Data · free local utility

JSON Schema Validator

Test a JSON instance against a schema and trace each failure to the data path and schema rule that produced it.

Use the tool

Paste a JSON instance and schema, then select Draft 2020-12 or Draft 7. The validator does not fetch remote $ref resources.

Worked example

See the input and expected result

Example input

Instance: {"age": 16}; schema requires integer age >= 18

Expected result

Invalid · /age must be >= 18 · schema path #/properties/age/minimum

How it works

Get a useful result in three steps

Paste valid JSON data and a JSON Schema.
Select the matching draft and validate.
Fix path-level errors and re-check in the production validator.

Accuracy boundary

A focused tool, not an automatic expert

Remote $ref resolution and custom formats are disabled. Schema validity does not prove business correctness, authorization, or API compatibility.

Always verify the result in the system where you will use it. The page intentionally avoids accounts, uploads, and claims that go beyond the calculation it performs.

Questions

Before you use the result

Which drafts are supported?

Select Draft 2020-12 or Draft 7. A schema from another draft can use different keywords or semantics.

Does format validate email, URI, or date-time?

Common ajv-formats checks are enabled, but formats are useful validation hints rather than proof that a resource exists or is safe.

Can the schema load a remote $ref?

No. The page deliberately refuses network resolution. Bundle referenced schemas locally or use your application validator.

Related tools

Continue the task locally

Browse every json & data tools in this workflow.