structured JSON output api

If you want an API to return structured JSON output, there are a few common ways to do it:

1. Define a JSON schema

Tell the model exactly what shape you want.

Example:

{
  "name": "Alice",
  "age": 30,
  "tags": ["developer", "python"]
}

2. Use a response format in the API

If you're using an LLM API, request JSON-only output explicitly.

Example prompt

Return only valid JSON. No markdown. No extra text.

Example output

{
  "summary": "User asked about structured JSON output API",
  "intent": "information_request",
  "confidence": 0.92
}

3. Validate the response

Always validate the JSON on your side:

• parse it
• check required fields
• reject malformed output
• retry if needed

4. Use function/tool calling if available

Many APIs support tool/function calling, which is more reliable than free-form JSON.

Example structure:

{
  "tool": "create_user",
  "arguments": {
    "name": "Alice",
    "email": "alice@example.com"
  }
}

5. Example with OpenAI-style structured output

If your API supports structured outputs, you typically provide a schema like:

{
  "type": "object",
  "properties": {
    "title": { "type": "string" },
    "priority": { "type": "string", "enum": ["low", "medium", "high"] }
  },
  "required": ["title", "priority"],
  "additionalProperties": false
}

Then the API returns data matching that schema.

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If you want, I can give you:

1. a Python example
2. a JavaScript example
3. an OpenAI structured output example
4. a JSON Schema template