Jan vs MLX LM

Jan

Apache-2.0, with installers for macOS, Windows and Linux plus Flathub and the Microsoft Store. No release since 0.8.4 on 23 July 2026, while a security fix waits on main.

MLX LM

MIT, with no telemetry found in the source, and the tests passed on the last eight pushes to main. mlx_lm.server has no API key option, answers any origin by default and loads whichever model a request names, and its own docs say it is not recommended for production.

Jan

1. Ask the owner to start the server (Settings, Local API Server) or run jan serve. Nothing listens until then
2. Call http://127.0.0.1:1337/v1 for the app and localhost:6767/v1 for jan serve. The ports differ
3. Read /openapi.json from the running server, not the spec on the docs site, which describes the retired Cortex API
4. Branch on the status code. Error bodies are plain text
5. Keep the bind at 127.0.0.1 on 0.8.4. Trusted Hosts is ignored on 0.0.0.0 until the next release

MLX LM

1. Keep mlx_lm.server on 127.0.0.1 and pass --allowed-origins with the origins you trust. There is no API key, and the default answers every origin
2. Treat any caller as able to load any model. The model and adapters request fields accept any Hugging Face repository or local path
3. Send max_tokens or max_completion_tokens when you need more than 512 tokens, the server default
4. Read errors as {"error": "<text>"} with 400 for a bad field and 404 for a model that failed to load. They are not OpenAI error objects
5. Poll GET /health before the first request. It answers 503 with unavailable when the generation thread has stopped