", () => {
+  const fromArbitrum = { originChainId: 42161, destinationChainId: 8453, originAsset: "USDC", destinationAsset: "USDC", amount: "25" } as const;
+  assert.equal(canReverseBridgeRoute(fromArbitrum), false);
+  assert.deepEqual(changeBridgeRoute(fromArbitrum, { side: "reverse" }), fromArbitrum);
+  for (const id of BRIDGE_FUNDING_IDS) assert.deepEqual(changeBridgeRoute({ ...fromArbitrum, originChainId: 8453, destinationChainId: 4663 }, { side: "destination", chainId: id }), { ...fromArbitrum, originChainId: 8453, destinationChainId: 4663 });
+  // choosing the destination as the source cannot swap a funding network into the destination
+  assert.deepEqual(changeBridgeRoute(fromArbitrum, { side: "origin", chainId: 8453 }), { originChainId: 8453, destinationChainId: 4663, originAsset: "USDC", destinationAsset: "USDG", amount: "25" });
+  assert.deepEqual(changeBridgeRoute({ ...fromArbitrum, destinationChainId: 4663, destinationAsset: "USDG" }, { side: "origin", chainId: 4663 }), { originChainId: 4663, destinationChainId: 8453, originAsset: "USDG", destinationAsset: "USDC", amount: "" });
+  // moving between funding networks keeps the dollar and the amount
+  assert.deepEqual(changeBridgeRoute(fromArbitrum, { side: "origin", chainId: 10 }), { ...fromArbitrum, originChainId: 10 });
+  assert.deepEqual(changeBridgeRoute(fromArbitrum, { side: "origin", chainId: 1 }), { ...fromArbitrum, originChainId: 1 });
+  // and a launch chain still reverses
+  for (const id of BRIDGE_DESTINATION_IDS) assert.equal(canReverseBridgeRoute({ originChainId: id }), true);
+  for (const origin of BRIDGE_FUNDING_IDS) for (const destination of BRIDGE_DESTINATION_IDS) {
+    const usdc = bridgeRequest(ADDRESS, origin, "10.5", destination, "USDC", destination === 4663 ? "USDG" : "USDC");
+    assert.equal(usdc?.amount, "10500000");
+    const eth = bridgeRequest(ADDRESS, origin, "0.01", destination, "ETH", destination === 5042 ? "USDC" : "ETH");
+    assert.equal(eth?.amount, "10000000000000000");
+  }
+});
+
 test("network selections resolve collisions atomically and never reinterpret ETH amounts as USDC", () => {
   const initial = { originChainId: 8453, destinationChainId: 4663, amount: "0.01" } as const;
   const toArc = changeBridgeRoute(initial, { side: "destination", chainId: 5042 });
@@ -504,7 +525,9 @@ test("version-one recovery keeps old Base/Robinhood records and accepts every di
   for (const originChainId of BRIDGE_CHAIN_IDS) for (const destinationChainId of BRIDGE_CHAIN_IDS) {
     if (originChainId === destinationChainId) continue;
     const transfer = { ...tracked(), originChainId, destinationChainId };
-    assert.deepEqual(parseStoredTransfer(serializeTransfer(transfer), ADDRESS), { ...transfer, sourceHash: undefined });
+    // nothing is ever sent to a funding network, so a saved transfer naming one as its destination is corrupt
+    if (isBridgeFundingChain(destinationChainId)) assert.throws(() => parseStoredTransfer(serializeTransfer(transfer), ADDRESS));
+    else assert.deepEqual(parseStoredTransfer(serializeTransfer(transfer), ADDRESS), { ...transfer, sourceHash: undefined });
   }
 });
 
diff --git a/app/src/lib/bridge/client.ts b/app/src/lib/bridge/client.ts
index 41c81894..f43383d9 100644
--- a/app/src/lib/bridge/client.ts
+++ b/app/src/lib/bridge/client.ts
@@ -1,6 +1,6 @@
 import { BaseError, decodeEventLog, decodeFunctionData, encodeFunctionData, InsufficientFundsError, isAddress, parseUnits, type Address, type Hex } from "viem";
 import { friendlyError } from "../errors";
-import { BRIDGE_ASSETS, bridgeCurrency, bridgeFeePercent, defaultBridgeAsset, isBridgeAssetSupported, isBridgeChainId, isDollarAsset, type BridgeAsset, type BridgeChainId, type BridgeQuote, type BridgeQuoteRejection, type BridgeQuoteRequest, type BridgeStatus, type BridgeStatusResponse } from "./types";
+import { BRIDGE_ASSETS, BRIDGE_DESTINATION_IDS, bridgeCurrency, bridgeFeePercent, defaultBridgeAsset, isBridgeAssetSupported, isBridgeChainId, isBridgeDestination, isDollarAsset, type BridgeAsset, type BridgeChainId, type BridgeQuote, type BridgeQuoteRejection, type BridgeQuoteRequest, type BridgeStatus, type BridgeStatusResponse } from "./types";
 
 export type BridgePhase = "idle" | "quoting" | "review" | "switching" | "confirming" | "pending" | "success" | "refund" | "failure" | "uncertain";
 export type TrackedBridgeTransfer = BridgeQuoteRequest & {
@@ -47,7 +47,7 @@ export function parseBridgeAmount(value: string, decimals: 6 | 18 = 18): bigint
 }
 
 export function bridgeRequest(address: Address | undefined, originChainId: BridgeChainId, amount: string, destinationChainId: BridgeChainId, originAsset?: BridgeAsset, destinationAsset?: BridgeAsset): BridgeQuoteRequest | null {
-  if (!address || !isAddress(address) || !isBridgeChainId(originChainId) || !isBridgeChainId(destinationChainId) || originChainId === destinationChainId || !isBridgeAssetSupported(originChainId, originAsset ?? defaultBridgeAsset(originChainId)) || !isBridgeAssetSupported(destinationChainId, destinationAsset ?? defaultBridgeAsset(destinationChainId))) return null;
+  if (!address || !isAddress(address) || !isBridgeChainId(originChainId) || !isBridgeDestination(destinationChainId) || originChainId === destinationChainId || !isBridgeAssetSupported(originChainId, originAsset ?? defaultBridgeAsset(originChainId)) || !isBridgeAssetSupported(destinationChainId, destinationAsset ?? defaultBridgeAsset(destinationChainId))) return null;
   const units = parseBridgeAmount(amount, bridgeCurrency(originChainId, originAsset, "input").decimals);
   return units === null ? null : { address, originChainId, destinationChainId, amount: units.toString(), ...(originAsset ? { originAsset } : {}), ...(destinationAsset ? { destinationAsset } : {}) };
 }
@@ -55,6 +55,11 @@ export function bridgeRequest(address: Address | undefined, originChainId: Bridg
 export type BridgeRouteInputs = { originChainId: BridgeChainId; destinationChainId: BridgeChainId; amount: string; originAsset?: BridgeAsset; destinationAsset?: BridgeAsset };
 export type BridgeRouteChange = { side: "origin" | "destination"; chainId: BridgeChainId } | { side: "origin-asset" | "destination-asset"; asset: BridgeAsset } | { side: "reverse" };
 
