JSON Formatter & Validator - Pretty Print JSON Online
Format, beautify, minify, and validate JSON in your browser. Detailed error positions, configurable indent, sort keys, and one-click copy.
Paste any JSON to instantly pretty-print, minify, or validate it. Syntax errors are reported with line and column. Tweak indent size (2/4/tab), sort keys alphabetically for diffing, or compact to a single line. Everything runs in your browser — your data never reaches a server. Works for JSON returned by any REST API, log files, AWS/GCP configs, and copy-pasted snippets from Chrome DevTools.
How to use
- 1
Paste your JSON
Paste any JSON document into the left panel — a single object, an array, or a string of API output.
- 2
Choose an action
Pick Beautify to format with indentation, Minify to collapse to one line, or Sort to alphabetize keys.
- 3
Fix errors inline
If the input is invalid, the error position is highlighted with line and column — fix and the output updates instantly.
- 4
Copy or download
Use Copy or Download on the right panel. Nothing is uploaded — formatting runs entirely in your browser.
FAQ
Q.Is my JSON sent to a server?
No. Parsing, formatting, and validation all run in your browser. There is no network call.
Q.What does Sort keys do?
It recursively reorders object keys alphabetically. Useful for diffing two JSON files that differ only in key order.
Q.Can I format very large JSON files?
Files up to a few MB work smoothly. Beyond that, the browser tab may slow down — for huge files, use a CLI tool like jq.
Q.What does the indent setting do?
Controls how many spaces are used per indent level when beautifying. Tab uses a literal tab character. Default is 2 spaces (matches Prettier).
Q.Are duplicate keys allowed?
JavaScript's JSON.parse silently keeps the last duplicate, so this tool follows that behavior. The JSON spec does not require duplicate-key rejection.