Large JSON Viewer
Open JSON files up to 500MB right in your browser, without the tab freezing. Nothing is uploaded — the file stays on your computer.
Why regular JSON viewers choke on big files
Most of them load the entire file at once and try to draw every line on screen. That is fine for a few megabytes. At a few hundred, the tab freezes. This one works differently:
- • It reads the file in small pieces instead of all at once
- • It only draws the rows you can actually see, so a file with 200,000 of them still scrolls smoothly
- • Nested items are opened only when you click to open them
- • Search shows a progress bar, so you know it is working
- • We never see your data — the file never leaves your browser
Typical use cases
- • A big API export or database dump saved as JSON
- • A long configuration or infrastructure-as-code file
- • An analytics or logging payload you want to check before using it
- • A machine learning dataset or model output file
Line-delimited instead?
If your file has one JSON object on every line, use the NDJSON Viewer — it goes line by line, which suits logs and exports better. For everyday, smaller files, the plain JSON Viewer has the same tree.
FAQ
What's the actual size limit?
Files up to about 500MB open reliably. Past that it depends on how much memory your device has, because the file is handled by your browser rather than by a server.
Does the file get uploaded to a server?
No — We never see your data. The file is read on your own computer. Nothing is sent anywhere unless you choose to load it from a URL.
Will my browser tab freeze while it loads?
No. The file is read in pieces and only the visible rows are drawn, so the page keeps responding while a large file is still loading.