How to Validate JSON

Aug 16, 2026

Syntax validation catches broken JSON before an API client does. Schema checks are a separate step.

Syntax is not schema

A document can be valid JSON and still be the wrong shape for your API. First confirm the text parses. Then check field names against your contract.

Use a local validator

The JSON Validator runs JSON.parse in the browser. You get a clear error for illegal tokens. Nothing is stored.

Common failures:

  • Trailing commas in objects or arrays
  • Comments, which JSON does not allow
  • Single-quoted strings
  • Unescaped newlines inside strings

After it parses

Beautify the same payload with the JSON Formatter so reviewers can see nested objects. If you started from YAML, convert it first.

What this page does not do

DNVERSE does not evaluate JSON Schema, OpenAPI examples, or database constraints. Those belong in CI. Syntax validation is the fast local gate.