100% in your browser · nothing uploaded · no sign-up
Online Json Formatter Viewer
Paste a raw, minified API response and get beautified, syntax-highlighted JSON in under a second — or a precise line-and-column error.
JSON formatter & validator
Type, paste or drop a .json file — the result pane updates live, with no submit step.
Formatting settings
Paste, type, or drop a .json file onto the box. Up to about 2 MB formats automatically.
How it works
Three steps, no submit button, no upload.
Drop in a minified API response, a config file or a small .json file. You can type, paste or drag a file onto the input box.
The browser parses the text on every keystroke and beautifies it with 2 spaces, 4 spaces or tabs. Sorting keys and minifying happen in the same pass, with no server round-trip.
Read the highlighted, line-numbered output, check the stats strip, then copy it to your clipboard or save it as a fresh .json file.
Built for fast debugging
Everything you need to make a broken payload readable — and nothing that gets in the way.
Invalid JSON shows the exact line and column, a snippet with the offending character highlighted and a caret under it, plus a plain-English hint about missing commas or unquoted keys.
Break the document halfway through an edit and the good output stays on screen, so you never lose the readable version you were working from.
Sort object keys recursively in the output only — handy for diffing two responses. Your pasted input is never mutated.
Input size, output size, key count, maximum nesting depth, output line count and the measured parse time, refreshed on every change.
No upload, no account, no tracking request. The page keeps working after load, even with the network switched off.
Inputs over 2 MB pause auto-formatting with a warning, so a huge paste can never freeze the tab. You decide whether to format anyway.
FAQ — frequently asked questions
Is my JSON uploaded anywhere?
No. Parsing, formatting, highlighting and copying all run in your browser with JavaScript. The page makes no network request after it loads, so the data you paste never leaves your device.
How large a payload can I format?
Anything up to about 2 MB formats automatically and usually finishes well under 200 ms. Above that the tool shows a warning and waits for you to press “Format anyway”, then turns off heavy highlighting for very large documents.
What is the difference between Format, Minify and Validate?
Format pretty-prints the document with your chosen indentation. Minify removes insignificant whitespace and writes one compact line. Validate keeps the readable output while focusing on the verdict, the error location and the document stats.
Does it check JSON Schema or duplicate keys?
It validates JSON syntax, which is what usually breaks a copied API response. Schema validation and duplicate-key detection are out of scope — this tool is about making valid-but-unreadable data readable, fast.
Does it work on a phone or offline?
Yes. On narrow screens the split view becomes Input and Output tabs with a sticky Format / Minify / Copy bar at the bottom, and the output pane scrolls on its own instead of the page. Once loaded, the page needs no network at all.
Nothing to install, nothing to trust
Open the page, paste, read. The tool is a single static page with no backend logic and no data retention.