JSON Schema Validator
Validate JSON payloads against standardized JSON Schemas (AJV compilation).
Configure inputs and click Run
How It Works & Educational Guide
How Nexifr's JSON Schema Validator handles your data securely in the browser — covering supported formats, encoding standards, and practical developer workflows.
01Validate JSON Data Against a Schema
A JSON Schema describes the shape of valid JSON: which properties are required, what values are allowed, and how nested objects and arrays should look. Paste the schema and a JSON payload, then run the validator to see whether the payload conforms and where an error occurs.
02JSON Syntax Errors vs Schema Validation Errors
A syntax error means the JSON itself cannot be parsed, often because of a missing quote, comma, or bracket. A schema validation error means the JSON is valid text but does not meet the rules in the supplied schema, such as a missing required field or an unexpected value type. Fix syntax first, then use the validation errors to update the payload or schema.
03Use Safe Test Data
Validation runs in the browser with Ajv. Even so, use redacted examples rather than production secrets, credentials, or personal data when testing a schema in any browser-based tool.
Frequently Asked Questions
Which JSON Schema drafts are supported?
This validator supports JSON Schema Draft 4, Draft 7, and Draft 2020-12 — the three most widely used versions. The schema is compiled using Ajv (Another JSON Validator), the most widely adopted JSON Schema implementation for JavaScript. The correct draft is detected automatically from the $schema field in your schema definition.
What is the difference between a JSON syntax error and a schema validation error?
A syntax error means the JSON text itself is malformed and cannot be parsed — caused by a missing quote, misplaced comma, or unclosed bracket. A schema validation error means the JSON is structurally valid text but does not conform to the rules defined in the schema, such as a missing required field, wrong data type, or value outside a defined enum. Fix syntax errors first; once the JSON parses cleanly, address schema validation errors.
What is AJV (Another JSON Validator)?
Ajv is the most widely adopted JSON Schema validator for JavaScript. It compiles schemas into optimised validation functions for high performance, supports all major JSON Schema drafts, and produces detailed error messages that identify exactly which property failed and why. This tool uses Ajv compiled and run entirely in your browser — no server is involved.
Is it safe to paste my JSON data into this validator?
Validation runs entirely in your browser using Ajv — no data is sent to any server. Even so, use redacted or anonymised test data rather than production credentials, API keys, personal information, or secrets when testing schemas in any browser-based tool.
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