JSON Formatter
Format, beautify, minify, and validate JSON data online for free — with adjustable indentation, key sorting, and clear error messages, instantly inside your browser.
What is a JSON formatter?
A JSON formatter takes minified or messy JSON — the kind returned by an API response, logged to a console, or pasted from a config file — and rewrites it with consistent indentation and line breaks so it's actually readable. It also validates the JSON along the way, pointing out exactly where a syntax error is if the input isn't valid.
It's built for developers debugging an API payload, anyone inspecting a config file, or someone who just needs to shrink a formatted JSON blob down to its smallest size before pasting it somewhere space-constrained.
GuideHow to use it
How formatting and validation work
The input is parsed as JSON, which both validates it and gives a structured value to re-serialize. "Format" rewrites that value with the chosen indent size — 2 spaces, 4 spaces, or a tab — while "Minify" strips all whitespace down to the smallest possible representation. "Sort keys" recursively reorders every object's keys alphabetically, which makes it easier to diff two JSON documents or find a specific field in a large object. If the input isn't valid JSON, the exact error message is shown along with the line and column where the parser stopped.
Why it helpsFeatures & benefits
Why this runs entirely in your browser
JSON payloads often contain API keys, user data, or other sensitive information, so nothing is uploaded. Parsing and formatting run in JavaScript locally in the tab, which means it keeps working offline once the page has loaded and nothing pasted into it persists after the tab is closed.
Common uses
Making an API response readable while debugging, validating a config file before deploying it, minifying JSON before embedding it in a URL or script tag, or sorting keys to make two versions of a JSON document easier to compare.
Frequently asked questions
A few things people usually want to know before trusting the numbers.
Yes. The input is parsed as JSON, so anything that isn't valid shows an error message with the line and column where the problem is.
It recursively reorders every object's keys alphabetically, which is useful for comparing two JSON documents or scanning a large object for a specific field.
"Format" adds consistent indentation and line breaks for readability. "Minify" strips all unnecessary whitespace down to the smallest valid representation.
Yes. Use the upload icon above the input box to load a .json file directly.
No. All parsing and formatting happens locally in your browser. Nothing pasted or uploaded here is sent to a server, stored, or shared.