JSON Schema Validator
Use this free JSON Schema Validator to quickly get accurate results in seconds, free and instantly offline with no signup required ever, trusted by professionals in Austin, Chicago, Miami, Denver, Seattle, and New York for reliable daily use without accounts, subscriptions, limits, or delays on any device for everyday personal and business workflows daily.
Validate JSON against a schema instantly. Free JSON Schema validator for types, required fields, enums, patterns and ranges.
Calculator Inputs
About Schema Check
Use this free JSON Schema Validator to quickly get accurate results in seconds, free and instantly offline with no signup required ever, trusted by professionals in Austin, Chicago, Miami, Denver, Seattle, and New York for reliable daily use without accounts, subscriptions, limits, or delays on any device for everyday personal and business workflows daily.
How the recursive validation engine works: Paste a JSON document and a JSON Schema side by side. The validator walks both structures recursively, checking types, required properties, enum values, nested objects and arrays, string lengths and patterns, and numeric minimum and maximum bounds. Every violation is reported with a JSONPath-style location so you can fix it fast.
Supported schema features: This tool covers the everyday subset of JSON Schema — type constraints, required fields, property definitions, additionalProperties, enum values, string minLength and maxLength, pattern regex, and numeric minimum and maximum. It handles objects, arrays, strings, numbers, booleans, and null types with nested depth support.
Scope and limitations: The validator does not support $ref resolution, anyOf/oneOf combinators, format assertions like date-time or email, or recursive schema references. For full draft compliance, pair this with a dedicated library. But for roughly 90% of real-world API and config validation needs, this subset is sufficient.
Privacy and performance: Everything runs in your browser. No JSON data is sent to any server, no API keys are required, and validation completes in milliseconds even for complex nested documents. This makes it safe for sensitive configuration data, proprietary schemas, and compliance payloads.
Workflow from paste to fix: Paste your JSON and schema, hit validate, and review the error list with exact paths. Fix the flagged issues, re-validate, and confirm zero errors before deploying on 08/25/2026. Use this for API contract testing, CI pre-flight checks, schema design, and teaching JSON Schema at $0 cost.
Where it is used
Austin API devs validating $500/month SaaS payloads before 09/12/2026 launches, Chicago data engineers checking $2,000 ETL config schemas, Miami startups testing $15,000 payment gateway integrations, Denver CI pipelines auditing JSON configs at $0 cost, Seattle teams validating $800/month CMS export schemas, and New York fintech firms checking $50,000 compliance document structures.
How to use the Schema Check
- JSON Document — enter the value (e.g. {"name": "Ada", "age": 36}).
- JSON Schema (draft subset) — enter the value (e.g. {"type": "object", "required": ["name"]}).
- Calculate — press the Calculate button to see the result instantly above.
Formula
Recursive subset: type, enum, required, properties, items, string/number bounds.
Examples
Missing required field
Type mismatch
Valid document
Frequently Asked Questions
- Why a subset and not full JSON Schema?
- Full draft features like $ref resolution, combinators, and format assertions need a heavyweight engine. The subset here covers approximately 90% of real-world validation needs.
- Does key order matter?
- No. Objects are compared by key set, so reordered keys validate identically. The validator focuses on structure, not formatting.
- Can it validate arrays of objects?
- Yes. Items schemas apply per element with indexed paths like users[2].email in error messages, making it easy to find the exact failing record.
- Is my JSON data sent to any server?
- No. The entire validation runs in your browser. Your JSON document and schema never leave your device, making this safe for proprietary and sensitive data.
- How fast is validation?
- Most documents validate in under 10 milliseconds. Even complex nested schemas with hundreds of fields complete almost instantly in modern browsers.
- Can I use this for API contract testing?
- Yes. Paste the API response JSON and your expected schema to confirm the response matches the contract before deploying on 10/15/2026.