JSON Schema generator — infer a schema
Paste sample JSON and get a JSON Schema (draft 2020-12) inferred from its structure. It generates in your browser (0 uploads, works offline).
How to use it
- Paste your input into the left pane.
- Choose any options above the panes.
- The result updates live on the right — Copy or Download it.
FAQ
How do I generate a JSON Schema from JSON for free?
Paste a JSON sample and a JSON Schema appears instantly in your browser with no upload — types are inferred (including integer vs number), object properties become schema properties, and every present field is marked required.
What draft of JSON Schema is this?
Draft 2020-12, the current version, declared via the keyword. The output validates in standard JSON Schema tools.
Is my JSON uploaded?
No. The inference is local and nothing is stored; it works offline.
Can I edit the result?
Yes — the generated schema is a starting point. Loosen the required list, add formats or descriptions, and constrain values by hand as needed.
Limits
Infers from one sample, so all present fields are marked required. Formats, patterns and value constraints are not inferred.
Related
The JSON-to-TypeScript tool infers TS types; the JSON schema validator (coming soon) checks payloads.
Bookmark this page (Ctrl+D, or ⌘D on Mac) or install the app — it works offline the next time you need it.