Is it safe to use the JSON Formatter online?

Yes — and ours is safer than most. Many free online tools quietly upload your files to their servers to do the work. We don't. Everything happens inside your browser on your own device, so your files never reach the internet. There's no upload step, no server copy, and no way for us (or anyone else) to see what you're working on.

Are my files uploaded to a server?

No. There's no server-side processing here. The whole tool is a tiny app that runs in your browser — we don't even have a server that could receive your files. You can confirm this by opening your browser's network tab while you use the tool: nothing leaves your device.

Do I need to sign up or pay?

No. There's no account, no email collection, no credit card. The tool is free to use as much as you want, on as many files as you want. We're supported by a few unobtrusive ads on the page — not by your data.

What's the size limit?

Bound only by browser memory. We've tested 50 MB JSON files on a typical laptop.

Does it support JSONC (JSON with comments)?

Not yet — we use the browser's strict JSON parser which rejects comments and trailing commas. JSONC support is on the roadmap.

Can I edit the output?

Yes — the output is editable. Edits flow back as if you'd typed them in the input.

JSON Formatter & Validator

Pretty-print, minify, or just validate JSON. Errors show inline so you can fix invalid input. Backed by the browser's native JSON parser — fast and standards-compliant.

Features

Three actions: Pretty (with 2/4/8-space indent), Minify, Validate
Live error messages with line/column hints
Handles arbitrarily large JSON (limited only by browser memory)
Output side is also editable — fix typos right there
Runs entirely in your browser

How to json formatter & validator

Paste your JSON — Drop in any JSON — formatted or minified.
Pick action — Pretty for human reading, Minify for transport, Validate to just check.
Copy result — Click Copy on the output box.

Frequently asked questions

Is it safe to use the JSON Formatter online?: Yes — and ours is safer than most. Many free online tools quietly upload your files to their servers to do the work. We don't. Everything happens inside your browser on your own device, so your files never reach the internet. There's no upload step, no server copy, and no way for us (or anyone else) to see what you're working on.
Are my files uploaded to a server?: No. There's no server-side processing here. The whole tool is a tiny app that runs in your browser — we don't even have a server that could receive your files. You can confirm this by opening your browser's network tab while you use the tool: nothing leaves your device.
Do I need to sign up or pay?: No. There's no account, no email collection, no credit card. The tool is free to use as much as you want, on as many files as you want. We're supported by a few unobtrusive ads on the page — not by your data.
What's the size limit?: Bound only by browser memory. We've tested 50 MB JSON files on a typical laptop.
Does it support JSONC (JSON with comments)?: Not yet — we use the browser's strict JSON parser which rejects comments and trailing commas. JSONC support is on the roadmap.
Can I edit the output?: Yes — the output is editable. Edits flow back as if you'd typed them in the input.