Choosing an AI Provider
Modmixer uses an AI model to write your mod. You bring your own access (an API key or an existing AI subscription) and Modmixer connects to it.
Recommended: OpenRouter + Kimi K2.6
OpenRouter is a pay-as-you-go AI model provider. You add credit to your account and pay per request, with no monthly subscription. Kimi K2.6 is currently the best price/performance pick for modding. It's strong at multi-file code generation at a fraction of the cost of Opus or GPT-5.5.
Sign up, add credit, paste your API key into Modmixer.
Using a Claude or ChatGPT subscription
If you already pay for Claude Pro / Max or ChatGPT Plus / Pro, you can use that instead. Opus and GPT-5.5 are the strongest models available today and can produce almost any mod you can imagine.
A note on ClaudeAnthropic changed its policy so that third-party apps can no longer draw from your included Claude Pro / Max usage. Instead requests are billed against the more expensive "extra usage" bucket. Modmixer is not currently affected by this change, but policies can shift, so check that your Modmixer usage is coming from your subscription to avoid an unexpected bill.
Other providers
Modmixer also supports GitHub Copilot, Google Gemini, and Google Antigravity. They appear in the model picker once you sign in. Use them if you already have access.
Still not sure?
Sign up for OpenRouter, add $5 in credit, pick Kimi K2.6.