What Is an OpenAI-Compatible API? How It Works and Why Every AI Tool Supports It

If you've used any AI coding tool in the past year, you've used an OpenAI-compatible API — whether you knew it or not. Claude Code, Cursor, Aider, Continue, Cline, LangChain, LlamaIndex — they all speak the same protocol. Here's what that means and why it matters for your stack. The Standard An "OpenAI-compatible API" is any HTTP endpoint that accepts the same request format as OpenAI's Chat Completions API: curl https://any-provider.com/v1/chat/completions \ -H "Authorization:...