+/** A route reverses only when its source can also receive: a funding network (Ethereum, Arbitrum, Optimism) cannot. */
+export function canReverseBridgeRoute(route: Pick<BridgeRouteInputs, "originChainId">): boolean {
+  return isBridgeDestination(route.originChainId);
+}
+
 /** Select/swap one distinct pair, clearing currency amounts when the source asset changes. */
 export function changeBridgeRoute(current: BridgeRouteInputs, change: BridgeRouteChange): BridgeRouteInputs {
   let { originChainId, destinationChainId } = current;
@@ -63,6 +68,7 @@ export function changeBridgeRoute(current: BridgeRouteInputs, change: BridgeRout
   const previousOriginAsset = originAsset;
   const explicitAssets = current.originAsset !== undefined || current.destinationAsset !== undefined || change.side === "origin-asset" || change.side === "destination-asset";
   if (change.side === "reverse") {
+    if (!canReverseBridgeRoute(current)) return current;
     [originChainId, destinationChainId] = [destinationChainId, originChainId];
     [originAsset, destinationAsset] = [destinationAsset, originAsset];
   } else if (change.side === "origin-asset" || change.side === "destination-asset") {
@@ -73,9 +79,15 @@ export function changeBridgeRoute(current: BridgeRouteInputs, change: BridgeRout
   } else if ("chainId" in change) {
     if (!isBridgeChainId(change.chainId)) return current;
     if (change.side === "origin") {
-      if (change.chainId === destinationChainId) { destinationChainId = originChainId; [originAsset, destinationAsset] = [destinationAsset, originAsset]; }
+      // picking the destination as the source swaps the ends, unless the old source is a funding network, which cannot
+      // receive: then the transfer goes to the first other launch chain
+      if (change.chainId === destinationChainId) {
+        if (isBridgeDestination(originChainId)) { destinationChainId = originChainId; [originAsset, destinationAsset] = [destinationAsset, originAsset]; }
+        else destinationChainId = BRIDGE_DESTINATION_IDS.find((id) => id !== change.chainId)!;
+      }
       originChainId = change.chainId;
     } else {
+      if (!isBridgeDestination(change.chainId)) return current;
       if (change.chainId === originChainId) { originChainId = destinationChainId; [originAsset, destinationAsset] = [destinationAsset, originAsset]; }
       destinationChainId = change.chainId;
     }
@@ -115,7 +127,7 @@ export function parseBridgeQuoteRejection(value: unknown, request: BridgeQuoteRe
     if (!value || typeof value !== "object" || Array.isArray(value)) return null;
     const rejected = value as BridgeQuoteRejection;
     const allowed = ["address", "originChainId", "destinationChainId", "originAsset", "destinationAsset", "amount", "reason", "relayFee", "relayFeePercent", "sourceGas", "totalImpactPercent"];
-    if (Object.keys(value).some((key) => !allowed.includes(key)) || !isAddress(rejected.address ?? "") || !isBridgeChainId(rejected.originChainId) || !isBridgeChainId(rejected.destinationChainId) || rejected.originChainId === rejected.destinationChainId || !isWei(rejected.amount, true)) return null;
+    if (Object.keys(value).some((key) => !allowed.includes(key)) || !isAddress(rejected.address ?? "") || !isBridgeChainId(rejected.originChainId) || !isBridgeDestination(rejected.destinationChainId) || rejected.originChainId === rejected.destinationChainId || !isWei(rejected.amount, true)) return null;
     if ((rejected.originAsset !== undefined && !isBridgeAssetSupported(rejected.originChainId, rejected.originAsset)) || (rejected.destinationAsset !== undefined && !isBridgeAssetSupported(rejected.destinationChainId, rejected.destinationAsset)) || bridgeRequestKey(rejected) !== bridgeRequestKey(request)) return null;
     const decimals = bridgeCurrency(rejected.originChainId, rejected.originAsset, "input").decimals;
     for (const [fee, precision] of [[rejected.relayFee, decimals], [rejected.sourceGas, 18]] as const) {
@@ -134,7 +146,7 @@ export function parseBridgeQuoteRejection(value: unknown, request: BridgeQuoteRe
 export function validateBridgeQuote(value: unknown, request: BridgeQuoteRequest, now: number): BridgeQuote {
   if (!value || typeof value !== "object") throw new Error("The bridge returned an invalid quote. Request a new quote.");
   const quote = value as BridgeQuote;
-  if (!isAddress(quote.address ?? "") || !isBridgeChainId(quote.originChainId) || !isBridgeChainId(quote.destinationChainId) || !isBridgeAssetSupported(quote.originChainId, quote.originAsset ?? defaultBridgeAsset(quote.originChainId)) || !isBridgeAssetSupported(quote.destinationChainId, quote.destinationAsset ?? defaultBridgeAsset(quote.destinationChainId)) || bridgeRequestKey(quote) !== bridgeRequestKey(request) || quote.destinationChainId === quote.originChainId) {
+  if (!isAddress(quote.address ?? "") || !isBridgeChainId(quote.originChainId) || !isBridgeDestination(quote.destinationChainId) || !isBridgeAssetSupported(quote.originChainId, quote.originAsset ?? defaultBridgeAsset(quote.originChainId)) || !isBridgeAssetSupported(quote.destinationChainId, quote.destinationAsset ?? defaultBridgeAsset(quote.destinationChainId)) || bridgeRequestKey(quote) !== bridgeRequestKey(request) || quote.destinationChainId === quote.originChainId) {
     throw new Error("The quote no longer matches this wallet, amount, or route. Review a new quote.");
   }
   if (!isHash(quote.requestId) || !isWei(quote.amount, true) || !isWei(quote.amountOut, true) || !isWei(quote.minimumAmountOut, true) || BigInt(quote.minimumAmountOut) > BigInt(quote.amountOut)) {
@@ -402,7 +414,7 @@ export function parseStoredTransfer(raw: string, address: Address): TrackedBridg
   const assetsValid = isBridgeChainId(entry?.originChainId) && isBridgeChainId(entry?.destinationChainId) && isBridgeAssetSupported(entry.originChainId, entry.originAsset) && isBridgeAssetSupported(entry.destinationChainId, entry.destinationAsset);
   const legacyAssets = entry?.originAsset === undefined && entry?.destinationAsset === undefined;
   const validVersion = (entry?.version === 1 && legacyAssets && entry.depositKind === undefined) || (entry?.version === 2 && legacyAssets && erc20 && entry.originChainId === 5042 && typeof entry.depositData === "string") || (entry?.version === 3 && assetsValid && typeof entry.depositData === "string" && (entry.depositKind === undefined || erc20) && erc20 === !/^0x0{40}$/.test(bridgeCurrency(entry.originChainId, entry.originAsset, "input").address));
-  if (!validVersion || typeof entry.address !== "string" || entry.address.toLowerCase() !== address.toLowerCase() || !isAddress(entry.address) || !isBridgeChainId(entry.originChainId) || !isBridgeChainId(entry.destinationChainId) || entry.destinationChainId === entry.originChainId || !isHash(entry.requestId) || !isWei(entry.amount, true) || !Number.isFinite(entry.createdAt) || entry.createdAt <= 0 || (entry.sourceHash !== undefined && !isHash(entry.sourceHash)) || !Array.isArray(entry.destinationHashes) || entry.destinationHashes.length > 50 || !entry.destinationHashes.every(isHash) || (entry.status !== "uncertain" && !STATUSES.includes(entry.status)) || (entry.depositData !== undefined && !new RegExp(`^0x[0-9a-fA-F]{${erc20 ? 264 : 136}}$`).test(entry.depositData)) || (entry.failureReason !== undefined && entry.failureReason !== "source-reverted")) {
+  if (!validVersion || typeof entry.address !== "string" || entry.address.toLowerCase() !== address.toLowerCase() || !isAddress(entry.address) || !isBridgeChainId(entry.originChainId) || !isBridgeDestination(entry.destinationChainId) || entry.destinationChainId === entry.originChainId || !isHash(entry.requestId) || !isWei(entry.amount, true) || !Number.isFinite(entry.createdAt) || entry.createdAt <= 0 || (entry.sourceHash !== undefined && !isHash(entry.sourceHash)) || !Array.isArray(entry.destinationHashes) || entry.destinationHashes.length > 50 || !entry.destinationHashes.every(isHash) || (entry.status !== "uncertain" && !STATUSES.includes(entry.status)) || (entry.depositData !== undefined && !new RegExp(`^0x[0-9a-fA-F]{${erc20 ? 264 : 136}}$`).test(entry.depositData)) || (entry.failureReason !== undefined && entry.failureReason !== "source-reverted")) {
     throw new Error("Saved bridge recovery data could not be read. Check your transfer on Relay before trying again.");
   }
   if (erc20) {
diff --git a/app/src/lib/bridge/relay.fixture.ts b/app/src/lib/bridge/relay.fixture.ts
index 9e0a4f03..20c73c44 100644
--- a/app/src/lib/bridge/relay.fixture.ts
+++ b/app/src/lib/bridge/relay.fixture.ts
@@ -1,6 +1,6 @@
 import { encodeFunctionData, zeroAddress } from "viem";
 import { getOrderId, type Order } from "./relay-order";
-import { BRIDGE_CHAINS, BRIDGE_INPUT_CURRENCIES, bridgeCurrency, isDollarAsset, type BridgeAsset, type BridgeChainId, type BridgeQuoteRequest } from "./types";
+import { BRIDGE_CHAINS, BRIDGE_CHAIN_IDS, BRIDGE_INPUT_CURRENCIES, bridgeCurrency, isDollarAsset, type BridgeAsset, type BridgeChainId, type BridgeQuoteRequest } from "./types";
 import { APPROVAL_ABI, DEPOSIT_ABI, ERC20_DEPOSIT_ABI, RELAY_DEPOSITORY } from "./validation";
 
