JSON Validator & Formatter

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About this app

JSON Validator & Formatter checks your JSON syntax instantly. Paste or type JSON, or open a .json file, and see right away whether it is valid. If there is a problem, you get a detailed error message with the exact line and column, a preview of the faulty line and a button that takes you straight to the error.

You can also format and beautify JSON with 2 spaces, 4 spaces or tabs for better readability, or minify it to remove unnecessary spaces. Copy the result with one tap or save it as a file.

MADE FOR LARGE JSON
• Validates files of tens of megabytes (up to 200 MB) with progress and a Cancel button
• Large content is processed in streaming mode, so the app stays responsive
• If something does not fit in memory, you get a clear message instead of a crash

FEATURES
• Automatic validation as you type
• Strict validation following the JSON standard (RFC 8259)
• Clear errors: missing comma or colon, trailing comma, unclosed string, single quotes, invalid numbers and more
• Format with 2 spaces, 4 spaces or tab
• Minify JSON
• Copy or save the result
• Statistics: characters, lines, objects, arrays and depth
• Light and dark mode
• More than 70 languages

PRIVATE AND OFFLINE
Your JSON never leaves your device: everything is processed 100% locally, with no account and even without internet.

Ideal for developers, testers and students who work with APIs, configuration files and data.

Free with ads. Download JSON Validator & Formatter and fix your JSON in seconds!
Validate JSON instantly with exact line and column errors. Format or minify.
Updated on
Oct 19, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • No data shared with third parties
    Learn more about how developers declare sharing
  • No data collected
    Learn more about how developers declare collection

What’s new

First release of JSON Validator! Validate JSON offline, see the exact line and column of each error, and format or minify it with one tap. Supports large files and more than 70 languages.