JSON Schema Generator
Generate JSON Schema from sample JSON with draft selection, format detection, and required-field policies.
Tool code processes selected files and entered content in your browser and does not submit them to a TOOLGRID processing endpoint. TOOLGRID measures tool usage, not the content you enter.
- No TOOLGRID input upload
- No account
- Review before copy
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What this tool does
Free JSON Schema generator and JSON to schema tool. Paste a sample JSON object or array and generate draft 2020-12 or draft-07 schema with detected string formats, merged array items, and configurable required handling.
JSON Schema Generator infers a schema from a sample JSON document so you can validate future payloads, generate TypeScript, or document APIs.
Use it as a JSON to schema tool when you have a real API response, webhook payload, config file, event sample, or JSON Lines export and need a structured starting point instead of writing every property by hand.
It merges array element schemas, can infer from multiple JSONL samples, detects common string formats (date-time, email, uri, uuid), and supports draft 2020-12 and draft-07.
The insight cards show detected formats, required and optional key counts, and whether multiple samples were merged. Copy either pretty schema output or a compact schema string depending on your handoff target.
All inference runs in your browser. The sample JSON is parsed locally, the generated schema stays in the page, and you decide what to copy into docs, validators, tests, or editor tooling.
Where this tool earns its place
Paste a representative JSON response and generate a schema your team can review, version, and attach to API documentation.
Generate JSON Schema from real examples before tightening property types, required keys, and format rules for production validation.
Infer a starting schema from real webhook, form, or event data, then tighten required fields and formats before using it in validation code.
What to check before relying on the result
- Performance and maximum practical input size depend on browser memory, device speed, and the structure of the input.
- Review the generated result before replacing or publishing an original file.
Open a nearby browser tool when you need to validate, convert, or reuse the result.
How to use
01Use Cases
Paste a representative JSON response and generate a schema your team can review, version, and attach to API documentation.
Generate JSON Schema from real examples before tightening property types, required keys, and format rules for production validation.
Infer a starting schema from real webhook, form, or event data, then tighten required fields and formats before using it in validation code.
Generate schemas from sample payloads provided by two systems and compare the required keys, nested object shapes, and detected formats.
Tips & Tricks
- 01Validate before copying
If the input parser reports an error, fix the source value first instead of copying a partial result into code, config, or documentation.
- 02Keep secrets local
The tool runs in your browser, but you should still avoid pasting long-lived production secrets into any shared or screen-recorded session.
- 03Use representative samples
A schema generated from one small object may miss optional fields. Paste an array of realistic examples when you want the generator to see more shape variations.
FAQ
02Can I generate JSON Schema from a JSON array?
Yes. Paste an array of objects and the generator merges item shapes so repeated samples can produce a more useful schema.
Can it infer schema from JSON Lines?
Yes. Use JSON Lines mode or Auto mode to parse one JSON object per line and merge the sample shapes into a single generated schema.
What does the smart required policy do?
For arrays, every element schema is merged and only the keys present in every element stay required. For single objects it behaves like 'all required'.
Does it detect string formats?
Yes. Date, date-time, email, uri, and uuid formats are inferred from sample values.
Is my JSON sent anywhere?
Inference runs in this tab. Tool code processes selected files and entered content in your browser and does not submit them to a TOOLGRID processing endpoint. Browser-local processing avoids a TOOLGRID upload path, but it is not a blanket security guarantee.
Which JSON Schema drafts are supported?
The generator can output draft 2020-12 or draft-07, so you can match the validator or documentation system you plan to use.