 // Compact, read-only mainnet quote captured with Relay's public example account.
@@ -14,10 +14,10 @@ const extraData = `0x${router.slice(2).padStart(64, "0")}`;
 export const FIXTURE_INPUT: BridgeQuoteRequest = { address: FIXTURE_ADDRESS, originChainId: 8453, destinationChainId: 4663, amount: "10000000000000000" };
 
 export function relayChainsFixture() {
-  return { chains: ([8453, 4663, 5042] as BridgeChainId[]).map((id) => ({
+  return { chains: BRIDGE_CHAIN_IDS.map((id) => ({
     id, vmType: "evm", disabled: false, depositEnabled: true, blockProductionLagging: false,
     protocol: { v2: { chainId: BRIDGE_CHAINS[id].key, depository: RELAY_DEPOSITORY } },
-    currency: { address: zeroAddress, symbol: id === 5042 ? "USDC" : "ETH", decimals: 18, supportsBridging: true },
+    currency: { address: zeroAddress, symbol: BRIDGE_CHAINS[id].symbol, decimals: 18, supportsBridging: true },
     contracts: { erc20Router: router }, solverAddresses: ["0xf70da97812cb96acdf810712aa562db8dfa3dbef"],
   })) };
 }
@@ -103,7 +103,7 @@ export function relayRouteFixture(originChainId: BridgeChainId, destinationChain
   quote.fees.gas.currency.symbol = BRIDGE_CHAINS[originChainId].symbol;
   quote.fees.relayer.amount = feeAmount;
   quote.fees.gas.amount = originChainId === 5042 ? "3000000000000000" : "671181819574";
-  const orderId = getOrderId(order as Order, { base: "ethereum-vm", robinhood: "ethereum-vm", arc: "ethereum-vm" });
+  const orderId = getOrderId(order as Order, Object.fromEntries(BRIDGE_CHAIN_IDS.map((id) => [BRIDGE_CHAINS[id].key, "ethereum-vm" as const])));
   quote.protocol.v2.orderId = orderId;
   quote.steps[0].items[0].data.data = erc20
     ? encodeFunctionData({ abi: ERC20_DEPOSIT_ABI, functionName: "depositErc20", args: [input.address, inputCurrency.address, BigInt(amount), orderId] })
diff --git a/app/src/lib/bridge/relay.live.test.ts b/app/src/lib/bridge/relay.live.test.ts
index 292f3c8a..54f16ef9 100644
--- a/app/src/lib/bridge/relay.live.test.ts
+++ b/app/src/lib/bridge/relay.live.test.ts
@@ -2,12 +2,12 @@ import assert from "node:assert/strict";
 import { test } from "node:test";
 import { getBridgeQuote, getBridgeStatus } from "./relay.ts";
 import { formatUnits } from "viem";
-import { BRIDGE_ASSETS, BRIDGE_CHAINS, bridgeCurrency, type BridgeChainId } from "./types.ts";
+import { BRIDGE_ASSETS, BRIDGE_CHAINS, BRIDGE_CHAIN_IDS, BRIDGE_DESTINATION_IDS, bridgeCurrency } from "./types.ts";
 
