I've lost count of how many times I've pasted a blob of JSON into a terminal window and tried to make sense of it with python -m json.tool — only to get a cryptic error with no line numbers.
So I built a small tool to fix that for myself: JSON Formatter & Validator.
What it does
Paste any JSON → instant pretty-print with syntax highlighting. If the JSON is broken, it shows exactly where the error is — key, line, position.
There's also a Minify button for when you need to go the other direction (pasting into config files, API calls, etc.).
That's it. No login. No email. No ads. No 3MB of JavaScript loading before you can use the thing.
Why another JSON formatter?
Because the good ones are buried behind signup walls or slow as hell. The fast ones are ugly and don't tell you where your JSON broke.
I wanted something that:
- Loads in under a second on mobile
- Actually highlights which token is malformed
- Doesn't phone home with my API responses
Try it
👉 billion-jsonformat.pages.dev
Works on mobile too — useful when you're debugging a webhook response on your phone and don't have a laptop nearby.
What's your go-to JSON debugging workflow? Curious if people still use jq for this or if there are better browser tools I'm missing.
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