# Structured output

> Ask for JSON with response_format, either JSON mode or a JSON schema, and which providers and routes honour it.

Source: https://digitspace.ai/docs/api/structured-output · Last checked: 2026-10-31

Use `response_format` on `/v1/chat/completions`, exactly as with OpenAI.

Python:

```python
reply = client.chat.completions.create(
    model="auto",
    messages=[{"role": "user", "content": "Name a city and its country."}],
    response_format={
        "type": "json_schema",
        "json_schema": {
            "name": "place",
            "strict": True,
            "schema": {
                "type": "object",
                "properties": {"city": {"type": "string"}, "country": {"type": "string"}},
                "required": ["city", "country"],
                "additionalProperties": False,
            },
        },
    },
)
```

TypeScript:

```ts
const reply = await client.chat.completions.create({
  model: "auto",
  messages: [{ role: "user", content: "Name a city and its country." }],
  response_format: {
    type: "json_schema",
    json_schema: {
      name: "place",
      strict: true,
      schema: {
        type: "object",
        properties: { city: { type: "string" }, country: { type: "string" } },
        required: ["city", "country"],
        additionalProperties: false,
      },
    },
  },
});
```

## Which models are used

- **`json_schema`:** routing only sends the request to offers marked as supporting structured output. With `auto`, that narrows the choice; with a named model that has no such offer, you get `400 capability_mismatch`.
- **`json_object` (JSON mode):** routing doesn't check for it. It's passed to OpenAI-format providers. Anthropic-format providers and AWS Bedrock have no JSON mode; there it's dropped and the model answers as it would without it.

> **Warning:** `response_format` is dropped when a request is translated to Anthropic's or Bedrock's format. If you send `json_object` to a Claude model, ask for JSON in the prompt as well, and parse defensively.

On `/v1/messages` there is no `response_format`; use a tool with an input schema, the usual way to get structured output from Anthropic's API.