JSON Schema Generator

How it works

How to use the JSON Schema Generator

1. Paste sample JSON

   The more representative the sample, the better the schema. Arrays of objects are merged to find optional fields.

2. Tune the options

   Pick the draft, how "required" is decided, whether to detect formats, and whether to forbid extra properties.

3. Refine and use

   Copy the schema into your validator, OpenAPI spec or form library and add constraints like minimum or pattern.

How the schema is inferred

Every value in the sample is analysed. Objects in the same array are merged, so a property missing from some items is not marked as required. Numbers that are always whole become integer. Mixed types become type unions (e.g. ["string", "null"]). Strings that look like dates, emails, URLs, UUIDs or IPv4 addresses get a format.

Built for developers

Why developers use it

• Private by design

  Runs 100% in your browser. Nothing you paste is uploaded, logged or stored on a server.

• Instant results

  Output updates as you type, with precise error locations when something is wrong.

• Works offline

  Once loaded, the tool keeps working without a connection. Install it as an app if you like.

• Free, no sign-up

  No accounts, no limits, no watermarks.

FAQ

Frequently asked questions

Keep going

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