JSON Schema Validator
Validate a JSON document against a JSON Schema (Draft 07 through 2020-12) and get a precise list of every violation, with the exact path and reason each one failed. Runs fully client-side using Ajv.
Paste your JSON Schema on the left and the JSON document to check on the right. Every validation error lists the exact property path and what rule it broke, so you can fix them one at a time.
JSON Schema
JSON to check
Learn more
What a JSON Schema actually describes
A JSON Schema is itself a JSON document that describes the shape another JSON document must have — which properties are required, what type each value must be, allowed ranges for numbers, patterns for strings, and how deeply nested structures should look. It turns "this API response should have a string id and a positive number price" from a comment in documentation into something a machine can actually check automatically, every time, rather than trusting every producer of that JSON to get it right by hand.
This matters most at integration boundaries — validating a webhook payload before processing it, checking a config file before an application starts, or catching a malformed API response before it causes a confusing downstream error three functions later. A validation failure at the boundary, with an exact error message, is far easier to debug than a null-pointer exception deep inside business logic caused by a field that was silently the wrong type.
Frequently asked questions
Which JSON Schema draft versions are supported?
Draft-07, 2019-09 and 2020-12, auto-detected from the schema's $schema field when present, defaulting to 2020-12 otherwise.
Is my JSON or schema sent to a server?
No — validation runs with Ajv entirely in your browser. Nothing you paste here is transmitted anywhere.
What does the error path mean, like .items[2].price?
It's the exact location in your JSON document where validation failed — here, the price field of the third item in an items array — so you can jump straight to the problem instead of scanning the whole document.