About FreeBrain
FreeBrain is an API gateway for developers using AI models from Anthropic and OpenAI. One FreeBrain key manages calls through the gateway.
Connect your application
- OpenAI Chat Completions / Responses:
https://api.thefreebrain.com/v1 - Anthropic Messages:
https://api.thefreebrain.com
Choose a model that lists your required endpoint. Claude Code uses Messages; Codex uses Responses. Feature support depends on the selected model and channel.
Understand usage and billing
Calls use a prepaid balance. The console records model IDs, token usage and charges. Review each model’s billing unit before making a request.
Standard input and output token rates for the public Discount Offers group, observed 2026-10-08. Check your account group and current rates in the console before calling a model.