JSONStructured OutputAPI DesignReliability

Getting Structured JSON Output from LLMs

Techniques to ensure LLMs return valid, structured data suitable for programmatic consumption.

Why Structured Output Matters

Production applications need predictable, parseable responses. Direct LLM outputs are often inconsistent.

Using Response Format

// Request with JSON mode
curl https://chinawhapi.com/v1/chat/completions \
  -d '{
    "model": "qwen-plus",
    "messages": [{"role": "user", "content": "Extract user info"}],
    "response_format": {"type": "json_object"}
  }'

Prompt Engineering for Structure

Include examples in your prompt. Specify exact field names and types expected in the output.

Validation & Fallback

Always validate JSON responses. Implement retry logic with stricter prompts if parsing fails.