diff --git a/CHANGELOG.md b/CHANGELOG.md
index 94f0bbf..a31bad0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # CHANGELOG
 
+## Next Release
+
+- Sends card details in the request body instead of the URL query string when `referral_customer.add_credit_card` creates a Stripe token
+
 ## v10.7.0 (2026-06-25)
 
 - Adds `params` to `request_pin` ensuring users can pass `easypost_details` to the call.
diff --git a/easypost/services/referral_customer_service.py b/easypost/services/referral_customer_service.py
index 17a3c53..1cbd8cf 100644
--- a/easypost/services/referral_customer_service.py
+++ b/easypost/services/referral_customer_service.py
@@ -222,9 +222,11 @@ def _create_stripe_token(
         form_encoded_params = Requestor.form_encode_params(credit_card_dict)
         url = "https://api.stripe.com/v1/tokens"
 
+        # Card details must travel in the form-encoded request body, never in the URL,
+        # so they cannot end up in access logs, proxy logs, or Referer headers.
         stripe_response = requests.post(
             url,
-            params=form_encoded_params,
+            data=form_encoded_params,
             headers=headers,
             auth=requests.auth.HTTPBasicAuth(easypost_stripe_key, ""),
             timeout=TIMEOUT,