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JSON Schema Validator - Fast Ajv Testing Online

Validate JSON payloads against JSON Schema 2020-12 without leaving the browser. Toggle Ajv options like type coercion, defaults, and removal of additional properties to mirror production settings.

Ajv 8 validation Error stack with JSON pointer Private, browser only

Validation results

Waiting for input. 
Run validation to see success or error details.

How to validate JSON with this tool

  1. Paste your JSON Schema into the left editor. Include the $schema keyword if you want to document the draft.
  2. Add the JSON you want to validate on the right.
  3. Toggle any Ajv options to match your production service, then press Validate JSON.
  4. Read the result log. Each error lists the JSON pointer, schema keyword, and human readable reason so you can fix or suppress issues quickly.

The validator uses Ajv v8 with the 2020-12 meta schema, the same stack used by many production API gateways. That means you can debug locally before shipping new rules to CI.

Features

Ajv 8 core

Ajv remains the fastest open source JSON Schema validator and supports drafts 2019-09 and 2020-12, so this tool mirrors real world CI choices.

Option parity

Flip switches for type coercion, default application, and cleanup of additional properties to simulate how gateways sanitize requests.

Copyable reports

Share the printed error list or copy the JSON pointer path for bug trackers.

Offline friendly

No payloads leave your device, so you can validate confidential configs and health records in locked down environments.

Use cases

API contract testing

Validate staging payloads before merging API contract changes.

Event validation

Ensure analytics events or webhook notifications stay within expected ranges.

Data migrations

Check exported JSON files before loading them into warehouses or caches.

CI guardrails

Prototype schema updates here before adding the same Ajv settings to CI pipelines.

JSON validator FAQ

Which JSON Schema drafts do you support?

The validator ships with draft 2020-12 by default but can also compile schemas tagged with 2019-09.

Do you support formats like email or uri?

Yes. Ajv includes the formats plugin, so keywords such as format: "email" or format: "uri" are evaluated.

Is there a size limit?

Limits are tied to your browser memory. Multi megabyte schemas are fine, but extremely large inputs can slow down the UI.

Can I export the errors?

Use Copy report to place the formatted error log on your clipboard, then share it with your team.