Chuizi.AI
Chuizi.AI

Structured Output

Two Modes

JSON Mode

Set response_format to { "type": "json_object" }. The model returns valid JSON, but you do not control the schema. You must instruct the model in your prompt to use the structure you want.

config.json
json
{
  "model": "openai/gpt-4.1",
  "messages": [
    {
      "role": "system",
      "content": "You extract contact info. Return JSON with fields: name, email, phone."
    },
    {
      "role": "user",
      "content": "John Smith, john@example.com, (555) 123-4567"
    }
  ],
  "response_format": { "type": "json_object" }
}

Response:

config.json
json
{
  "name": "John Smith",
  "email": "john@example.com",
  "phone": "(555) 123-4567"
}

JSON Schema Mode

Set response_format to { "type": "json_schema", "json_schema": { ... } }. The model is forced to produce output that validates against your schema. This gives you guaranteed structure.

config.json
json
{
  "model": "openai/gpt-4.1",
  "messages": [
    {
      "role": "user",
      "content": "Extract the product info: iPhone 16 Pro, $999, 256GB storage, available in black and white."
    }
  ],
  "response_format": {
    "type": "json_schema",
    "json_schema": {
      "name": "product_info",
      "strict": true,
      "schema": {
        "type": "object",
        "properties": {
          "product_name": { "type": "string" },
          "price_usd": { "type": "number" },
          "storage_gb": { "type": "integer" },
          "colors": {
            "type": "array",
            "items": { "type": "string" }
          }
        },
        "required": ["product_name", "price_usd", "storage_gb", "colors"],
        "additionalProperties": false
      }
    }
  }
}

Response:

config.json
json
{
  "product_name": "iPhone 16 Pro",
  "price_usd": 999,
  "storage_gb": 256,
  "colors": ["black", "white"]
}

Code Examples

terminal
bash
curl -X POST https://api.chuizi.ai/v1/chat/completions \
  -H "Authorization: Bearer ck-your-key-here" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-4.1",
    "messages": [
      {"role": "user", "content": "Extract: Tokyo, population 14 million, country Japan, continent Asia"}
    ],
    "response_format": {
      "type": "json_schema",
      "json_schema": {
        "name": "city_info",
        "strict": true,
        "schema": {
          "type": "object",
          "properties": {
            "city": {"type": "string"},
            "population": {"type": "integer"},
            "country": {"type": "string"},
            "continent": {"type": "string"}
          },
          "required": ["city", "population", "country", "continent"],
          "additionalProperties": false
        }
      }
    }
  }'

Next Steps