Open a zip file
See what is inside a zip, preview images and text and extract one file or the whole archive into a folder.
Drop a .zip here to see and extract what is inside.
The archive is opened on this device. Nothing is uploaded.
Why the directory is read first
A zip ends with a table of contents listing every file, its compressed size and its real size. Reading only that is instant even for a large archive and it means nothing is decompressed until you ask for it. It also means the tool knows how big everything will be before committing memory to it, which is the defence against a zip bomb.
Extracting safely
Zip entry names are paths and a hostile archive can name an entry something like../../startup/run.bat to write outside the folder you chose. Extract all refuses any path that tries to climb out of the destination folder and says which entries it skipped.
Checking it came out intact
Every entry carries a CRC checksum written when the archive was made. Extraction recomputes it and compares, so a download that was cut short or an archive that was damaged in transit shows up as a named failure rather than as a file that’ll not open later.
Common questions
Is the zip uploaded to be opened?
No. The archive is read in this tab. Only the directory at the end of the file is read at first, so you see the contents immediately and an entry is decompressed only when you preview, download or extract it.
Can I extract everything at once?
In Chrome and Edge, yes: extract all asks for a folder and writes every file into it, subfolders included. Other browsers don’t let a web page write a folder, so there each file downloads individually from the list.
What is a zip bomb and does this protect against it?
A small archive built to expand to an enormous size and exhaust memory. Because the true size of every entry is listed in the directory, the tool checks it before decompressing anything and refuses extract all for an archive that would expand past two gigabytes or contains an entry compressed over a thousand to one.
Why can I not open a password protected zip?
Browsers have no built-in support for zip encryption and the older encryption scheme most zips use is weak enough that it shouldn’t be relied on anyway. Protected entries are marked in the list rather than failing silently.
What if the archive is damaged?
Each entry carries a checksum and every extraction is checked against it. A truncated download or a corrupted archive is reported by name for the entry that failed, instead of handing you a broken file that looks fine until you open it.
Guides
The other tools
All of them work the same way: the file is read in your browser and never uploaded.