JSON Formatter
Format and minify JSON. Runs in your browser, your data never leaves it.
This tool runs in your browser. No data leaves your device.
How It Works
A plain formatter built on JSON.parse and JSON.stringify. The indent size is
configurable (2 spaces, 4 spaces, or tab). For invalid JSON it returns a clear error
message.
Where JSON.parse is strict
JavaScript’s built-in parser follows RFC 8259:
- Keys must be double-quoted.
{name: 'x'}is invalid,{"name": "x"}is valid. - No trailing commas.
[1, 2, 3,]is rejected. - No comments.
// noteor/* ... */is not accepted.
These three are where developers get tripped up most often. If you need them, you’re really using JSON5 or JSONC — this tool is for strict JSON.
Minify vs Format
- Format — for readability. Meaningful in diffs.
- Minify — to shrink payload size. For HTTP bodies or WebSocket frames.
Both represent the same data; the only difference is whitespace.
Privacy
The JSON you paste is processed entirely in your browser. It is never sent to sade.dev’s backend or any other service.