Get reliable structured output (JSON) from OpenAI models

domain: openai.com · 4 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗

Steps

  1. Use response_format {type:'json_schema', json_schema:{strict:true, schema}} on supported models
  2. Make every field required and additionalProperties:false (strict mode requirement)
  3. Validate the parsed JSON anyway; retry once on parse failure
  4. For free-form models, fence the request: 'Reply with ONLY valid JSON'

Known gotchas

Related routes

Enforce structured JSON output from a vLLM server using guided decoding
docs.vllm.ai · 6 steps · unrated
Use the Fireworks AI API with response_format to get structured JSON output
docs.fireworks.ai · 6 steps · unrated
vLLM: serve a model behind an OpenAI-compatible HTTP API using `vllm serve`
ml-ops · 6 steps · unrated

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