Format, validate, beautify and minify JSON instantly, with clear error messages, right in your browser.
JSON Formatter cleans up messy or minified JSON into neatly indented, readable code and tells you immediately whether it is valid. Paste any JSON object, array or raw API response and the tool parses it in real time. If there is a syntax error (a missing comma, an extra bracket, a single-quoted string where a double-quoted one is required), you get a precise error message that names the problem and its position, not just a vague "invalid" warning. Valid JSON is beautified instantly, with 2-space, 4-space, tab or minified output to match whatever style your project uses. Everything runs in your browser, so sensitive payloads, API tokens and internal config data never leave your device.
JSON is everywhere: REST API responses, webhook payloads, package.json files, app configuration, database exports and browser network logs. Most of it arrives minified or compressed onto a single line to save bandwidth, and the moment you need to read or debug it, you need to see the structure clearly. Developers use this tool to untangle deeply nested objects quickly: spotting the field buried four levels in that is returning null, confirming a webhook body matches the expected schema, or cleaning up a database export before importing it somewhere else. Product managers, QA engineers and data analysts use it too, whenever they need to inspect an API response, check a payload against acceptance criteria or share readable data in a ticket.
Reviewed by the ToolBrainy Team · Runs entirely in your browser · Last updated July 2026
You can paste any valid JSON: an object, an array, a deeply nested structure, or the raw body copied from a network request, Postman or a browser's DevTools Network tab. If you have a .json file, open it in a text editor, select all, and paste it here. The tool handles any JSON value: objects, arrays, strings, numbers and booleans.
For everyday reading and code review, 2 spaces is the most common choice. Choose 4 spaces if your team's style guide requires it, or Tab if your editor is configured for tab indentation. Switch to Minified when you want the smallest possible version: it strips all whitespace and collapses everything to a single line, reducing payload size for API calls and configuration files sent over the network.
If the status bar shows a red error, it names the exact problem and its position, for example "Expected double-quoted property name in JSON at position 47". Common culprits are trailing commas after the last array item, JavaScript-style comments (JSON does not support them), and single-quoted strings instead of double-quoted ones. Fix the issue and the output updates immediately. When the status bar turns green, use Copy to grab the clean JSON or Download to save it as a .json file.
Your JSON is parsed locally and never uploaded.
See clear syntax errors the moment you paste.
Pretty-print for reading or compact for production.
No signup, no limits and no watermarks, ever.
A Stripe webhook payload arrives as a 4,000-character single line. Paste it, choose 2 spaces, and the nested structure becomes readable in seconds, letting you immediately locate the payment_intent status or the amount buried inside the charge object.
A package.json or tsconfig.json silently breaks your build. Paste the file here and the validator points straight to the issue, usually a trailing comma after the last dependency or a missing closing bracket, so you can fix it without guessing.
Tools like MongoDB Compass and Firestore export collections as JSON with each document on one line. Paste the export, choose 4 spaces, and the structure is immediately clear for review or import into another system.
A configuration object grows to 80 lines during development. Switch to Minified and you get a single compact line ready to embed in a script tag or send as a request body, smaller and faster over the network than the beautified version.
When building or testing an integration with Slack, GitHub or Shopify, you need to confirm the incoming body matches the expected schema. Paste the raw webhook body, format it, and immediately see whether the expected event or metadata field is present and correctly typed.
Pasting examples and watching how the formatter indents nested objects and arrays is one of the fastest ways to understand the syntax: how arrays use [], how objects use {}, and why strings must be double-quoted while numbers and booleans are not.
Say an API hands you this on a single line: {"user":{"id":42,"name":"Ada","roles":["admin","editor"]},"active":true}. Paste it, choose 2 spaces, and every key drops onto its own indented line — you can see at a glance that roles is an array with two entries and that active is a real boolean, not the string "true".
Now the reverse. You've been editing a config object across sixty lines and need it compact for a request body. Switch to Minified and the whole thing collapses to {"cache":true,"ttl":3600,"hosts":["a.example.com","b.example.com"]} — no spaces, no line breaks, ready to drop straight into a fetch call.
And a broken one: {"name":"Ada","roles":["admin",]} looks fine at a glance, but the validator flags the trailing comma after "admin" and points to its position. Delete that stray comma and the status bar turns green.
Yes. This tool is completely free with no signup, no limits and no watermarks. Format and validate as many JSON payloads as you need.
Absolutely. Your JSON is parsed and formatted entirely in your browser using the native JSON engine. Nothing is sent to or stored on any server, so it is safe to use with API tokens, internal configuration data and sensitive payloads you would never want to share with a third party.
Beautify (the 2-space, 4-space and Tab modes) adds indentation and line breaks so every key and value sits on its own line with clear visual nesting. This makes JSON easy to read, review and debug. Minify does the opposite: it strips all whitespace and collapses everything into a single line. You would beautify JSON when reading or debugging it, and minify it when embedding it in code or sending it over the network where file size matters.
The tool uses the browser's strict JSON parser, so it catches all syntax violations: trailing commas after the last item in an object or array, single-quoted strings (JSON requires double quotes), unquoted property keys, JavaScript-style comments, and missing or mismatched brackets and braces. The error message includes the position in the input, so you can find the problem without scanning the whole document.
The most common causes are trailing commas (JSON does not allow a comma after the last item in an array or object, even though JavaScript does) and single quotes around strings or property names. If you copied JSON from a JavaScript source or a tool that uses a relaxed format, these issues appear often. The error message will point to the exact position, making it quick to spot.
Any valid JSON value works: objects, arrays, strings, numbers, booleans and null. If your data is a list of records such as a database export, paste the full array and each item will be formatted with clear indentation. Nested structures of any depth are supported.
No, and that is deliberate. Auto-repair tools guess at what you meant and sometimes change your data in ways you would not notice. This tool points to the exact error instead, so you fix it yourself and stay in control of the payload. In practice most breaks are a single trailing comma or a swapped quote, so the fix takes seconds once you know where to look.
Formatting only adds or removes whitespace — your keys, values and types stay exactly as they were. One thing to know about JSON itself: very large integers beyond about 9 quadrillion can lose precision because the parser reads them as floating-point numbers. If you are handling huge IDs, keep them as strings in the source and they will pass through untouched.
No. The tool preserves the original order of every key exactly as you pasted it. Some formatters alphabetise keys by default, which can make a diff harder to read; this one leaves the structure alone so a before-and-after comparison stays clean.
There is no fixed cap. Payloads of a few megabytes format fine on a normal laptop. Very large exports — tens of megabytes — may pause for a moment while the browser parses them, since everything runs on your own machine, but nothing is truncated and no data is uploaded.
They look almost identical, but JSON is stricter. JSON requires double quotes around every key and string, forbids trailing commas, and does not allow comments or functions. A JavaScript object literal is more relaxed. That gap is exactly why JSON copied out of a .js file often fails validation here — the fix is usually swapping single quotes for double quotes and removing a trailing comma.
Yes to both. Once the page has loaded, the formatting runs in your browser, so it keeps working if your connection drops. It also runs on phones and tablets — handy for checking an API response on the go without opening a laptop.