Developer Tools
JSON Schema Validator Online Free
Validate JSON against schema rules for APIs, configs, and webhooks. Check required fields, types, enums, and patterns privately in your browser — no signup.
Free · Runs in your browser · No signup · Files stay on your device
Paste the schema that defines your JSON contract, required fields, allowed values, and API validation rules.
Quick examples
Paste the request body, response body, or config JSON you want to validate against the schema.
Quick examples
How to use
How to use JSON Schema Validator Online Free
- 1Paste or edit a JSON Schema in the first text area.
- 2Paste the JSON data you want to test in the second text area.
- 3Click Validate JSON Schema to compare the data with required fields, types, enums, patterns, and other schema rules.
- 4Review the result and fix any required fields, types, unexpected properties, or validation mismatches.
Tips
Quick tips
- Use this when you need to validate JSON against schema rules, not just confirm the payload parses.
- If the schema or payload came from logs, docs, or chat, clear syntax problems in /developer-tools/json-validator before running schema validation.
- Open either editor in fullscreen mode when you need to inspect long API payloads or large schemas.
- Set additionalProperties to false when you want schemas to reject unexpected fields.
- Schema validation is ideal for API payloads, config files, webhook samples, and contract checks before deployment.
FAQ
Frequently asked questions
How do I validate JSON against a schema online?
Paste the JSON Schema into the schema editor, paste your JSON data into the data editor, and click Validate JSON Schema. The tool checks required fields, data types, enums, patterns, and other schema rules entirely in your browser.
How do I check JSON schema online?
Paste your schema and JSON data, click Validate JSON Schema, and review required, type, enum, and pattern errors. This is the fastest way to check JSON schema rules directly in the browser.
Is this the right tool for JSON validation schema checks?
Yes. Use this page when you need to validate JSON against a schema definition rather than only checking whether the JSON syntax is valid.
Can I validate a JSON object against a schema online?
Yes. Paste the JSON object or payload into the data editor, paste the schema into the schema editor, and run validation to see whether the object matches required fields, data types, enums, and other schema rules.
How is JSON schema validation different from JSON validation?
JSON validation checks syntax only. JSON schema validation checks whether valid JSON also follows structural rules such as required fields, data types, enums, and minimum values.
Can I use this as a schema JSON validator for API payloads?
Yes. Paste the schema that defines the payload contract and the request or response body you want to test. Validation happens entirely in your browser, which makes it useful for contract checks before deployment.
What does this JSON schema validator check?
JSON Schema rules like required, minimum, maximum, enum, pattern, array items, and additionalProperties are supported through Ajv so you can check both structure and value constraints.
Is my schema or data uploaded anywhere?
No. Schema compilation and validation run locally in your browser.
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