VEDS

Project Assumptions

Microservices back-end for managing projects and their tasks, built on:

• Domain-Driven Design.
• Event-Driven Architecture.
• Hexagonal Architecture.
• Choreography and the Saga pattern for distributed transactions.
• Outbox and inbox patterns for reliable messaging.
• SOLID.

The front-end is FastDo.

Link: https://fastdo.vertyll.dev

Architecture Graph

Technology Stack

Back-end

• Spring Boot.
• Kotlin.
• Gradle Kotlin DSL (a separate build for each service, joined as a composite build).
• PostgreSQL (a separate database for each service).
• Apache Kafka (KRaft).
• Apache Avro with Schema Registry.
• Redis (API gateway sessions).
• Garage (S3-compatible storage for files).
• JUnit.
• Testcontainers.
• Spring Security.
• Spring Data JPA.
• Spring Cloud Gateway.
• OpenAPI (Swagger).

Authentication

• Identity provider: Keycloak (realm veds); the application never sees a password.
• Pattern: BFF; only the API gateway holds tokens, the browser holds only a session cookie.
• Session store: Redis (Spring Session), every attribute encrypted by the gateway.
• JWT: exchanged per service (RFC 8693), so a token leaked from one service opens no other.
• Authorization: permissions are granted to roles; each service decides from its own projection.
• Details: Keycloak and Authorization.

Core back-end

• The application has an exception handling mechanism (RFC 9457 problem details with message codes).
• The application has a logging mechanism.
• The application has separate environments for local and prod.
• The application has a dedicated configuration file.
• The application has RBAC with permissions per role, announced to every service through Kafka.
• The application has Flyway database migration mechanism.
• The application has optimistic locking with ETag and If-Match headers.
• The application has translations (ICU MessageFormat) owned by the service that declares them.
• And many other features that can be found in the application code.

Other

• Docker for development environment.
• Detekt for static code analysis.
• ktlint for code formatting.
• ArchUnit for executable architecture rules.
• Dokka for code documentation.
• OpenTofu for Kafka topic provisioning.

Documentation

• Contents – every document in the repository, the module it belongs to, and what it covers.
• Glossary – every term the docs use, and where it is explained.
• Standards – the RFCs and specifications the code implements or depends on.