 // Explicit opt-in. This only requests quotes/status using a public dummy address;
 // it never connects a wallet, signs, or submits a transaction.
-const chains = [8453, 4663, 5042] as BridgeChainId[];
-for (const originChainId of chains) for (const destinationChainId of chains) {
+// Every source (the launch chains and the funding networks) into every launch chain: forty-six routes.
+for (const originChainId of BRIDGE_CHAIN_IDS) for (const destinationChainId of BRIDGE_DESTINATION_IDS) {
   if (originChainId === destinationChainId) continue;
   for (const originAsset of BRIDGE_ASSETS[originChainId]) for (const destinationAsset of BRIDGE_ASSETS[destinationChainId]) {
   test(`read-only live Relay ${originChainId}:${originAsset}→${destinationChainId}:${destinationAsset}`, { skip: process.env.RUN_BRIDGE_LIVE_TESTS !== "1" }, async (t) => {
diff --git a/app/src/lib/bridge/relay.test.ts b/app/src/lib/bridge/relay.test.ts
index 097b5c71..a9ca368c 100644
--- a/app/src/lib/bridge/relay.test.ts
+++ b/app/src/lib/bridge/relay.test.ts
@@ -3,7 +3,7 @@ import { test } from "node:test";
 import { encodeFunctionData, parseAbi, zeroAddress } from "viem";
 import { APPROVAL_ABI, BridgeApiError, ERC20_DEPOSIT_ABI, RELAY_DEPOSITORY, parseBridgeRequest, validateRelayChains, validateRelayQuote } from "./validation.ts";
 import { getOrderId, type Order } from "./relay-order.ts";
-import { ARC_USDC, BASE_USDC, BRIDGE_INPUT_CURRENCIES, ROBINHOOD_USDG, bridgeCurrency, type BridgeAsset, type BridgeChainId } from "./types.ts";
+import { ARBITRUM_USDC, ARC_USDC, BASE_USDC, BRIDGE_ASSETS, BRIDGE_DESTINATION_IDS, BRIDGE_FUNDING_IDS, BRIDGE_INPUT_CURRENCIES, ETHEREUM_USDC, OPTIMISM_USDC, ROBINHOOD_USDG, bridgeCurrency, type BridgeAsset, type BridgeChainId } from "./types.ts";
 import { BRIDGE_PRIVATE_HEADERS, bridgeErrorResponse, getBridgeQuote, getBridgeStatus, readBridgeJson } from "./relay.ts";
 import { ARC_FIXTURE_NOW, ARC_FIXTURE_ORDER_ID, ARC_OUTBOUND_FIXTURE_NOW, ARC_OUTBOUND_ORDER_ID, BASE_USDC_FIXTURE_NOW, BASE_USDC_ORDER_ID, FIXTURE_INPUT, FIXTURE_NOW, FIXTURE_REQUEST_ID, addApprovalFixture, relayArcOutboundFixture, relayArcQuoteFixture, relayBaseUsdcFixture, relayChainsFixture, relayQuoteFixture, relayRouteFixture } from "./relay.fixture.ts";
 import { parseBridgeQuoteRejection } from "./client.ts";
@@ -472,6 +472,62 @@ test("USDG cannot be swapped for another token, another chain's dollar or other
   assert.doesNotThrow(rebound(4663, 8453, "USDG", "USDC", () => {}));
 });
 
+test("funding networks verify into every launch chain, approving exactly their own native USDC", () => {
+  const usdc = { 1: ETHEREUM_USDC, 42161: ARBITRUM_USDC, 10: OPTIMISM_USDC } as const;
+  let routes = 0;
+  for (const origin of BRIDGE_FUNDING_IDS) for (const destination of BRIDGE_DESTINATION_IDS) {
+    for (const originAsset of BRIDGE_ASSETS[origin]) for (const destinationAsset of BRIDGE_ASSETS[destination]) {
+      const route = `${origin}:${originAsset}→${destination}:${destinationAsset}`;
+      const { input, quote } = relayRouteFixture(origin, destination, originAsset, destinationAsset);
+      const metadata = validateRelayChains(relayChainsFixture(), input);
+      // the solver hub (Base) is always checked alongside the two ends
+      assert.deepEqual(Object.keys(metadata.vmTypes).sort(), [...new Set(["base", quote.protocol.v2.orderData.inputs[0].payment.chainId, quote.protocol.v2.orderData.output.chainId])].sort(), route);
+      const validated = validateRelayQuote(quote, input, metadata, FIXTURE_NOW);
+      assert.equal(validated.transaction.to, RELAY_DEPOSITORY, route);
+      assert.equal(validated.transaction.chainId, origin, route);
+      if (originAsset === "USDC") assert.deepEqual(validated.approval, { token: usdc[origin], spender: RELAY_DEPOSITORY, amount: input.amount }, route);
+      else assert.equal(validated.approval, undefined, route);
+      routes++;
+    }
+  }
+  assert.equal(routes, 30);
+});
+
+test("a funding network is never a destination, and its USDC cannot be swapped for another network's", () => {
+  for (const destinationChainId of BRIDGE_FUNDING_IDS) {
+    for (const originChainId of [8453, 4663, 5042, ...BRIDGE_FUNDING_IDS.filter((id) => id !== destinationChainId)] as BridgeChainId[]) {
+      assert.throws(() => parseBridgeRequest({ address: FIXTURE_INPUT.address, originChainId, destinationChainId, amount: "1000000" }), (error: unknown) => error instanceof BridgeApiError && error.status === 400);
+    }
+  }
+  assert.equal(parseBridgeRequest({ address: FIXTURE_INPUT.address, originChainId: 42161, destinationChainId: 4663, originAsset: "USDC", destinationAsset: "USDG", amount: "1000000" }).originChainId, 42161);
+  const rebound = (token: string) => {
+    const { input, quote } = relayRouteFixture(1, 8453, "USDC", "USDC");
+    quote.protocol.v2.orderData.inputs[0].payment.currency = token;
+    quote.protocol.v2.orderData.inputs[0].refunds[0].currency = token;
+    const metadata = validateRelayChains(relayChainsFixture(), input);
+    const orderId = getOrderId(quote.protocol.v2.orderData as Order, metadata.vmTypes);
+    quote.protocol.v2.orderId = orderId;
+    quote.steps[0].items[0].data.data = encodeFunctionData({ abi: ERC20_DEPOSIT_ABI, functionName: "depositErc20", args: [input.address, token as `0x${string}`, BigInt(input.amount), orderId] });
+    return () => validateRelayQuote(quote, input, metadata, FIXTURE_NOW);
+  };
+  for (const token of [ARBITRUM_USDC, OPTIMISM_USDC, BASE_USDC, zeroAddress]) assert.throws(rebound(token), BridgeApiError, token);
+  assert.doesNotThrow(rebound(ETHEREUM_USDC));
+});
+
+test("a funding network missing from Relay's catalogue, or not yet on the pinned router, fails closed", () => {
+  const input = { address: FIXTURE_INPUT.address, originChainId: 42161, destinationChainId: 8453, amount: "1000000" } as const;
+  const missing = relayChainsFixture();
+  missing.chains = missing.chains.filter((chain) => chain.id !== 42161);
+  assert.throws(() => validateRelayChains(missing, input), BridgeApiError);
+  const moved = relayChainsFixture();
+  moved.chains.find((chain) => chain.id === 42161)!.contracts.erc20Router = "0x000000000000000000000000000000000000dead";
+  assert.throws(() => validateRelayChains(moved, input), BridgeApiError);
+  const renamed = relayChainsFixture();
+  renamed.chains.find((chain) => chain.id === 42161)!.protocol.v2.chainId = "arbitrum-nova";
+  assert.throws(() => validateRelayChains(renamed, input), BridgeApiError);
+  assert.doesNotThrow(() => validateRelayChains(relayChainsFixture(), input));
+});
+
 test("a dollar is counted against a dollar: USDC and USDG routes never guarantee under 95% or claim over 105%", () => {
   // the provider's own impact estimate stays a mild -0.12% throughout, so only the unit comparison can refuse these
   const delivering = (origin: BridgeChainId, destination: BridgeChainId, originAsset: BridgeAsset, destinationAsset: BridgeAsset, percent: bigint) => {
diff --git a/app/src/lib/bridge/rpc.ts b/app/src/lib/bridge/rpc.ts
new file mode 100644
index 00000000..5d1c97e2
--- /dev/null
+++ b/app/src/lib/bridge/rpc.ts
@@ -0,0 +1,20 @@
+import "server-only";
+import { BRIDGE_CHAINS, BRIDGE_FUNDING_IDS } from "./types";
+
+/**
+ * Upstreams for the bridge's funding networks behind the same-origin RPC proxy (api/rpc). A keyed URL from the
+ * environment wins (Alchemy serves all three with the key the launch chains use); unset, a public node answers.
+ * The proxy's read-only method allowlist and per-IP budget apply to these exactly as to the launch chains.
+ */
+const FUNDING_RPC = {
+  1: { env: "ETHEREUM_RPC_URL", fallback: "https://ethereum-rpc.publicnode.com" },
+  42161: { env: "ARBITRUM_RPC_URL", fallback: "https://arb1.arbitrum.io/rpc" },
+  10: { env: "OPTIMISM_RPC_URL", fallback: "https://mainnet.optimism.io" },
+} as const satisfies Record<(typeof BRIDGE_FUNDING_IDS)[number], { env: string; fallback: string }>;
+
+/** The upstream for a proxy `?chain=` key naming a funding network (ethereum, arbitrum, optimism), else null. */
+export function bridgeFundingUpstream(key: string): string | null {
+  const id = BRIDGE_FUNDING_IDS.find((candidate) => BRIDGE_CHAINS[candidate].key === key);
+  if (id === undefined) return null;
+  return process.env[FUNDING_RPC[id].env]?.trim() || FUNDING_RPC[id].fallback;
+}
diff --git a/app/src/lib/bridge/transaction-preflight.test.ts b/app/src/lib/bridge/transaction-preflight.test.ts
index 351dd90e..b06cfe8a 100644
--- a/app/src/lib/bridge/transaction-preflight.test.ts
+++ b/app/src/lib/bridge/transaction-preflight.test.ts
@@ -4,7 +4,7 @@ import { encodeFunctionData, type Address, type Hex } from "viem";
 import { submitExactApproval, type ApprovalDependencies, type ApprovalRequest } from "./approval";
 import { ERC20_DEPOSIT_ABI, NATIVE_DEPOSIT_ABI, RELAY_DEPOSITORY, submitBridgeDeposit, type DepositDependencies } from "./client";
 import { assertBridgeWalletQueueClear } from "./transaction-preflight";
-import { BRIDGE_ASSETS, BRIDGE_CHAINS, BRIDGE_CHAIN_IDS, bridgeCurrency, type BridgeAsset, type BridgeChainId, type BridgeQuote } from "./types";
+import { BRIDGE_ASSETS, BRIDGE_CHAINS, BRIDGE_CHAIN_IDS, BRIDGE_DESTINATION_IDS, bridgeCurrency, type BridgeAsset, type BridgeChainId, type BridgeQuote } from "./types";
 
