JSON Formatter & Viewer
Beautify, minify, validate and sort JSON with syntax highlighting and a collapsible tree viewer. Pinpoints errors by line and column.
Runs in your browser — your data never leaves your deviceFormatted JSON will appear here.
How to use JSON Formatter & Viewer
- 1
Paste or upload JSON
Paste JSON into the editor, upload a .json file, or load the sample to try it out.
- 2
Format, validate or minify
Pick 2 spaces, 4 spaces or tabs, sort keys, or minify. Errors show the exact line and column.
- 3
Explore and export
Switch between highlighted code and a collapsible tree, then copy or download the result.
Frequently asked questions
Is my JSON sent to a server?
No. Formatting, validation and the tree viewer all run in your browser with JavaScript, so API responses, configs and tokens never leave your device. You can even use the page offline once it has loaded.
How do I find the error in invalid JSON?
The status bar shows a plain-English message with the exact line and column, plus an excerpt with a caret under the problem. Click "Go to error" to jump the cursor there. Common causes are trailing commas, single quotes, unquoted keys and comments — none of which are allowed in strict JSON.
What does "Sort keys" do?
It reorders the keys of every object alphabetically, at every nesting level, while keeping array order unchanged. This makes two JSON documents much easier to compare and produces stable, diff-friendly output.
Can it handle large JSON files?
Yes — files of several megabytes work well. Parsing is debounced while you type, the tree renders lazily (100 items at a time), and syntax highlighting switches off for very large output to keep scrolling smooth. Note that numbers beyond 2^53 lose precision in JavaScript, as with any browser-based tool.