What does a JSON Schema validation error actually mean?

Each error reports the instance path (where the problem is, e.g. `/users/0/email`) and a message naming the rule that failed (e.g. `must match format "email"`). Follow the path into your JSON, then check that field against the matching part of the schema.

Which draft should I use — Draft-07, 2019-09, or 2020-12?

Check the `$schema` property at the top of your file — it names the draft the file was written for. Starting from scratch, Draft-07 is the safest default with the widest tool support, while 2020-12 is the current spec and adds features like unevaluatedProperties.

Does this JSON Schema validator work without an account?

Yes. Everything runs client-side via Ajv. No data is transmitted, no sign-up, and no daily limit on how many times you validate.

What are the most common JSON Schema validation errors?

Missing required properties, wrong types (a string where a number or object was expected), format mismatches like invalid emails or dates, and plain JSON syntax errors. Fix syntax errors first — the validator can't compile a schema check until both documents parse.

Can I validate JSON5 or JSON with comments here?

No. The tool follows the strict JSON spec (RFC 8259), so JSON5 extensions like trailing commas or comments will fail to parse before schema validation even starts. Convert to standard JSON first.

JSON Schema Validator

Free online JSON Schema Validator — validate JSON data against any schema (Draft-07, 2019-09, 2020-12) instantly in your browser. No install, no sign-up.

Updated April 2026

Shift + Enter to Copy · Shift + Del to Clear

JSON Data

EDITABLE

JSON Schema

How this JSON Schema validator works

Two editors, one clear result

1. Paste your JSON and schema

Drop the data document on the left and the schema rules on the right, then pick the draft version from the dropdown.

2. Validate

Click Validate, or just wait — it also re-checks automatically a moment after you stop typing.

3. Read the result

Green means valid. Red lists every failing rule with the exact path in your data, so you know exactly what to fix.

What this JSON Schema validator does

Three drafts, one validation engine

Draft-07, 2019-09 and 2020-12

Pick the version that matches the $schema property declared in your own file.

Exact error path for every failure

Each violation shows the instance path (e.g. /users/0/email) and the exact rule that failed — no guessing which field is wrong.

Beautify on both panels

Format the JSON data and the schema with 2-space indentation in one click, on either side.

Ajv engine, 100% local

The schema is compiled and validated entirely in your browser using Ajv — nothing is uploaded anywhere.

Examples

What a validation error actually tells you

Validation error

What it means

/users/0/email — must match format "email"

the email field doesn't match the expected pattern

/age — must be integer

a field expected as integer contains a string instead

root — must have required property 'name'

a required property is missing from the data

When you'll reach for this tool

The most common scenarios among people who use it

API contract testing

Validate request and response payloads against an OpenAPI schema before writing integration tests.

Config file sanity check

Confirm a package.json or CI/CD config file is well-formed before committing it.

Pipeline quality gate

Reject records that violate a schema before they land in a database or a message queue.

Form data validation

Draft a schema for user-submitted data and check it server-side without hand-rolled field checks.

SDK and API development

Publish a canonical schema so consumers can validate requests locally before calling your API.

Getting a validation error? Start here

Missing required field

A property listed in required isn't present in the data at all.

Wrong data type

A field expected as integer contains a string, for example — or an array where an object was expected.

Format violation

A field with "format": "email" or "format": "date" doesn't match that pattern, even though its type is correct.

JSON syntax error

The validator can't run schema checks until both documents parse as valid JSON — fix the syntax error first, then re-validate.

Why validate here

Everything runs in your browser with the Ajv library — no data is ever sent to a server, no account, no login, no usage limit.

Every error comes with its exact path in the document, so you skip the manual work of scanning a large payload field by field to find what broke.

Quick Tools vs. manual checking

Same check, very different effort

Quick Tools

Manual checking

Supports Draft-07 / 2019-09 / 2020-12

yes

depends on the library chosen

Exact error path

yes

manual

No dependency to install

yes

Nothing sent over the network

yes

depends

Frequently asked questions

Paste the document into the "JSON Data" editor and the schema into the "JSON Schema" editor, then click Validate. The tool compiles the schema with Ajv and checks the data entirely in your browser — no server call, no upload.

Resources

json-schema.org

The official JSON Schema specification and documentation.

Ajv

The validation library that powers this tool.

Understanding JSON Schema

A friendly guide explaining every keyword with examples.