Phoenix: (Phoenix.Router.NoRouteError) no route found for GET /api/users

Quick fix

Read the commands before running them. Anything that restarts a service, deletes data or changes permissions should be tried on a non-production system first.

# The routes table is the fastest answer, and it prints the real paths
mix phx.routes | grep users

# A scope prefixes everything inside it: this serves /api/api/users
scope "/api", MyAppWeb do
  pipe_through :api
  get "/api/users", UserController, :index    # wrong
  get "/users", UserController, :index        # right
end

# Browsers only issue GET and POST, so delete links need the method override
<.link href={~p"/users/1"} method="delete">Delete</.link>

# A forwarded route or a missing pipeline can hide the match as well
mix phx.routes | grep forward

# In production this becomes a plain 404, so reproduce it with MIX_ENV=dev

How to diagnose Elixir errors

Elixir errors are shaped by the actor model: a GenServer.call timeout does not mean the server crashed, it means the server was busy for longer than the caller was willing to wait. The right question is usually "what is that process doing?" rather than "why did the call fail?". Because supervisors restart failed processes automatically, transient errors can also hide in the logs while the system appears healthy.

If the quick fix above does not resolve it, work through these steps. They apply to this whole class of error, not just to this one message, which is usually what saves the time.

1. Attach to a running node with iex --remsh and inspect the process: Process.info(pid, :message_queue_len). A growing mailbox means the process is the bottleneck.
2. Use :observer.start() to see the supervision tree, process memory and message queues visually.
3. Move long-running work out of handle_call. Use handle_cast, a Task, or a dedicated pool so the GenServer stays responsive.
4. Check restart intensity. A supervisor that exceeds max_restarts takes down its own supervisor, producing a cascade that looks like an unrelated failure at the top.
5. For compile errors in dependencies, run mix deps.compile --force and check that any required native toolchain (make, gcc, erlang headers) is installed.

Tools worth reaching for

• :observer.start()
• iex --remsh
• Process.info/2
• mix deps.tree
• :recon

Authoritative references

Primary documentation for this error, worth reading before applying any fix in production.

📖 hexdocs.pm

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Something missing or wrong?

This entry is maintained by hand. If the fix is out of date, incomplete, or you have a better one, email a correction and it will be reviewed.