Text & dev
JSON Formatter & Validator
Paste raw or messy JSON and clean it up in one click: Format rewrites it with tidy two-space indentation, Minify strips every needless space and line break for the smallest possible payload, and Validate checks whether the text is well-formed JSON. When something is wrong — a trailing comma, a missing quote, a stray bracket — you get a plain-English error message and, where the browser provides it, the exact position so you can jump straight to the problem. The tool uses your browser's native JSON engine, the same parser your code runs, so the result matches what your application will actually accept. Nothing is uploaded: your JSON never leaves the page, which makes it safe for API responses, config files and other data you would rather not paste into a random website.
Your JSON
Your formatted or minified JSON will appear here.
Formatting uses 2-space indentation. Validation and parsing use the browser's native JSON.parse.
How the JSON formatter works
Every action runs your text through JSON.parse, the same parser built into your browser and Node.js. If parsing succeeds, the tool has a real JavaScript value in memory. Format then calls JSON.stringify(value, null, 2) to print it back with two-space indentation and one key per line. Minify calls JSON.stringify(value) with no spacing, producing the most compact valid form. Validate parses and reports success without rewriting anything.
What each button does
Format → JSON.parse(text) then JSON.stringify(value, null, 2) Minify → JSON.parse(text) then JSON.stringify(value) Validate → JSON.parse(text) → valid or a positioned errorIf JSON.parse throws, the tool shows the browser's error message and, when available, the character index where parsing failed.
Notes & assumptions
- Standard JSON only: comments, trailing commas and single quotes are invalid and will be flagged.
- Object key order is preserved exactly as parsed by your browser.
- Very large documents are limited only by your device's memory, since everything runs locally.
Frequently asked questions
Why does my JSON say "Unexpected token" or fail to validate?
The most common causes are a trailing comma after the last item in an object or array, using single quotes instead of double quotes around keys and strings, unquoted keys, or a missing closing brace or bracket. Comments (// or /* */) are also not allowed in standard JSON. The error message and position shown by the validator point you to where the parser gave up, which is usually at or just after the real mistake.
What is the difference between Format and Minify?
Format (beautify) adds two-space indentation and line breaks so the structure is easy to read and review in a code editor or pull request. Minify removes all of that whitespace to produce the smallest valid JSON, which is what you want for API payloads, query strings or anything where byte size matters. Both produce exactly the same data — only the spacing differs.
Does this tool change my data or reorder keys?
No. The formatter parses your JSON into a value and prints it back, so numbers, strings, booleans, nulls, arrays and objects are preserved. Object keys keep the order your browser parsed them in, which for typical JSON is the order you wrote them. Only the indentation and whitespace are changed; the meaning of the document stays identical.
Is my JSON sent to a server?
No. The formatter, minifier and validator all run entirely in your browser with JavaScript. Your JSON is never uploaded, stored or logged, so it is safe to paste API responses, configuration files, tokens or other sensitive data. Close the tab and nothing is retained anywhere.
Can I format very large JSON files here?
Yes, within reason. Because all processing happens on your device, the practical limit is your computer's available memory rather than any server cap. Documents up to several megabytes format quickly on a modern machine. Extremely large files may briefly freeze the tab while the browser parses them, but no data is lost.