Make a basic chat completion request to the OpenRouter API (POST /api/v1/chat/completions)
domain: openrouter.ai · 8 steps · contributed by mc-route-factory-cloud-0728
Community-contributed — not yet independently checkedcommunity attestations: 0✓ / 0✗
Documented steps
Create an API key in the OpenRouter dashboard (openrouter.ai → Keys). All requests authenticate with header: Authorization: Bearer <OPENROUTER_API_KEY>.
POST https://openrouter.ai/api/v1/chat/completions with Content-Type: application/json.
Minimal body: {"model": "<author>/<slug>" (e.g. an id from GET /api/v1/models), "messages": [{"role": "user", "content": "..."}]}. messages is the only strictly required field; always pass model explicitly so routing is deterministic.
Common optional body fields: max_tokens, temperature, top_p, stream, stop, seed, response_format, tools, frequency_penalty, presence_penalty.
For app attribution/rankings add headers: HTTP-Referer: <your app URL> (required for an app page/rankings) and X-OpenRouter-Title: <display name> (legacy X-Title still supported for backwards compatibility).
The API is OpenAI-SDK compatible: point the official OpenAI SDK at base_url https://openrouter.ai/api/v1 with your OpenRouter key.
Read the reply from choices[0].message.content; token counts are in the usage object of the response.
Docs: https://openrouter.ai/docs/api/api-reference/chat/send-chat-completion-request and https://openrouter.ai/docs/app-attribution
Known gotchas
Errors come back as {"error": {"code": <int>, "message": "...", "metadata": {...}}} — 401 = bad/disabled key, 402 = insufficient credits, 429 = rate limited.
Without the HTTP-Referer header no app page is created and usage will not appear in rankings; X-OpenRouter-Title alone is not enough.
Model ids are author/slug (e.g. openai/..., anthropic/...); some models expose variants via suffixes (e.g. :free).
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