 const ADDRESS = "0x1111111111111111111111111111111111111111" as Address;
 const HASH = `0x${"a".repeat(64)}` as Hex;
@@ -159,9 +159,10 @@ function depositScenario(q: BridgeQuote, pending: number, latest: number) {
   return { deps, events };
 }
 
-test("all sixteen supported deposit routes block queued nonces before journaling or sending", async () => {
+test("all forty-six supported deposit routes block queued nonces before journaling or sending", async () => {
   let routes = 0;
-  for (const origin of BRIDGE_CHAIN_IDS) for (const destination of BRIDGE_CHAIN_IDS) {
+  // sixteen between the launch chains, thirty from the funding networks (two assets each to five launch-chain assets)
+  for (const origin of BRIDGE_CHAIN_IDS) for (const destination of BRIDGE_DESTINATION_IDS) {
     if (origin === destination) continue;
     for (const originAsset of BRIDGE_ASSETS[origin]) for (const destinationAsset of BRIDGE_ASSETS[destination]) {
       const q = quote(origin, destination, originAsset, destinationAsset);
@@ -171,7 +172,7 @@ test("all sixteen supported deposit routes block queued nonces before journaling
       routes++;
     }
   }
-  assert.equal(routes, 16);
+  assert.equal(routes, 46);
 });
 
 test("clear queues preserve explicit approval and deposit submission order", async () => {
diff --git a/app/src/lib/bridge/types.test.ts b/app/src/lib/bridge/types.test.ts
index 199e7a0e..1b0ed214 100644
--- a/app/src/lib/bridge/types.test.ts
+++ b/app/src/lib/bridge/types.test.ts
@@ -39,7 +39,7 @@ test("Robinhood USDG is the launch form's own six-decimal contract in both direc
 });
 
 test("every chain keeps its gas token as the default and has at most one ERC-20", () => {
-  assert.deepEqual(BRIDGE_CHAIN_IDS.map(bridgeTokenAsset), ["USDC", "USDG", "USDC"]);
+  assert.deepEqual(BRIDGE_CHAIN_IDS.map(bridgeTokenAsset), ["USDC", "USDG", "USDC", "USDC", "USDC", "USDC"]);
   for (const chain of BRIDGE_CHAIN_IDS) {
     assert.equal(defaultBridgeAsset(chain), BRIDGE_CHAINS[chain].symbol);
     assert.ok(isBridgeAssetSupported(chain, defaultBridgeAsset(chain)), String(chain));
diff --git a/app/src/lib/bridge/types.ts b/app/src/lib/bridge/types.ts
index 68c9e6e1..7fa3f9ca 100644
--- a/app/src/lib/bridge/types.ts
+++ b/app/src/lib/bridge/types.ts
@@ -1,13 +1,26 @@
 import type { Address, Hex } from "viem";
 
