JSON Drift

JSON Schema Validator

Validate JSON documents against a JSON Schema.

  • 100% client-side · your data never leaves your browser
  • Instant, no rate limits
  • Free, no sign-up
JSON document
JSON Schema

Click validate to check the document against the schema.

Overview

JSON Schema Validator — Validate JSON Online

Validate JSON documents against a JSON Schema in your browser. JsonDrift reports every failing path, validation keyword, and human-readable message — so you can fix API payloads, config files, and LLM structured outputs before they hit production. Syntax validation only checks parseability; schema validation checks the contract your consumers rely on.

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  1. Syntax vs schema validation

    Valid JSON can still be wrong: a string where an integer was promised, a missing required field, or an enum value outside the allowed set. Schema validation catches contract violations that syntax checks miss — the difference between 'parses' and 'correct'.

  2. Supported validation keywords

    • type — string, number, integer, boolean, array, object, null
    • properties and required — object shape and mandatory keys
    • enum and const — allowed literal values
    • items — array element schemas
    • minItems / maxItems — array length bounds
    • minimum / maximum — numeric constraints
    • Nested objects validated recursively

  3. API and CI workflows

    Paste a failing production payload alongside the schema your service published. Each error path maps to a field in your code or docs. In CI, validate golden fixtures against the same schema before deploy to catch breaking API changes early.

  4. Validating LLM structured output

    Models tasked with JSON output often drift: extra keys, wrong types, truncated arrays. Define a JSON Schema for the expected tool result, validate every response, and retry or repair when validation fails. Pair with our JSON Validator for syntax and this tool for structure.

  5. Privacy

    Schemas and payloads stay on your device. Validate customer data, internal configs, and security-sensitive API samples without sending them to a cloud validator.

FAQ

Frequently asked questions

Which JSON Schema version is supported?

Common keywords used in OpenAPI and Draft-style schemas. Complex $ref resolution across external files may need dedicated tooling.

Does this replace the JSON syntax validator?

No. Use the JSON Validator first for syntax; use this tool for schema rules.

Can I validate YAML?

Convert YAML to JSON first, then validate the JSON document against your schema.

Is validation done on a server?

No. Validation runs entirely in your browser.

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