JSON Formatter is one of those small Android utilities developers keep installed for a single reason: an API response or a config file lands as one unreadable line, and they need it readable in the next ten seconds. Most of the time that moment happens at a desk, not on a phone, so we built Pretty JSON, a free formatter that runs right here in your browser. Paste your JSON, and it is validated, indented, and color-highlighted before you finish reading this sentence. Broken JSON does not just fail quietly either; it tells you the exact line and column to fix.
Format JSON with Pretty JSON now
Paste or type into the left panel. The right panel updates as you go, and switches to a precise error location the moment something breaks.
How to use it
Paste raw JSON into the left panel, or start typing over the sample data that loads by default. The output on the right reformats on every keystroke, with keys, strings, numbers, booleans, and nulls each colored so nested structure is easy to scan. Pick 2 spaces, 4 spaces, or a tab from the indent menu, or flip the minify switch to collapse everything onto one line for pasting into a config file or a URL.
Tap “Copy” to grab the formatted result exactly as shown, ready to paste elsewhere; that stays a private action and never opens the share menu. If your JSON has a mistake, the output panel is replaced with the exact line and column where parsing failed, plus a “Show me in the input” button that jumps your cursor straight to the broken character. Your last input is saved on your device between visits, so a half-finished paste survives a refresh. Nothing you type is sent anywhere.
How it compares to JSON Formatter
Pretty JSON keeps the part of the Android app people reach for most: paste messy JSON, get it validated and beautifully indented with syntax highlighting, instantly and without a “format” button to press. That loop, paste in and watch it snap into shape, is the whole point, and we built the error reporting to match what a developer actually needs: not just “invalid JSON” but the specific line and column to go fix.
The full JSON Formatter app goes further. It adds collapsible sections for folding large objects and arrays out of the way, line numbers down the side, in-document search with match highlighting, an edit mode with arrow-key navigation for restructuring data by hand, and an automatic backup system that keeps previous versions of whatever you were working on. It also supports pinch-to-zoom for reading dense JSON on a small screen and follows your device’s dark mode.
We left out collapsing, search, and backups on purpose. Those are the tools you want for exploring a large file you did not write yourself, which is a native-app job with real file access. Pretty JSON is built for the smaller, more frequent task: you have a blob of JSON right now, on whatever device you’re using, and you need it readable or minified in the next few seconds. For quick checks and reformatting, this page is faster than opening an app. For working through a large exported file over time, install JSON Formatter.
Get the full app
JSON Formatter is free on Android, with collapsible sections, line numbers, in-document search, an editable view, automatic backups, and dark mode support for reading and restructuring larger JSON files on your phone.
Frequently asked questions
Can I format JSON online without downloading anything?
Yes. Pretty JSON runs entirely in this page. Paste your JSON and it is validated and indented live, with no install and no account required.
Is this the official JSON Formatter app?
No. Pretty JSON is an original tool we built, inspired by the quick paste-and-format job that JSON Formatter does well. It is not affiliated with, endorsed by, or connected to its developer. For collapsible sections, search, and backups on larger files, get the official app from the stores above.
Does it tell me exactly what’s wrong with invalid JSON?
Yes. Instead of a generic “invalid” message, the output panel shows the exact line and column where parsing failed, along with a plain-language reason, and a button that jumps your cursor straight to that character in the input.
Can I minify JSON, not just format it?
Yes. Flip the Minify switch and the output collapses to a single compact line with no extra whitespace, ready to paste into a config value or a URL parameter. Switch it back to see the indented version again.
Does Pretty JSON work offline?
Yes. Once the page has loaded, formatting and validating JSON keeps working without a connection. Your last input is saved in your browser’s local storage on your device only.
Is it free?
Yes, completely free with no signup and no limit on how much JSON you format.