-/** Bridge networks do not extend the launch registry. */
-export type BridgeChainId = 8453 | 4663 | 5042;
+/**
+ * Bridge networks do not extend the launch registry. Base, Robinhood Chain and Arc are where tokens launch, so funds
+ * move between them both ways. Ethereum, Arbitrum and Optimism are funding sources only: money arrives from them and
+ * never leaves to them. `key` is Relay's protocol.v2 name for the chain, checked against GET /chains on every quote.
+ */
+export type BridgeChainId = 8453 | 4663 | 5042 | 1 | 42161 | 10;
 export const BRIDGE_CHAINS = {
   8453: { name: "Base", key: "base", explorer: "https://basescan.org", symbol: "ETH", decimals: 18 },
   4663: { name: "Robinhood", key: "robinhood", explorer: "https://robinhoodchain.blockscout.com", symbol: "ETH", decimals: 18 },
   5042: { name: "Arc", key: "arc", explorer: "https://explorer.arc.io", symbol: "USDC", decimals: 18 },
+  1: { name: "Ethereum", key: "ethereum", explorer: "https://etherscan.io", symbol: "ETH", decimals: 18 },
+  42161: { name: "Arbitrum", key: "arbitrum", explorer: "https://arbiscan.io", symbol: "ETH", decimals: 18 },
+  10: { name: "Optimism", key: "optimism", explorer: "https://optimistic.etherscan.io", symbol: "ETH", decimals: 18 },
 } as const;
-export const BRIDGE_CHAIN_IDS = [8453, 4663, 5042] as const;
+/** Networks a transfer can arrive on: the launch chains. */
+export const BRIDGE_DESTINATION_IDS = [8453, 4663, 5042] as const;
+/** Networks that only fund the launch chains. */
+export const BRIDGE_FUNDING_IDS = [1, 42161, 10] as const;
+/** Every network a transfer can leave from, in picker order. */
+export const BRIDGE_CHAIN_IDS = [...BRIDGE_DESTINATION_IDS, ...BRIDGE_FUNDING_IDS] as const;
+export type BridgeDestinationId = (typeof BRIDGE_DESTINATION_IDS)[number];
 // Arc's ERC-20 USDC interface shares the native balance, but has its own
 // transfer semantics and SIX decimals. Never alias it to native zero-address USDC.
 export const ARC_USDC = "0x3600000000000000000000000000000000000000" as const;
@@ -16,6 +29,11 @@ export const BASE_USDC = "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913" as const;
 // form's default quote there (lib/launchpad/config.ts names the same contract). Robinhood USDC is still not offered.
 // https://docs.paxos.com/guides/stablecoin/usdg/mainnet
 export const ROBINHOOD_USDG = "0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168" as const;
+// Circle's native USDC on the funding networks (symbol USDC, name "USD Coin", six decimals, checked on-chain).
+// Never the bridged USDC.e that Arbitrum and Optimism also carry.
+export const ETHEREUM_USDC = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48" as const;
+export const ARBITRUM_USDC = "0xaf88d065e77c8cC2239327C5EDb3A432268e5831" as const;
+export const OPTIMISM_USDC = "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85" as const;
 export type BridgeAsset = "ETH" | "USDC" | "USDG";
 export type BridgeCurrency = { address: Address; symbol: BridgeAsset; decimals: 6 | 18 };
 const NATIVE_ADDRESS = "0x0000000000000000000000000000000000000000" as const;
@@ -33,12 +51,12 @@ const CURRENCIES: Record<BridgeChainId, Partial<Record<BridgeAsset, { input: Bri
   8453: { ETH: bothWays(native("ETH")), USDC: bothWays(token(BASE_USDC, "USDC")) },
   4663: { ETH: bothWays(native("ETH")), USDG: bothWays(token(ROBINHOOD_USDG, "USDG")) },
   5042: { USDC: { input: token(ARC_USDC, "USDC"), output: native("USDC") } },
+  // funding networks: only the input side is ever used, since nothing is sent to them
+  1: { ETH: bothWays(native("ETH")), USDC: bothWays(token(ETHEREUM_USDC, "USDC")) },
+  42161: { ETH: bothWays(native("ETH")), USDC: bothWays(token(ARBITRUM_USDC, "USDC")) },
+  10: { ETH: bothWays(native("ETH")), USDC: bothWays(token(OPTIMISM_USDC, "USDC")) },
 };
-export const BRIDGE_ASSETS: Record<BridgeChainId, readonly BridgeAsset[]> = {
-  8453: Object.keys(CURRENCIES[8453]) as BridgeAsset[],
-  4663: Object.keys(CURRENCIES[4663]) as BridgeAsset[],
-  5042: Object.keys(CURRENCIES[5042]) as BridgeAsset[],
-};
+export const BRIDGE_ASSETS = Object.fromEntries(BRIDGE_CHAIN_IDS.map((id) => [id, Object.keys(CURRENCIES[id]) as BridgeAsset[]])) as unknown as Record<BridgeChainId, readonly BridgeAsset[]>;
 /** What each asset is called in full, for pickers and screen readers. */
 export const BRIDGE_ASSET_NAMES: Record<BridgeAsset, string> = { ETH: "Ether", USDC: "USD Coin", USDG: "Global Dollar" };
 export function defaultBridgeAsset(chainId: BridgeChainId): BridgeAsset {
@@ -124,6 +142,16 @@ export type BridgeStatusResponse = {
 };
 
 export function isBridgeChainId(value: unknown): value is BridgeChainId {
-  return value === 8453 || value === 4663 || value === 5042;
+  return (BRIDGE_CHAIN_IDS as readonly unknown[]).includes(value);
+}
+
+/** Whether a transfer may arrive on this network. Funding networks never receive. */
+export function isBridgeDestination(value: unknown): value is BridgeDestinationId {
+  return (BRIDGE_DESTINATION_IDS as readonly unknown[]).includes(value);
+}
+
+/** Whether this network only funds the launch chains. */
+export function isBridgeFundingChain(value: unknown): value is (typeof BRIDGE_FUNDING_IDS)[number] {
+  return (BRIDGE_FUNDING_IDS as readonly unknown[]).includes(value);
 }
 
diff --git a/app/src/lib/bridge/validation.test.ts b/app/src/lib/bridge/validation.test.ts
index b26512d2..4d839a8d 100644
--- a/app/src/lib/bridge/validation.test.ts
+++ b/app/src/lib/bridge/validation.test.ts
@@ -147,5 +147,8 @@ test("status distinguishes refunds and delays and accepts waiting before hashes
   assert.equal(parseRelayStatus({ status: "delayed" }).status, "delayed");
   assert.equal(parseRelayStatus({ status: "refund", txHashes: [FIXTURE_REQUEST_ID] }).status, "refund");
   assert.throws(() => parseRelayStatus({ status: "success", txHashes: ["javascript:alert(1)"] }), BridgeApiError);
-  assert.throws(() => parseRelayStatus({ status: "success", destinationChainId: 1 }), BridgeApiError);
+  // a funding network can be a status's origin, never its destination; an unknown chain is neither
+  assert.equal(parseRelayStatus({ status: "success", originChainId: 42161, destinationChainId: 8453 }).status, "success");
+  for (const destinationChainId of [1, 42161, 10, 137]) assert.throws(() => parseRelayStatus({ status: "success", destinationChainId }), BridgeApiError);
+  assert.throws(() => parseRelayStatus({ status: "success", originChainId: 137 }), BridgeApiError);
 });
diff --git a/app/src/lib/bridge/validation.ts b/app/src/lib/bridge/validation.ts
index 67e541d6..bf155b3d 100644
--- a/app/src/lib/bridge/validation.ts
+++ b/app/src/lib/bridge/validation.ts
@@ -1,12 +1,12 @@
 import "server-only";
 import { getOrderId, type Order } from "./relay-order";
 import { encodeFunctionData, formatEther, formatUnits, isAddress, parseAbi, zeroAddress, type Hex } from "viem";
-import { BRIDGE_CHAINS, bridgeCurrency, bridgeFeePercent, isBridgeAssetSupported, isBridgeChainId, isDollarAsset, type BridgeCurrency, type BridgeChainId, type BridgeQuote, type BridgeQuoteRejection, type BridgeQuoteRequest, type BridgeStatus, type BridgeStatusResponse } from "./types";
+import { BRIDGE_CHAINS, bridgeCurrency, bridgeFeePercent, isBridgeAssetSupported, isBridgeChainId, isBridgeDestination, isDollarAsset, type BridgeCurrency, type BridgeChainId, type BridgeQuote, type BridgeQuoteRejection, type BridgeQuoteRequest, type BridgeStatus, type BridgeStatusResponse } from "./types";
 
