Validate JSON data against any JSON Schema draft instantly in your browser. Human-friendly error messages, no sign-up required.
Built for developers who want fast, private, and accurate JSON Schema validation.
Supports all major JSON Schema versions. The correct version is auto-detected from your schema.
Plain-English error messages with actionable fix suggestions instead of cryptic validator output.
Everything runs in your browser — no server round-trips, no waiting. Results appear instantly.
Your JSON never leaves your browser. No data is sent to any server, ever.
Six curated examples covering common patterns: APIs, configs, e-commerce, conditional schemas, and more.
Validates formats like email, URI, date-time, UUID, IPv4/IPv6, and more via ajv-formats.
Everything you need to know about JSON Schema validation.
JSON Schema is a vocabulary that allows you to annotate and validate JSON documents. It describes the structure, data types, and constraints of your JSON data — similar to how a database schema defines table structures. JSON Schema is widely used for API request/response validation, configuration file validation, and data interchange.
This tool supports all major versions: Draft-07 (the most widely used), 2019-09, and 2020-12 (the latest). The correct version is auto-detected from the $schema keyword in your schema — no configuration needed.
Yes, 100% free with no sign-up, no rate limits, and no usage caps. The tool runs entirely in your browser using JavaScript, so there are no server costs to pass on.
Absolutely. Your JSON schema and data never leave your browser. All validation is performed client-side using the ajv library. No data is transmitted to any server — you can verify this by checking the Network tab in your browser's developer tools.
JSON validation checks whether a string is valid JSON (correct syntax with proper brackets, quotes, and commas). JSON Schema validation goes further — it checks whether valid JSON data conforms to a specific structure defined by a JSON Schema, including data types, required fields, value constraints, and more.
This error means your JSON data contains fields not defined in the schema's "properties" object, and the schema has "additionalProperties": false. Either add the extra fields to the schema's properties, or remove them from your data. If you want to allow any extra fields, set "additionalProperties": true in your schema.
Yes. Include "$schema": "https://json-schema.org/draft/2020-12/schema" in your schema and the tool will automatically use the correct version. It fully supports 2020-12 features like prefixItems, $dynamicRef, and $dynamicAnchor.
The tool validates these formats via ajv-formats: date, time, date-time, duration, email, idn-email, hostname, idn-hostname, ipv4, ipv6, uri, uri-reference, uri-template, iri, iri-reference, uuid, json-pointer, relative-json-pointer, and regex.
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