JSON Schema Validator Online
Validate JSON data against a JSON Schema instantly. Get detailed error messages with JSON Pointer paths showing exactly where validation fails. All processing happens in your browser -- your data never leaves your device.
Supports Draft-07 and Draft-04 schema keywords
Schema & Data
Paste your JSON Schema definition
Paste the JSON data to validate against the schema
How to Use This JSON Schema Validator
Paste Your Schema
Enter your JSON Schema definition in the first text area. The schema describes the expected structure, types, and constraints of your data.
Paste Your Data
Enter the JSON data you want to validate in the second text area. This is the data that will be checked against your schema rules.
Click Validate
Hit the Validate button to check your data. You will see a green pass or red fail with detailed error messages including JSON Pointer paths.
How JSON Schema Validation Works
Schema + Data → Validate Rules → Pass / Fail with ErrorsJSON Schema validation works by traversing the data structure and checking each value against the corresponding schema rules. The validator recursively descends into nested objects and arrays, collecting all violations along the way.
Step 1: Parse both the schema and data as JSONStep 2: Check type constraints (string, number, object, array, etc.)Step 3: Validate value constraints (min, max, pattern, format, etc.)Step 4: Check structural rules (required, additionalProperties, items)Step 5: Report all errors with JSON Pointer pathsSupported schema keywords in this tool:
- Type validation -- type, enum, const
- String rules -- minLength, maxLength, pattern, format (email, uri, date, date-time, ipv4, ipv6, uuid)
- Number rules -- minimum, maximum, exclusiveMinimum, exclusiveMaximum, multipleOf
- Array rules -- items, minItems, maxItems, uniqueItems
- Object rules -- properties, required, additionalProperties, minProperties, maxProperties
This tool processes everything client-side in your browser. No data is ever sent to a server, making it safe for sensitive schemas and data.
Frequently Asked Questions
What is JSON Schema?
JSON Schema is a vocabulary for annotating and validating JSON documents. It describes the expected structure, data types, and constraints of JSON data. Think of it as a blueprint that defines what valid JSON data looks like for your application, API, or configuration file.
Which JSON Schema drafts does this tool support?
This tool implements a practical subset of JSON Schema Draft-07 and Draft-04 keywords including type, required, properties, items, minLength, maxLength, minimum, maximum, pattern, format, enum, const, uniqueItems, additionalProperties, and more. It covers the most commonly used validation rules for everyday schema validation.
Is my data safe when using this tool?
Yes. All validation happens entirely in your browser using JavaScript. Your JSON schema and data are never sent to any server. Nothing is logged, stored, or transmitted. You can verify this by using the tool offline after the page loads.
What is the difference between JSON Schema Draft-04 and Draft-07?
Draft-07 introduced several improvements over Draft-04, including the "if/then/else" conditional keywords, "const" for exact value matching, "contentMediaType" and "contentEncoding" for string content, and boolean schemas. Draft-07 also clarified "exclusiveMinimum" and "exclusiveMaximum" to be numeric values rather than boolean flags.
Can I validate nested objects and arrays?
Yes. This validator fully supports nested validation. Use "properties" to define schemas for object fields, "items" to validate array elements, and nest these as deeply as needed. Error messages include JSON Pointer paths (e.g., /address/city) so you can locate issues in complex nested structures.
Privacy Notice
This JSON Schema validator runs entirely in your web browser. Your schema and data are never uploaded, stored, or processed on any server. All validation logic uses standard browser JavaScript. You can safely use this tool with sensitive schemas, API specifications, or proprietary data structures.