I built JSON Buddy — a privacy-first JSON formatter + CSV/Excel JSON converter that works offline

HAU — Wed, 24 Dec 2025 01:48:30 +0000

Hey everyone — I made a little web tool called JSON Buddy and figured I’d share it here in case it helps someone (and to get some honest feedback).

I do a lot of quick JSON work for APIs/logs/configs, and I kept running into two annoyances:
1) I don’t love pasting sensitive-ish JSON into random sites.
2) I also constantly need to turn CSV/Excel stuff into JSON for testing.

So this is my attempt at a “no drama” tool that just works.

What it does:

Format / prettify JSON
Validate JSON (spot errors fast)
Minify JSON
Convert CSV → JSON
Convert Excel (.xlsx/.xls) → JSON
Optional type inference (numbers / booleans / null)

The main thing: it’s privacy-first.
Everything runs in your browser — no uploads, no accounts, and it even works offline (PWA-style).

Link: https://json-formatter.net

If you try it, I’d really appreciate feedback on:

Does the CSV/Excel → JSON output match what you expect? (headers, empty cells, type inference)
Anything you wish these tools did that most of them don’t?
UI/UX: is anything confusing or too “busy”?

If this kind of post isn’t allowed here, totally fine to remove — just let me know.

OPTIONAL FIRST COMMENT (if you want to add details without making the post too long)
A couple specifics in case it helps:

You can paste CSV/TSV directly (including copy/paste from Excel)
Excel upload supports .xlsx / .xls
Type inference is optional, so you can keep everything as strings if you prefer
It’s meant to be a small offline toolbox, not a SaaS

Happy to tweak/add features if there’s a real need.

DEV Community: HAU

I built JSON Buddy — a privacy-first JSON formatter + CSV/Excel JSON converter that works offline