Responses

POST /v1/responses

Auth: routing key (pllm_…). Codex and OpenAI lanes get the Responses body natively; other lanes are translated through chat completions and translated back.

Request body

Field	Type	Notes
model	string, required	Same values as chat completions.
input	string or array, required	A string, or Responses items: message, function_call, function_call_output.
instructions	string	System prompt.
stream	boolean	Server-sent events with Responses API event lines.
tools	array	Function tools. Only type: "function" translates to non-native lanes; other tool types are dropped there.
tool_choice	string or object	Forwarded.
text.format	object	json_object and json_schema supported.
temperature, top_p, max_output_tokens	number	Forwarded.
metadata	object	Echoed back.
previous_response_id	-	Not supported. Returns 400 unsupported_feature; resend the full conversation in input.

curl https://api.proxyllm.ai/v1/responses \
  -H "Authorization: Bearer pllm_your_routing_key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "flagship",
    "input": "Say hello."
  }'

Response

The standard Responses object. Trimmed to the fields most callers read:

{
  "id": "resp_4f8d2c9a...",
  "object": "response",
  "created_at": 1751500000,
  "status": "completed",
  "error": null,
  "model": "flagship",
  "output": [
    {
      "id": "msg_a1b2c3...",
      "type": "message",
      "role": "assistant",
      "status": "completed",
      "content": [
        { "type": "output_text", "text": "Hello!", "annotations": [] }
      ]
    }
  ],
  "usage": {
    "input_tokens": 9,
    "input_tokens_details": { "cached_tokens": 0 },
    "output_tokens": 3,
    "output_tokens_details": { "reasoning_tokens": 0 },
    "total_tokens": 12
  },
  "metadata": {}
}

Tool calls appear in output as function_call items with call_id, name, and arguments. With "stream": true the body is text/event-stream carrying Responses API events (response.output_text.delta, response.completed, and so on).

Errors

Status	Code	When
400	(none)	model or input missing, or input is empty.
400	unsupported_feature	previous_response_id was sent.
400	no_providers	The key has no lanes.
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.
502	upstream_error	All lanes failed.

Full list: error codes.