JSON Formatter
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About this tool
JSON Formatter takes messy, minified, or hand-edited JSON and turns it into clean, indented, human-readable text — or collapses it back into a compact single line for transport. It validates the syntax as you type and points you to whatever is wrong.
Everything runs in your browser using the native JSON engine, so even large payloads are processed instantly and your data never touches a server. You can switch between 2-space and 4-space indentation, escape or unescape a JSON string, and toggle line numbers to make deep structures easier to scan.
Because it uses the same parser as your code, what validates here is exactly what your application will accept.
How to use
- Paste or type your JSON into the input box.
- Choose Format (2 or 4 spaces) to indent it, or Minify to collapse it to one line.
- If the JSON is invalid, read the error message — it points to the problem.
- Copy the result, or use Escape / Unescape when you need JSON embedded inside a string.
Common use cases
- Reading and debugging API responses that arrive minified
- Cleaning up configuration files before committing them
- Shrinking JSON to the smallest size before sending it over the network
- Spotting a missing comma or bracket that breaks a parser
Frequently asked questions
Is my JSON sent to a server?
No. Formatting, validation and minifying all run locally in your browser — your data never leaves your device.
What's the difference between formatting and minifying?
Formatting adds indentation and line breaks for readability; minifying strips all unnecessary whitespace to produce the smallest valid JSON for transport.
Why does it say my JSON is invalid?
Common causes are trailing commas, single quotes instead of double quotes, unquoted keys or mismatched brackets. The error points to where the problem is.
Can it handle large JSON files?
Yes. Parsing happens locally with your browser's native engine, so multi-megabyte payloads format almost instantly without any upload.
What do Escape and Unescape do?
Escape converts JSON into a form safe to embed inside another string by escaping its quotes and special characters; Unescape reverses that. It helps when one JSON value itself contains JSON.