Open a JSON file and read it as a tree you can expand and collapse, instead of one enormous line. Your file never leaves this page. Everything happens in your browser, and there is no upload endpoint to send it to — that is checked by a build gate that fails if any network code reaches a tool’s bundle.
How to do it
- Drop in a
.jsonfile, or paste the JSON. - Expand the branches you care about.
- Collapse the ones you do not.
Questions
What if the JSON is invalid?
You are told where. The position of the problem is far more useful than being told only that something is wrong, and a misplaced comma in a large file is otherwise a long search.
How large a file can it handle?
Files of a few tens of megabytes are fine on a desktop. Beyond that the tree gets slow, because every node is a real element on the page.
Is my data sent anywhere?
No. This matters more here than on most pages — API responses and configuration files are exactly the kind of thing that carries a key or a token, and none of it leaves your browser.
Does it handle JSON Lines?
Not on this page. It expects one JSON document.