C4 — Component

C4Component
    title Component view of the Auth service
    Container_Boundary(auth, "Auth service") {
      Component(controller, "Auth Controller", "Node.js", "Handles HTTP requests")
      Component(jwt, "JWT Service", "Node.js", "Issues + validates tokens")
      Component(hasher, "Password Hasher", "Argon2id", "Hashes + verifies passwords")
      Component(repo, "User Repository", "Postgres", "Persists user records")
    }
    System_Ext(api, "API Gateway", "Routes inbound traffic")
    SystemDb_Ext(pgsql, "Postgres", "Primary user database")
    Rel(api, controller, "Calls", "HTTPS")
    Rel(controller, jwt, "Uses")
    Rel(controller, hasher, "Uses")
    Rel(controller, repo, "Uses")
    Rel(repo, pgsql, "Reads + writes", "JDBC")