 // Independently pinned, then checked against GET /chains. Never trust a quote to
 // supply the address against which that same quote is validated.
 export const RELAY_DEPOSITORY = "0x4cd00e387622c35bddb9b4c962c136462338bc31";
-// Relay's execution routers on Base, Robinhood Chain and Arc (the "Cancun" column of its contract-versions table,
+// Relay's execution routers on every bridge network (the "Cancun" column of its contract-versions table,
 // docs.relay.link/references/api/api_resources/contract-addresses): v3.2 first, then v3. Relay made v3.2 the default on
 // 2026-10-26 and keeps both live through the transition, telling integrators who pin addresses to allow both. A router
 // Relay publishes later is rejected until it is added here: every quote then fails closed, which the opt-in live tests
@@ -58,7 +58,8 @@ export function parseBridgeRequest(value: unknown): BridgeQuoteRequest {
     const required = ["address", "originChainId", "destinationChainId", "amount"];
     ensure(required.every((key) => Object.hasOwn(b, key)) && Object.keys(b).every((key) => [...required, "originAsset", "destinationAsset"].includes(key)));
     ensure(typeof b.address === "string" && isAddress(b.address, { strict: false }) && !sameAddress(b.address, zeroAddress));
-    ensure(isBridgeChainId(b.originChainId) && isBridgeChainId(b.destinationChainId) && b.originChainId !== b.destinationChainId);
+    // funding networks (Ethereum, Arbitrum, Optimism) send but never receive
+    ensure(isBridgeChainId(b.originChainId) && isBridgeDestination(b.destinationChainId) && b.originChainId !== b.destinationChainId);
     ensure(b.originAsset === undefined || isBridgeAssetSupported(b.originChainId, b.originAsset));
     ensure(b.destinationAsset === undefined || isBridgeAssetSupported(b.destinationChainId, b.destinationAsset));
     const amount = uint(b.amount, true);
@@ -230,9 +231,8 @@ export function parseRelayStatus(value: unknown): BridgeStatusResponse {
   const response = object(value);
   const statuses: BridgeStatus[] = ["waiting", "depositing", "pending", "submitted", "delayed", "success", "refund", "failure"];
   ensure(statuses.includes(response.status as BridgeStatus));
-  for (const key of ["originChainId", "destinationChainId"]) {
-    if (response[key] !== undefined) ensure(isBridgeChainId(response[key]));
-  }
+  if (response.originChainId !== undefined) ensure(isBridgeChainId(response.originChainId));
+  if (response.destinationChainId !== undefined) ensure(isBridgeDestination(response.destinationChainId));
   const hashes = (value: unknown): Hex[] => {
     if (value === undefined) return [];
     const values = list(value);
diff --git a/app/src/lib/wagmi.ts b/app/src/lib/wagmi.ts
index 009c649c..879f439a 100644
--- a/app/src/lib/wagmi.ts
+++ b/app/src/lib/wagmi.ts
@@ -3,15 +3,21 @@ import { injected, coinbaseWallet } from "wagmi/connectors";
 import type { Chain } from "viem";
 import { CHAINS, CHAIN_KEYS, DEFAULT_CHAIN } from "./chainPublic";
 import { browserRpc } from "./launchpad/config";
+import { BRIDGE_FUNDING_WALLET_CHAINS, bridgeFundingRpc } from "./bridge/chains";
+import { BRIDGE_FUNDING_IDS } from "./bridge/types";
 
-// Every chain in one config, the default first. Reads/simulations go through our RPC proxy per chain
-// (or a dev override); wallets send transactions through their own provider.
+// Every chain in one config, the default first, then the bridge's funding networks (Ethereum, Arbitrum, Optimism),
+// which nothing launches on. Reads/simulations go through our RPC proxy per chain (or a dev override); wallets send
+// transactions through their own provider.
 const keys = [DEFAULT_CHAIN, ...CHAIN_KEYS.filter((k) => k !== DEFAULT_CHAIN)];
-const chains = keys.map((k) => CHAINS[k]) as [Chain, ...Chain[]];
+const chains = [...keys.map((k) => CHAINS[k]), ...BRIDGE_FUNDING_WALLET_CHAINS] as [Chain, ...Chain[]];
 
 export const wagmiConfig = createConfig({
   chains,
   connectors: [injected(), coinbaseWallet({ appName: "openlaunch.lol", preference: { options: "all", telemetry: false } })],
-  transports: Object.fromEntries(keys.map((k) => [CHAINS[k].id, http(browserRpc(k), { batch: true })])),
+  transports: Object.fromEntries([
+    ...keys.map((k) => [CHAINS[k].id, http(browserRpc(k), { batch: true })]),
+    ...BRIDGE_FUNDING_IDS.map((id) => [id, http(bridgeFundingRpc(id), { batch: true })]),
+  ]),
   ssr: true,
 });
diff --git a/docs/bridge.md b/docs/bridge.md
index 63c9e947..3d9d9bd0 100644
--- a/docs/bridge.md
+++ b/docs/bridge.md
@@ -1,13 +1,13 @@
-# Base, Robinhood and Arc bridge
+# Base, Robinhood and Arc bridge (funded from Ethereum, Arbitrum and Optimism)
 
-The header's **Bridge** action opens a focused funding panel without leaving the current token or launch page. It supports Base (8453), Robinhood Chain (4663), and Arc mainnet (5042), to the same connected wallet address. Base sends/receives ETH or official USDC; Robinhood sends/receives ETH or USDG (Global Dollar, the chain's main stablecoin and the launch form's default quote there). Arc receives native USDC and sends USDC through its ERC-20 interface. Relay converts between ETH, USDC and USDG at the reviewed quote. This does not add launched tokens or GITLAWB, change the launch-chain registry, or deploy contracts.
+The header's **Bridge** action opens a focused funding panel without leaving the current token or launch page. It moves funds between Base (8453), Robinhood Chain (4663), and Arc mainnet (5042), and into them from Ethereum (1), Arbitrum (42161) and Optimism (10), always to the same connected wallet address. The three funding networks send only: nothing is ever bridged to them. Base sends/receives ETH or official USDC; Robinhood sends/receives ETH or USDG (Global Dollar, the chain's main stablecoin and the launch form's default quote there). Arc receives native USDC and sends USDC through its ERC-20 interface. Ethereum, Arbitrum and Optimism send ETH or Circle's native USDC. Relay converts between ETH, USDC and USDG at the reviewed quote. This does not add launched tokens or GITLAWB, change the launch-chain registry, or deploy contracts.
 
