JSON Schema Generator
Generate a JSON Schema from a JSON sample
What is JSON Schema Generator?
This generator infers a draft 2020-12 JSON Schema from sample data: it tells integers apart from floats, annotates recognisable strings with email, uri, date and date-time formats, and can optionally mark every field it encounters as required. Inference runs locally in your browser.
How to use JSON Schema Generator
- 1Paste a sample payload that covers as many fields as possible.
- 2Give the schema a title, and turn off "mark fields as required" if you do not want it.
- 3Copy the schema for request validation or documentation.
- 4Review the required list and numeric ranges by hand — a sample cannot express business constraints.
Frequently asked questions
Why is additionalProperties: false added by default?+
It makes the schema reject any field it does not declare, which surfaces misspelled keys early during integration. If your API needs to stay forward compatible and accept new fields, change it to true or delete the line.
Can I use the generated schema for validation in production?+
Treat it as a skeleton and add the business constraints yourself: minLength and pattern for strings, minimum and maximum for numbers, and enum lists where the value set is fixed. Sample data can only tell you the type of a field, never its range of valid values.
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