2026-08-31
Pasting a wall of minified JSON into a formatter is one of the most common things a developer does in a browser tab, so it's worth knowing what your options actually do with that data — and how good they are at telling you what's wrong when the JSON is broken.
| Tool | Runs fully in your browser | Account required | Auto-fixes common issues (trailing commas, single quotes) | Tree view |
|---|---|---|---|---|
| iLoveDevTools | Yes | No | Yes | Yes, interactive |
| JSONFormatter.org | No (server round-trip) | No | Partial | Basic |
| JSONLint | No (server round-trip) | No | No — strict validation only | No |
The JSON Tools page formats, validates, and minifies in one place, and it will fix the most common reasons pasted JSON fails to parse — single quotes instead of double, trailing commas — before showing you a real error if the content is still broken. Everything happens client-side, so nothing you paste is sent anywhere, and the interactive tree view is useful once you're past formatting and actually trying to find a specific field in a large payload.
A solid, no-frills formatter that's been around a long time. It gets the basic job done — paste, format, copy — but doesn't attempt to repair malformed JSON, and formatting happens via a server request rather than locally.
More of a strict validator than a formatter. If you want to know exactly why your JSON is invalid down to the line and column, JSONLint is thorough about it. It won't pretty-print with the same tree-navigation convenience, though.
If you're validating a single payload and want the strictest possible error messages, JSONLint is fine. For everyday formatting, especially messy JSON copied out of logs or a debugger, iLoveDevTools's auto-fix and tree view save the most time — and it's the only one of the three that never sends your data over the network.