---
title: "Completions"
canonical_url: "https://meingpt.com/en/docs/api/completions"
language: en
---

# Completions

OpenAI-compatible API endpoints

Our API does not support all parameters offered by OpenAI. Requests are still accepted and processed, but not all parameters are considered.

Supported parameters:

- `model`
- `messages`
- `response_format` (only `{ "type": "json_object" }` or `{ "type": "text" }` — OpenAI's `json_schema` / Strict Structured Outputs is not currently supported)
- `stream`
- `temperature`
- `tools`
- `tool_choice`

Reasoning effort/level (e.g. OpenAI's `reasoning_effort`) cannot currently be set via the API — reasoning models use their default effort level for API requests.

Message `content` must be a plain text string — the API does not currently accept images, files, or other attachments (e.g. `image_url` content blocks) in chat completion requests. To send files or images, use the Assistants Run or Workflow execution API instead.

For schema-validated JSON output without OpenAI's `json_schema` mode, define a tool whose `parameters` are the JSON Schema you want and set `tool_choice` to that function (`{"type": "function", "function": {"name": "..."}}`). The model is then required to call the function with arguments matching the schema — read the JSON from `tool_calls[0].function.arguments` instead of `content`.

Reasoning-tier models use a fixed internal `temperature` and may reject other values. If you get an error with these models, try omitting `temperature` from your request or removing any client-side default.

Not every model you see in meinGPT chat is automatically usable via the API. Which models are enabled for your organization is set by a workspace admin (see [Workspace Configuration](/en/docs/admin-guide/workspace-configuration)).

Call [`GET /models/v1`](/en/docs/api/models) to retrieve the exact list of models enabled for your API key, and use the value from the `id` field verbatim as `model` in your request.

If you send a `model` value that isn't enabled for your organization, the API responds with `403 Forbidden` and an error message of this form:

```json
{
  "status": "error",
  "message": "Model 'your-model-id' is not enabled for this organization."
}
```

This message is distinct from the general 403 error "completions API not enabled for organization" (which affects the entire completions API, not a single model). Free-tier models (currently GPT-5 Nano, API id `gpt-5-nano`) are exempt from this restriction and are always available.

## POST /openai/v1/chat/completions

Create a chat completion

Creates a model response for the given chat conversation. Compatible with OpenAI's chat completions API.

### Parameters

- `parameter`

### Request body

Media types: `application/json`

### Responses

- `200` — Successful response
- `400` — Bad request - invalid input
- `401` — Unauthorized - missing or invalid API key
- `403` — Forbidden - completions API not enabled for organization
- `500` — Internal server error