Formateur JSON
Formatez, validez et minifiez votre JSON instantanément.
Free online JSON Formatter and Validator
Formatting JSON displays it with readable indentation and validates its syntax. FileSwiftly formats, validates and minifies your JSON in real time in the browser — no data sent, 100% local processing.
Format vs Minify JSON
Formatting (pretty-print) indents JSON with spaces and line breaks for maximum readability — ideal for debugging and documentation. Minification removes all unnecessary whitespace to reduce API response size — essential in production to improve load times.
Strict JSON validation
Our validator detects common syntax errors: missing commas, unquoted keys, unescaped special characters, `undefined` values (invalid in JSON), trailing commas. Errors are located with precise line and column numbers.
Developer use cases
Essential for: debugging REST API responses, reading config files (`package.json`, `appsettings.json`), validating data before database injection, or comparing two JSON structures. Paired with our Base64 encoder, it covers 80% of common developer JSON needs.
FAQ
Is my JSON sent to your servers?
No. Formatting and validation are 100% local in your browser via JavaScript. No data is transmitted.
What is the maximum JSON size handled?
Our tool comfortably handles JSON files up to ~10 MB. Beyond that, performance depends on your device's capabilities.
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