{
 "schema_version": 1,
 "generated": "2026-10-23",
 "id": "vllm-project-vllm--generate-structured-json-outputs",
 "repo": "vllm-project/vllm",
 "repo_url": "https://github.com/vllm-project/vllm",
 "repo_slug": "vllm-project-vllm",
 "title": "Get structured JSON output from a self-hosted model",
 "page_title": "How to get structured JSON output from a self-hosted model with vLLM",
 "summary": "Constrain model replies to a schema so downstream code can parse them reliably.",
 "who": "A data or backend engineer whose pipeline needs machine-readable fields from an LLM, not free text.",
 "problem": "Free-form model replies break parsers, so each extraction job needs fragile post-processing.",
 "outcome": "Model responses that follow a requested structure, ready for direct parsing.",
 "steps": [
  "Install vLLM with `uv pip install vllm`.",
  "Start a served model with `vllm serve <model-id>`, as described in the Quickstart. (inferred, check the README)",
  "Enable structured output using the xgrammar or guidance backend as described in the official documentation. (inferred, check the README)",
  "Send a request that includes your JSON schema and a sample input.",
  "Parse the reply with a JSON parser and check that every required field is present."
 ],
 "agent_prompt": "Using the vllm-project/vllm repo, set up a served model <model-id> with structured output enabled. Send the sample input <sample-text> with a JSON schema and return the parsed object. Verify that the output parses as JSON and contains every required field.",
 "agents": [
  "any"
 ],
 "difficulty": "Advanced",
 "time": "1 hour 30 minutes",
 "basis": "readme",
 "caveat": "The README names xgrammar and guidance but does not show how to enable them, so the exact option must come from the official docs.",
 "category": "Software and DevOps",
 "tags": [
  "Software and DevOps"
 ],
 "lang": "python",
 "requirements": [
  "Python with uv or pip installed",
  "A supported NVIDIA, AMD or Intel GPU, or an x86, ARM or PowerPC CPU",
  "A Hugging Face model you are allowed to download and use"
 ],
 "risk": "none",
 "seen_in_the_wild": false,
 "mentioned_publicly": false,
 "risks": [],
 "best": false,
 "score": 0.9,
 "evidence": [],
 "url": "https://dedupedai.com/use-cases/vllm-project-vllm/generate-structured-json-outputs/",
 "md": "https://dedupedai.com/use-cases/vllm-project-vllm/generate-structured-json-outputs/index.md",
 "disclaimer": "Deduped lists open-source repositories that belong to other people. We do not own, maintain, audit, or vouch for any of them, and a repo appearing here is not an endorsement or a safety check. The use cases, steps, and prompts are written by AI and may be incomplete, outdated, or just wrong. Where a use case is marked \"Seen in the wild\", we link to public posts where someone described something similar, but we have not verified those posts and the use case itself is still our AI's own write-up. Use all of this at your own risk. Only run code, commands, or agents on systems and accounts you are authorized to use, and read the code and every command before you run it, especially anything that touches credentials, files, or the network. Nothing here is professional, security, legal, or financial advice. All trademarks and project names belong to their respective owners, and their use here does not imply affiliation. Content is provided as is, without warranties of any kind. Found a mistake, a safety problem, or something you want removed? Email hello@dedupedai.com and we will look at it promptly.",
 "api": "https://dedupedai.com/api/v1/usecases/vllm-project-vllm--generate-structured-json-outputs.json",
 "api_version": "v1"
}