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JSON Schema Validator

Validators

Validate JSON data against JSON Schema specifications.

⚡ Instant🔒 Private, in your browser🆓 Free, no sign-up👥 For developers
Your data never leaves your browser. We do not store inputs.

What JSON Schema Validator does

The JSON Schema Validator checks a JSON document against a JSON Schema definition and reports exactly which fields fail — the wrong type, a missing required property, a value outside an enum or pattern — so API payloads and config files can be confirmed against a documented contract before they're used. Both panels are processed locally in your browser.

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Reviewed by the FreeToolsVerse team · Last updated · How we check our tools

How to use JSON Schema Validator

  1. Paste your JSON Schema into one panel
  2. Paste the JSON data you want to validate into the other
  3. Click Validate
  4. Review the list of validation errors, each pointing to the failing field

Who should use it

Made for developers. Typical uses:

  • Confirming an API request body matches the schema documented in an OpenAPI spec before deploying
  • Checking a configuration file against its schema after a manual edit
  • Debugging why a JSON payload is being rejected by a schema-validating API gateway

Frequently asked questions

Is it free to use?
Yes, completely free.
Is my data uploaded anywhere?
No, both the schema and the data are validated entirely in your browser.
Which JSON Schema keywords are supported?
All standard keywords from JSON Schema Draft-07, 2019-09 and 2020-12, selected automatically from your schema's $schema value (Draft-07 if none is given). That includes type, required, properties, additionalProperties, enum, const, pattern, numeric and length limits, allOf/anyOf/oneOf/not, if/then/else, $ref to definitions inside the schema, and formats such as email, uri, date-time and uuid. Remote $ref URLs are not fetched.
What does a validation error actually point to?
Each error names the specific field or path in your JSON data that failed, along with the rule from the schema it violated.
Can I validate an array of objects against one schema?
Yes, as long as your schema defines an array type with an 'items' schema describing each element.

Learning resources

Explore more in Validators, read the guides and articles, or see how we test our tools.

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