Backend API Documentation

Architecture Overview

The backend follows Clean Architecture with these layers:

Presentation Layer (handlers/)
    ↓
Application Layer (usecases/)
    ↓
Domain Layer (domain/)
    ↓
Infrastructure Layer (adapters/, infrastructure/)

API Endpoints

Endpoint	Method	Purpose	Handler Function
/	GET	Home page	HandleHome()
/faq	GET	FAQ page	HandleFAQ()
/healthz	GET	Health check	HandleHealth()
/secrets	POST	Create secret	HandleCreateSecret()
/secrets/:id	GET	Load secret page	HandleLoadSecret()
/secrets/reveal	POST	Reveal secret	HandleRevealSecret()
/opaque/register/start	POST	Start OPAQUE registration	HandleOpaqueRegisterStart()
/opaque/login/start	POST	Start OPAQUE login	HandleOpaqueLoginStart()

Background cleanup job

Backend runs a cleanup worker (startCleanupWorker in app/cmd/api/main.go) that, upon startup and then every 3h, invokes CleanupExpiredSecretsUseCase. The job queries SecretRepository for all records whose expires_at has passed, and for each, deletes both metadata and the blob from storage. Errors are logged, but the remaining expired secrets continue to be deleted to prevent accumulation of "dead" records in the database.