JSON Schema Validator

Paste schema and data to validate compatibility, then quickly identify type, required-field, and range mismatches. No input is sent to a server.

Status

Runs in your browser. No input is sent to a server.

How to use

Paste schema and data, then click Validate. If NG, inspect path-based errors and fix data or schema.

Notes (this tool)

  • Some keywords such as `$ref` are not supported.
  • Input must be standard JSON (without comments).

About this page

What does this tool do?

Compares JSON data against a JSON Schema object and lists which paths failed and why.

A lightweight validator for API contract checks, sample-data verification, and pre-implementation schema alignment.

Supported keywords (this implementation)

  • type / enum / const
  • required / properties / additionalProperties
  • items / minItems / maxItems / uniqueItems
  • minimum / maximum / exclusiveMinimum / exclusiveMaximum
  • minLength / maxLength / pattern / format (subset)
  • allOf / anyOf / oneOf / not

Practical workflow

  • Paste your schema (draft-style object)
  • Paste target JSON data
  • Run Validate and inspect error list
  • Map failed paths back to your spec and fix

Notes

  • This tool implements a practical subset. Advanced features like `$ref`, `if-then-else`, and `dependentSchemas` are out of scope.
  • Format performs lightweight checks for `email`, `uri`, `uuid`, `date-time`, and `ipv4`.

Referenced specs

  • JSON Schema Validation (IETF)
  • RFC 8259 (JSON)
  • RFC 8927 (JSON Type Definition), for comparison

FAQ

Can results differ from full JSON Schema implementations?

Yes. This tool supports a subset, so schemas relying on advanced keywords like `$ref` may behave differently.

What does the error path represent?

It indicates the failing location, such as `$.user.email`, so you can trace which field violates type or constraints.

References

  1. JSON Schema Specification
  2. RFC 8259
  3. RFC 8927

These links are generated from site_map rules in recommended diagnostic order.

  1. JSONPath Tester — Extract and validate matched paths/values via JSONPath
  2. CSV ↔ JSON Converter — Convert CSV and JSON with selectable delimiter
  3. JSON ↔ YAML Converter — Convert between JSON and YAML with validation
  4. JSON Diff — Compare two JSON documents and show diffs
  5. JSON Formatter — Pretty-print, minify, and validate JSON
  6. JSONC Formatter — Format and validate JSONC (comments/trailing commas)

Data Conversion

Convert and validate JSON/YAML/CSV on one screen