JSON Viewer Online
Paste a JSON document and read it as a tree instead of a wall of text. Everything happens inside your browser tab - the document is never uploaded, so it is safe to paste an API response that contains tokens or customer data.
What you can do with it
A JSON viewer earns its place when a document is too big to read directly. This one is built around that case rather than around a pretty demo.
- Collapse and expand any part of the document, so you can see structure before detail.
- Search keys and values at once, with the matched text highlighted where it appears.
- Step through matches with Enter, the way a browser find bar works.
- Select any value and get the code to reach it, in the language you are writing.
- Switch to a raw view for the formatted text, with line numbers.
Large files
Most online JSON viewers slow to a crawl somewhere around a megabyte, because they create a DOM element for every node in the document. This one draws only the rows currently on screen, so a document with a hundred thousand nodes scrolls at the same speed as one with ten.
Parsing a 9 MB document takes about 20 milliseconds. The expensive work - converting Python syntax - runs on a background thread so the interface never freezes. Past roughly 25 million characters the tool stops and asks before parsing, because a document that size can exhaust the memory a browser tab is allowed.
Privacy
The application makes no network requests at all. Not for parsing, not for analytics of your document, not for anything. You can confirm it by opening your browser devtools, switching to the Network tab, and pasting a document: nothing leaves.
That matters for a JSON viewer more than for most tools, because the documents people paste are usually API responses, and API responses usually contain credentials.
Questions
- Is this JSON viewer free?
- Yes, and there is no account to create. Open it and paste.
- Does my JSON get uploaded to a server?
- No. The tool makes no network requests. Your document is parsed and displayed entirely inside your browser tab.
- How large a JSON file can it open?
- Documents of several megabytes with hundreds of thousands of nodes stay responsive, because only the visible rows are rendered. Very large documents wait for your confirmation before parsing so that a big paste cannot freeze the tab by accident.
- Can it open a .json file from my computer?
- Yes. Drag the file onto the input area or use the Upload button. The file is read locally by your browser and is not transmitted anywhere.