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JSON Schema Validator

Check JSON data against a schema and receive a bounded list of issues with instance paths, keywords, and explanations.

  • Runs locally
  • Local $ref
  • Up to 10,000 nodes
Online tool

Try the tool

Add your data, choose the settings, and get the result.

Instance and schema

Validation result

Run validation to produce a report.

Your data stays here

Text and selected files are processed in the current browser and are not sent to a server to produce the result.

Reviewed: 2026-07-17
01

How to use it

  1. 1

    Paste the JSON instance.

  2. 2

    Paste the JSON Schema.

  3. 3

    Run validation and review paths and keywords in the report.

02

What the tool can do

  • type, enum, const, properties, required, and additionalProperties.
  • items, min/max items, uniqueItems, and object/string/number constraints.
  • allOf, anyOf, oneOf, not, $defs/definitions, and local JSON Pointer $ref.
  • Bounded checks for date, date-time, email, uri, uuid, IPv4, IPv6, and hostname formats.
03

Common use cases

  • Checking API fixtures and configurations.
  • Diagnosing required and additional properties.
  • Running a quick local check before a CI validator.
04

How it works inside

Input is limited to 500,000 characters, 10,000 nodes, and depth 64.

The report is limited to 100 validation issues and marks truncation when the limit is reached.

05

Questions and answers

Are remote $ref values supported?

No. The tool resolves only local JSON Pointer references inside the supplied schema and makes no network requests.

Does this replace Ajv or a standards-complete validator?

No. Use a standards-complete validator in CI when your project depends on the full JSON Schema vocabulary.