How to json validator & formatter without breaking your data

A payload throws "Unexpected token" and nothing else. You scroll through 900 lines looking for a missing comma, and the browser console truncates the message right before the part that matters.

You see this most often in webhook payloads, API fixtures, config files copied from a chat message. Most online formatters pretty-print invalid JSON as far as they can parse it, which makes a broken file look almost fine.

Doing it in four steps

1. Paste the payload
2. Run the validator to get the exact line and column
3. Fix that position and re-run
4. Copy the formatted output

The whole thing runs locally in the browser tab: no upload, no account, no queue. When the page says "removed 37 lines", that number comes from the file you just pasted, not from a sample.

Because the parser reports the byte offset, a 900-line payload becomes a two-second fix instead of a scroll-and-squint session.

For the full picture — imports, feeds, variants, identifiers — see the pillar guide: Shopify product data management.

Try it on your own file

Open JSON Validator & Formatter and paste a sample. It is free, it does not store anything, and you do not need an account. If the file is sensitive, save the page locally and run it offline.

Questions people ask

Does it show where the error is?

Yes — it reports the line and column from the parser, not just "invalid JSON".

Can I minify instead?

Yes, there is a separate minify action on the same page.