JSON Formatter
Format, validate, and minify JSON instantly in your browser.
What you can do
Readable JSON in one click
Real-time validation
Detects syntax errors with the exact line number so you can fix them quickly.
100% private
Your JSON is processed in your browser. API data never leaves your device.
Format or minify
Choose human-readable indentation for debugging or compact minification for production.
Instant
Formatting happens in milliseconds regardless of JSON size.
How it works
Three steps, no hassle
Paste your JSON
Enter or paste the JSON string you want to format. Can be an API response, a config file, or any JSON text.
Format or minify
Click 'Format' for indented, readable JSON, or 'Minify' to strip whitespace and reduce file size to a minimum.
Copy or download the result
Use the copy button to send the result to your clipboard. Syntax errors are highlighted with the exact line number.
FAQ
Got questions?
Valid JSON must follow RFC 8259: object keys must be double-quoted strings, values can be strings, numbers, booleans (true/false), null, arrays, or objects. Trailing commas and comments are not allowed in standard JSON.
Formatting adds line breaks and indentation to make JSON human-readable. Minifying does the opposite: it removes all unnecessary whitespace to reduce file size. Minifying is useful in production to cut the weight of API responses or config files.
No. The formatter validates JSON against the standard and shows where the error is (line and character number), but it does not attempt to guess or auto-correct the author's intent. Automatic fixes on malformed JSON could silently introduce incorrect data.
The tool runs in your browser, so the practical limit is determined by available memory. For typical API JSONs (up to several megabytes) performance is excellent. Extremely large documents (tens of MB) may slow down the browser tab.
JSONC is an unofficial extension of JSON that allows single-line (//) and block (/* */) comments, plus optional trailing commas. It is used by config files like TypeScript's tsconfig.json. Standard JSON does not support comments, so this tool validates pure JSON per RFC 8259.
JSON formatter: how to read and debug API responses
JSON (JavaScript Object Notation) is the most widely used data interchange format on the web. All modern REST APIs return responses in JSON, and most software project configuration files use this format. However, APIs typically return minified JSON — with no line breaks or spaces — that is impossible to read directly.
Formatting JSON adds hierarchical indentation that lets you see the document structure at a glance: which fields exist at the root level, what nested objects it contains, and what data types each field holds. This visualization is essential for debugging API integrations, understanding responses from external services, and reviewing complex configuration files.
Convertir.ai formats and validates JSON directly in your browser using the native JavaScript engine. This means processing is instant and your data — which may include authentication tokens, customer data, or other sensitive API information — is never sent to any external server.