JSON Formatter & Validator
Format, validate, and minify JSON. Shareable URLs. Entirely in your browser.
Best for developers debugging API responses, reviewing config files, or sharing a pre-filled JSON snippet with a teammate.
How it works
Paste or upload
Paste text into the input box, or click the file button to load a .json file.
Set options
Adjust formatting or conversion options to match your needs.
Output appears instantly
Results update as you type. Everything runs locally in your browser.
Copy or download
Copy the output to clipboard, or download it as a file.
Frequently asked questions
It parses your JSON and re-serialises it with consistent indentation, making it easy to read. If your JSON has a syntax error, it shows you the exact line and column where the problem is.
No. The formatter runs entirely in your browser using JavaScript. Your JSON never leaves your device — there are no uploads, no logging, and no accounts required.
2-space indent is the most common choice in JavaScript codebases. 4-space is preferred in many Python and Java projects. Tab indentation uses a literal tab character (\t), which allows each developer to set their preferred display width in their editor.
When enabled, every object's keys are sorted alphabetically before output. This is useful for comparing two JSON objects (diffing), committing config files to version control, or producing consistent output regardless of the original key order.
Minification removes all unnecessary whitespace — newlines, spaces between tokens — producing the most compact valid JSON string. Use this before putting JSON into HTTP responses or config files where size matters.
Yes. Your input is encoded in the URL hash (the part after #) as you type. Copy the URL from your browser's address bar to share a link that will automatically fill the input when opened.
Common causes: trailing commas ({"a":1,} is invalid JSON), single-quoted strings (only double quotes are valid), unquoted keys ({name:"value"} is not JSON), comments (JSON does not support // or /* */), and missing commas between items.
There is no hard limit — it is bounded by your browser's available memory. Files up to tens of megabytes format instantly. Very large files (>100 MB) may slow the browser tab during parsing.