JSON Schema Validator

Validate a JSON document against a JSON Schema online. Errors are listed clearly, in your browser.

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About JSON Schema Validator

JSON Schema Validator checks a JSON document against a JSON Schema and lists every rule it breaks — missing required properties, wrong types, values outside allowed ranges, strings that do not match a pattern, and more. Paste the schema on the left and the data on the right.

Validation is done with Ajv, the most widely used JSON Schema validator, using draft-07 rules, and formats such as email, date, date-time, uri, uuid and ipv4 are checked too. Everything runs locally in your browser — the text you paste is never uploaded.

How to use JSON Schema Validator

  1. Paste your JSON Schema on the left (or click Sample).
  2. Paste the JSON data to check on the right.
  3. Validate and read the list of errors, or the confirmation that the data is valid.

Key features

  • All errors listed, not just the first
  • Format checks: email, date, uri, uuid, ipv4…
  • Powered by Ajv
  • Draft-07 JSON Schema

Example

The email has no domain ending and the age is below the minimum, so both rules are reported.

Schema / data
Schema:
{"type":"object","required":["name","email"],"properties":{"name":{"type":"string"},"email":{"type":"string","format":"email"},"age":{"type":"integer","minimum":18}}}

Data:
{"name":"Asha","email":"asha@example","age":16}
Result
data/email must match format "email"
data/age must be >= 18

When to use JSON Schema Validator

  • Checking API request and response bodies against a contract.
  • Validating configuration files before deployment.
  • Testing a schema while you write it.

Tips and common problems

  • Add "required" to list properties that must exist — otherwise missing fields pass.
  • Set "additionalProperties": false to reject unexpected fields.
  • Use "format" (email, date, uri) for common string formats; they are checked too.

Frequently asked questions

A JSON document that describes what other JSON must look like: which properties exist, their types, which are required and what values are allowed. It is used to validate API requests, config files and data imports.