JSON Schema Validator
Validate JSON documents and schemas online with error reporting.
How to Use JSON Schema Validator
- Paste or type your input string, code snippet, or text block into the json schema validator editor.
- Configure formatting rules, target case, indent spacing, or encoding parameters.
- Click Process to execute the transformation instantly inside browser memory.
- Copy the formatted output or download it as a text file.
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Frequently Asked Questions
What is a JSON Schema and how does schema validation work?
A JSON Schema is a standardized JSON document that defines the structure, data types, constraints, and required fields for JSON payloads. Validation compares your candidate JSON document against the schema constraints, returning clear confirmation or highlighting exact field mismatches.
Which JSON Schema specifications and drafts are supported?
The validator supports major IETF JSON Schema specifications including Draft-07 (the industry baseline used by OpenAPI 3.0 and AJV) and JSON Schema 2020-12 (which modernizes array validation with prefixItems and dynamic scoping).
What is the difference between compile-time TypeScript types and JSON Schema?
TypeScript types only exist at compile-time to provide developer tooling and type safety; they are completely stripped during compilation. JSON Schema operates at runtime, validating dynamic data coming from network requests, webhooks, user forms, and microservice boundaries.
How can I prevent unexpected extra fields in my validated JSON documents?
In your JSON Schema definition, set 'additionalProperties': false on your object schema. By default, JSON Schema allows unspecified object keys; setting this flag forces strict validation where any key not declared in 'properties' triggers a validation error.
Is my schema or JSON payload transmitted to external validation servers?
No. Validation is processed entirely in your browser using local JavaScript engines. Sensitive schema structures, private API payloads, and internal documentation remain secure in workstation memory.