OpenRouter is one OpenAI-compatible API in front of hundreds of models from
many providers. Send `POST https://openrouter.ai/api/v1/chat/completions`
with an OpenRouter API key and a `model` such as `openai/gpt-4o` or
`anthropic/claude-sonnet-4`. Every chat model accepts that same request shape.
Image, video, speech-to-text, and text-to-speech models use their own
endpoints, described in each model's per-model guide below.

> A unified API for every major LLM. One endpoint, hundreds of models, with
> routing, fallbacks, and cost tracking across providers.
