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Cifrivo
Developer

JSON validator

Answer one question quickly: is this JSON syntactically valid? Get a clear result plus the error line, column and a useful hint.

Processed locallyYour files never leave your device.

Everything is processed locally in your browser.

How it works

  1. Paste JSON or select a .json file.
  2. Press Validate JSON.
  3. Read the valid result or use the reported line and column to locate the syntax problem.
  4. Correct the input and validate again.

Practical example

{"name":"Ada",} fails because JSON forbids a trailing comma. The validator identifies the parser location instead of silently changing the input.

Formula and explanation

A JSON validator checks syntax, not whether the values satisfy your application's business rules. Valid JSON may be an object, array, string, number, boolean or null. Whether particular keys are required needs a JSON Schema or application-specific check.

Frequent errors include single quotes, unquoted property names, comments, missing commas, trailing commas and unclosed brackets. The validator retains the original text so you can compare the parser message with the exact source.

Validation runs entirely in the browser with the native standards-compliant parser. Nothing pasted into the editor is included in Analytics or transmitted to Cifrivo.

Frequently asked questions

Does valid JSON have to start with an object?

No. Any JSON value is valid at the top level, including an array, string, number, boolean or null.

Does this validate JSON Schema?

No. It checks JSON syntax. Schema validation additionally checks required properties, types and other domain rules.

Are comments allowed in JSON?

No. Standard JSON supports neither // nor block comments. Formats such as JSON5 use different rules.