> ## Documentation Index
> Fetch the complete documentation index at: https://docs.crazyrouter.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Structured Outputs

> Production-verified structured JSON output with the latest GPT and Gemini models

> Дата обновления: 2026-06-06

# Structured Outputs

This page only documents Structured Output flows that were **verified with real requests against Crazyrouter production**.

Verification date:

* `2026-03-22`

Strictly verified models:

* `gpt-5.5`
* `gemini-3.1-pro`

Not included as a strict-success example:

* `claude-opus-4-8`

Reason:

* Under the current OpenAI-compatible `response_format=json_schema` request shape, `claude-opus-4-8` did not show stable strict-JSON behavior across production checks
* Earlier testing produced JSON wrapped in Markdown code fences
* The `2026-03-22` recheck returned empty `content`
* Because the result is not stable or strictly parseable, it is not treated as a verified strict structured-output success example

## Verified matrix

| Model            | Protocol                | Endpoint                                      | Success marker                          |
| ---------------- | ----------------------- | --------------------------------------------- | --------------------------------------- |
| `gpt-5.5`        | OpenAI Chat Completions | `POST /v1/chat/completions`                   | Response can be parsed directly as JSON |
| `gemini-3.1-pro` | Gemini Native           | `POST /v1beta/models/{model}:generateContent` | Returns JSON text matching schema       |

## GPT-5.4

```bash theme={null}
curl https://api.crazyrouter.com/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "gpt-5.5",
    "messages": [
      {
        "role": "user",
        "content": "Return a JSON object with keys city and country for Tokyo."
      }
    ],
    "response_format": {
      "type": "json_schema",
      "json_schema": {
        "name": "city_country",
        "strict": true,
        "schema": {
          "type": "object",
          "properties": {
            "city": { "type": "string" },
            "country": { "type": "string" }
          },
          "required": ["city", "country"],
          "additionalProperties": false
        }
      }
    }
  }'
```

Verified production output:

```json theme={null}
{"city":"Tokyo","country":"Japan"}
```

## Gemini 3 Pro

```bash theme={null}
curl "https://api.crazyrouter.com/v1beta/models/gemini-3.1-pro:generateContent?key=YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [
      {
        "role": "user",
        "parts": [
          {
            "text": "Return a JSON object with keys city and country for Tokyo."
          }
        ]
      }
    ],
    "generationConfig": {
      "responseMimeType": "application/json",
      "responseSchema": {
        "type": "object",
        "properties": {
          "city": { "type": "string" },
          "country": { "type": "string" }
        },
        "required": ["city", "country"]
      }
    }
  }'
```

Verified production output:

```json theme={null}
{"city":"Tokyo","country":"Japan"}
```

## See Also

* [OpenAI Structured Output](/ru/chat/openai/structured-output)
* [Gemini Document Understanding](/ru/chat/gemini/document)