 ## Integration
 
 - Relay supplies quotes and transfer status. Openlaunch charges no application fee; Relay and source-network gas still cost money.
 - `POST /api/bridge/quote` accepts `{ address, originChainId, destinationChainId, originAsset, destinationAsset, amount }`. Asset choices are allowlisted `ETH`, `USDC` or `USDG` for that chain, never arbitrary addresses. Omitted asset fields retain legacy defaults: Base/Robinhood ETH, Arc USDC. The integer amount uses 18 decimals for ETH inputs and **6 decimals for USDC and USDG inputs**. Outputs use 6 decimals for Base USDC and Robinhood USDG, 18 for ETH or Arc native USDC. `GET /api/bridge/status?requestId=…` returns normalized provider state and transaction hashes.
 - Base USDC is Circle's `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`. Its ERC-20 balance and allowance are checked separately from native ETH gas. An approval and deposit both require an ETH reserve; a USDC balance cannot pay Base gas. The picker, fee labels, quote identity and recovery journal all retain the selected asset.
-- Requests use a fixed upstream, timeout and streamed body-size bounds, existing per-IP limits, and private/no-store caching. The API does not need a wallet signature. Relay quotes/status stay server-side. Arc balance, allowance, gas and receipt reads go through the same-origin `/api/rpc?chain=arc` proxy (upstream `ARC_RPC_URL`, else the official public node), so the CSP gains no third-party origin and script restrictions are unchanged. Public Base and Arc nodes rate-limit a single quote's burst of reads; the proxy turns rate-limit and malformed replies into HTTP 429/502 so viem retries them, and production should point `BASE_RPC_URL` and `ARC_RPC_URL` at keyed providers.
+- Requests use a fixed upstream, timeout and streamed body-size bounds, existing per-IP limits, and private/no-store caching. The API does not need a wallet signature. Relay quotes/status stay server-side. Arc balance, allowance, gas and receipt reads go through the same-origin `/api/rpc?chain=arc` proxy (upstream `ARC_RPC_URL`, else the official public node), so the CSP gains no third-party origin and script restrictions are unchanged. The funding networks read the same way through `/api/rpc?chain=ethereum|arbitrum|optimism` (upstreams `ETHEREUM_RPC_URL`, `ARBITRUM_RPC_URL`, `OPTIMISM_RPC_URL`, else publicnode for Ethereum and the official Arbitrum and Optimism nodes), with the same read-only allowlist and per-IP budget. Public Base and Arc nodes rate-limit a single quote's burst of reads; the proxy turns rate-limit and malformed replies into HTTP 429/502 so viem retries them, and production should point `BASE_RPC_URL` and `ARC_RPC_URL` at keyed providers.
 - Arc's native USDC (18 decimals) and ERC-20 interface `0x3600000000000000000000000000000000000000` (6 decimals) share one balance but are **not interchangeable transfer interfaces**. Input parsing, deposit verification and recovery distinguish them. Gas budgeting converts the USDC input into native units and leaves a reserve for network fees.
 - `RELAY_API_KEY` is optional, server-only, and forwarded as `x-api-key` if configured. Read-only smoke tests passed without a key. Higher production traffic may require a Relay key or adjusted provider limits. Do not expose the key through a `NEXT_PUBLIC_` variable.
 - The server reconstructs the order hash using a narrow EVM/v1-only extraction of the MIT-licensed `@relay-protocol/settlement-sdk` 0.0.143 schema, normalizer and hashing algorithm, with the existing Viem dependency. This avoids shipping the SDK's unrelated multi-chain dependency subtree and its known vulnerabilities. The exact npm tarball, gitHead, upstream source SHA-256 hashes, MIT notice and 256 official-SDK compatibility vectors are recorded in [the provenance notice](../app/src/lib/bridge/relay-order.NOTICE.md); unsupported protocol versions and non-EVM orders fail closed.
@@ -32,7 +32,7 @@ An interrupted wallet response is **uncertain**, not failed. The app must not si
 
 ## Limits and rollout
 
-- Three mainnet networks, same-wallet recipient only. ETH on Base/Robinhood, USDC on Base/Arc and USDG on Robinhood. No arbitrary tokens, recipients, unlimited allowances, deposits from exchanges, custom swap calls, or extra networks.
+- Three launch networks both ways and three funding networks one way, same-wallet recipient only. ETH on Base/Robinhood, USDC on Base/Arc, USDG on Robinhood, and ETH or native USDC from Ethereum/Arbitrum/Optimism. No arbitrary tokens, recipients, unlimited allowances, deposits from exchanges, custom swap calls, bridged USDC.e, or other networks.
 - Robinhood USDC remains unavailable. On 2026-09-16, the official canonical gateway mapped Ethereum USDC to bridged `0x80e0e24718dbFcad49ECAA6F1e6C89A190586cA8` (6 decimals); this is not Circle-native issuance. Read-only Relay probes at 25 USDC returned roughly 21% loss outbound, while inbound routes were rejected for roughly 92% swap impact. Outbound responses required an approval-proxy/swap flow, not our validated direct deposit. Do not enable this asset or loosen safeguards without fresh route validation and separately reviewed support. USDG is offered as its own named asset, never as a silent stand-in for USDC.
 - Relay is a third-party bridge protocol. Its availability, liquidity, estimates and settlement are not guaranteed by Openlaunch. Provider response changes fail closed until reviewed.
 - Funds never pass through an Openlaunch wallet or new Openlaunch contract.
@@ -55,6 +55,14 @@ These tests never connect a wallet or submit a transaction.
 
 `/ui-review-bridge` is a development-only visual fixture with disconnected, quote, quoting, high-fee, expired, error, pending, success, uncertain and refund states, plus approval/recovery states. Its synthetic data cannot execute a transaction, and the route returns 404 outside development. The real header action uses the actual integration.
 
+### Funding from Ethereum, Arbitrum and Optimism (2026-11-10)
+
+- The three networks are sources only. A request, quote, saved transfer or status naming one as the destination is refused (server and client), the reverse button is disabled while one is the source, and the destination picker lists the launch chains alone. Picking the destination as the source moves the destination to another launch chain instead of swapping a funding network into it.
+- Each sends ETH or Circle's native USDC, read on-chain as symbol `USDC`, name `USD Coin`, 6 decimals: Ethereum `0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48`, Arbitrum `0xaf88d065e77c8cC2239327C5EDb3A432268e5831`, Optimism `0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85`. Bridged USDC.e is not offered. A USDC source uses the same exact approval, fresh quote and `depositErc20` flow as Base USDC, with ETH kept for gas.
+- Relay's `GET /chains` lists all three with protocol.v2 names `ethereum`, `arbitrum` and `optimism`, the pinned depository and the v3.2 router, and their quotes return the same direct-deposit orders settled through the Base solver hub. No rule was loosened; the validator checks the funding network's catalogue entry exactly as it checks a launch chain's.
+- The wallet config adds the three chains so the wallet can switch to them; their reads go through the RPC proxy. A wallet already on one of them is offered a one-tap "Send from" shortcut in the panel. The wallet menu names the network and links its explorer, without the unsupported-network warning.
+- Thirty routes are new, forty-six in all (sixteen between the launch chains, thirty from the funding networks). All forty-six passed the read-only live tests. No wallet signed anything; a small real transfer from each funding network is still needed before this is described as exercised.
+
 ### USDG on Robinhood Chain (2026-11-10)
 
 - USDG is `0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168` on Robinhood Chain: read on-chain as symbol `USDG`, name `Global Dollar`, 6 decimals, and the same contract the launch form already prices in (`lib/launchpad/config.ts`; a test keeps the two equal). It is issued by Paxos ([USDG mainnet addresses](https://docs.paxos.com/guides/stablecoin/usdg/mainnet)) and is one of the two currencies Relay's solver holds on that chain.