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JSON Schema Validator

Validate JSON against a JSON Schema.

beats jsonschemavalidator.net edge: Inline error paths + draft-07
schema
data
enter schema and data
Guide

About JSON Schema Validator

Validate JSON against a JSON Schema. Paste the schema and the sample; get a list of errors with the exact path and constraint violated. Supports draft-07 keywords (type, properties, required, items, enum, pattern, minLength, maxLength, minimum, maximum, ...). Useful for testing API contracts, config validation, and data pipeline gates.

Where JSON Schema fits

A schema is a contract. Producers commit to producing JSON that matches; consumers verify on receipt. Used for:

  • API request/response validation (OpenAPI uses JSON Schema)
  • Config files (Kubernetes manifests, GitHub Actions YAML)
  • Database column shapes (Postgres jsonb constraints)
  • Test fixtures (validating sample data matches expectations)

When the schema is shared, both sides can iterate independently while preserving compatibility.

What this validator does

  1. Parses the schema for syntax.
  2. Parses the sample for syntax.
  3. Walks the sample against the schema, recording every constraint violation.
  4. Renders a sortable error list with paths.

Common errors:

  • Missing required field — required declared a key that is absent
  • Wrong type — type: "string" but value is a number
  • Out of range — maximum: 100 but value is 1000
  • Pattern mismatch — pattern: "^https" but value starts with http://
  • Enum violation — value not in enum: [...]

Common workflows

Validate an API contract. Paste your service’s response schema and a real response. Pass → contract holds. Fail → fix one side.

Audit a Kubernetes manifest. k8s schemas are public. Pull the schema for Deployment, validate your manifest against it before applying.

Test a data pipeline. Schema-validate every record at ingestion. Reject broken records loudly, not silently.

Verify form output. Front-end serializes form to JSON, validate against schema before submit. Cleaner errors than backend rejection.

Why local validation

Schemas often describe sensitive shapes — internal API contracts, credit card processors, auth tokens. Validating remotely leaks those shapes. Browser-side keeps the schema and sample local.

Frequently asked questions

Which draft is supported?
Draft-07 by default — most-deployed in production. Draft 2020-12 keywords ($dynamicRef, prefixItems) work in toggle mode.
Why use JSON Schema over Zod / Yup?
JSON Schema is language-agnostic — the same schema validates across Node, Python, Go, Ruby. Zod and Yup are TypeScript-specific. Pick by where the data flows.
How are errors reported?
Each error includes the JSON Pointer path (/users/0/email), the failed keyword, and the expected vs actual values. Click an error to highlight the offending value in the source.
Can I generate a schema from JSON?
Not in this tool — try JSON to Zod or JSON to TypeScript for inferred schemas. JSON Schema generation usually needs domain knowledge the inference cannot capture.
Are external <code>$ref</code> URLs fetched?
No. We resolve in-document #/... refs but skip external URLs to keep the validator local-only. Inline external schemas before validation.
Best practice for big schemas?
Split into multiple files referenced by local $ref; bundle for runtime use. The tool validates the bundled form.

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Last updated: 2025-01-15