Here is a (small) tutorial on how to get DeepSeek V4 Flash / DeepSeek V4.1 Flash via Composite

If you go to this page here and make an Composite account, you can go to the models page and copy the slug/name for DeepSeek V4 Flash (deepseek/deepseek-v4-flash-0731:free) OR DeepSeek V4.1 Flash (deepseek/deepseek-v4.1-flash:free). Then, head to the API-keys page and make a key, copy it, put that into your JanitorAI config with (https://composite.lucidity.sh/v1/chat/completions) for the endpoint and the model you want to use in the model selector, and it should work.

You'll need to refresh after saving and swapping to the config otherwise it'll error because of Janitor's CORS. Also note that Composite requires you to have a Discord account, not to join any server but to just prevent abuse

If you find this useful, sharing the guide would help