Chat completions

POST /v1/chat/completions

Auth: routing key (pllm_…). Requests run through the key’s lanes in order; if a lane hits a rate limit, an exhausted usage window, or an error, the next lane serves the request.

Codex Hosted accepts the same request shape with its own controls and ignored fields; see Codex compatibility.

Request body

Standard OpenAI Chat Completions fields. The gateway reads these; anything else is ignored:

Field	Type	Notes
model	string, required	A tier (flagship, mini), a provider model (gpt-4o-mini), codex/flagship, or bridge/claude-code. Append #node=<tag> to tag the request for the logs.
messages	array, required	OpenAI message objects, including tool results.
stream	boolean	Server-sent events. Streams only when the first lane is a direct API provider; Codex, Anthropic, and bridge lanes return a complete response instead.
temperature	number	Forwarded.
max_tokens	number	Forwarded.
top_p	number	Forwarded.
response_format	object	json_object and json_schema supported.
tools	array	OpenAI function tools.
tool_choice	string or object	Forwarded.

curl https://api.proxyllm.ai/v1/chat/completions \
  -H "Authorization: Bearer pllm_your_routing_key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "flagship",
    "messages": [{"role": "user", "content": "Say hello."}]
  }'

Response

{
  "id": "chatcmpl-4f8d2c9a-...",
  "object": "chat.completion",
  "created": 1751500000,
  "model": "flagship",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "Hello!"
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 9,
    "completion_tokens": 3,
    "total_tokens": 12,
    "prompt_tokens_details": { "cached_tokens": 0 }
  }
}

When the model calls a tool, message.content is null and message.tool_calls carries the calls, exactly like OpenAI. With "stream": true the body is text/event-stream: OpenAI chat.completion.chunk lines ending with data: [DONE].

Every response carries an x-proxyllm-request-id header; that id is the request’s row in your logs.

Errors

Status	Code	When
400	(none)	model or messages missing.
400	no_providers	The key has no lanes.
400	no_credential	Streaming lane has no saved provider key.
401	signup_required	Missing key, or a raw provider key was sent.
401	invalid_api_key	Unknown or revoked routing key.
402	budget_exceeded	Monthly budget exhausted.
405	(none)	Method other than POST or GET.
502	upstream_error	All lanes failed; message carries the last provider error.

Full list: error codes.