Skip to tools
JSON Toolbox- Free online JSON tools

JSON Schema Validator

Paste your schema on the left and data on the right to validate. Instant feedback with paths and clear error messages.

  • 100% client-side, nothing uploaded
  • Instant results
  • Works offline once loaded
JSON Schema

11 lines · 283 chars

JSON Data

5 lines · 71 chars

Valid — data matches the schema

How it works

About this tool

This free online JSON Schema validator checks whether a JSON document conforms to a JSON Schema. Use it to verify API payloads, config files, and form data against a contract before they hit production.

Paste the schema and the data into the side-by-side editors. Validation updates as you type: a success banner when everything matches, or a detailed list of failing paths and messages when it does not. Both panels also catch JSON syntax errors with line and column reporting so you can separate “invalid JSON” from “valid JSON that fails the schema.”

The validator is aimed at draft-07 style schemas you can paste in full. Prefer bundled schemas over remote references when you need everything to stay local and private.

Validation is powered by Ajv and runs entirely in your browser. Your schema and data never leave your device.

JSON Toolbox processes all data locally in the browser. Nothing is uploaded to a server.

Common questions

Frequently asked questions

How do I validate JSON against a schema online?
Paste a JSON Schema on the left and your JSON data on the right. Validation runs automatically as you type. A green success state means the data matches; otherwise you get a list of paths and messages for each issue.
Which JSON Schema draft is supported?
The validator uses Ajv with JSON Schema draft-07 semantics by default. Common keywords such as type, properties, required, additionalProperties, minimum, maximum, pattern, and items are supported for everyday API and config contracts.
What is the difference between a JSON validator and a schema validator?
A JSON validator checks that text is syntactically valid JSON. A schema validator also checks that the structure and types match a JSON Schema — for example that email is present and age is a non-negative integer.
Are remote $ref schemas fetched automatically?
This tool is built for self-contained schemas you paste locally. Remote $ref resolution over the network is not the default, which keeps validation private and offline-friendly. Inline or bundled schemas work best.
Is my schema or data uploaded?
No. Schema validation runs entirely in your browser. Neither the schema nor the data is sent to a server, logged, or stored.

Keep exploring

More JSON tools

Browse all