JSON Schema Validator — Free Online Tool Validate JSON locally against common JSON Schema rules including types, required properties, arrays, enums, ranges, lengths, and patterns.
Use this free online JSON Schema Validator directly in your browser. No signup required, no data leaves your device. Part of Utilier — a collection of 133+ developer utilities.
What is JSON Schema Validator? JSON Schema is a declarative format for describing the expected structure and constraints of JSON data. It can state which properties are required, which types are accepted, and rules such as allowed values, string lengths, numeric ranges, and patterns.
Path-specific errors: Reports the property or array element where a document does not satisfy the schema.Core constraints: Supports types, required properties, object properties, arrays, enums, ranges, lengths, patterns, and additional-property rules.Offline checks: Validates pasted schema and document data in the browser without making an API request.Why use JSON Schema validator? JSON can parse successfully while still failing an API contract. Validating a payload locally catches structural mistakes before a request is sent and gives clearer feedback than a generic server-side validation error.
When to use JSON Schema validator Use it while designing request bodies, validating configuration files, testing documentation examples, or checking a schema before integrating an API. The tool intentionally supports a practical core subset rather than every keyword from every JSON Schema draft.
How to use JSON Schema validator Paste a schema: Describe the expected object, fields, and constraints.Paste JSON data: Provide the document you want to verify.Review paths: Use the returned paths to correct missing, mistyped, or disallowed values.Examples Required property Schema requires name and age; document omits age.$: required property "age" is missing.Minimum value age: -1 with minimum: 0$.age: must be at least 0.Frequently asked questions Is this a complete JSON Schema implementation? No. It covers common structural constraints and does not claim full draft-specific coverage.
Does it modify my JSON? No. It only evaluates the provided document.
Can I use it for API payloads? Yes. It is especially useful for checking a request body before sending it.
Privacy and availability Runs entirely in your browser — zero server processing No signup or account required Works offline once loaded Fast, lightweight, no external dependencies Available as a browser extension for Chrome and Firefox Tags JSON HTTP CI/CD API Related tools JSON Beautifier & Validator — Format, minify and validate JSON. Reports the exact error location.JSONPath Query — Query JSON data using JSONPath expressions ($, dot notation, arrays, wildcards, recursive descent).API Tester — Lightweight REST, GraphQL & WebSocket client with auth, body types, query params, and request history.JSON to TypeScript — Convert JSON objects to TypeScript interfaces. Handles nested objects, arrays, and optional/null fields.All developer tools JSON Beautifier & Validator — Format, minify and validate JSON. Reports the exact error location.HTML Beautifier & Minifier — Indent or minify HTML. Content of pre/script/style is preserved.CSS Beautifier & Minifier — Pretty-print or minify CSS. 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