Look inside before you commit anything to disk

A ZIP is a container of individually compressed files plus a directory listing recording each one's name, size and path. That index sits separately from the compressed contents, which is why the whole listing can be shown instantly without decompressing a byte.

And that is the argument for opening one here rather than in your operating system. Double-clicking an archive writes every file to disk in a single action, and you learn what was inside afterwards. Reading the listing first inverts that: see the names, the count and the sizes, then take only what you actually want.

Three ordinary situations where that matters — an archive far bigger than the download suggested, one file wanted out of two hundred, and working on a machine where you would rather not scatter unfamiliar files through your downloads folder.

What you get

• Every file and folder with its full path
• Compressed and uncompressed size per file, and the overall compression ratio
• A download button per file, or download everything
• A filter box for finding something in a large archive

One practical note on downloads: the listing shows full paths, but files arrive individually in your normal downloads folder rather than recreating the folder tree — a browser cannot build directories on your disk. For an archive whose structure matters, extract it with a desktop tool instead.

Size limit, and the reason for it

Archives up to 200 MB work. Above that it fails, and the reason is worth stating plainly rather than presenting as a policy: extraction happens in the browser, which means the file is held in memory. A desktop archive tool streams from disk and has no equivalent limit, so it is the right tool for anything large.

Encrypted archives

Password-protected archives cannot be opened here — extraction will simply fail. Use your operating system or a desktop archive program, which support encrypted entries.

A word on unfamiliar archives

An archive from an unknown source is unknown content, and the names inside it were chosen by whoever built it. An extension can be misleading, and a file name can be constructed to look innocuous.

The ordinary precautions are enough: read the listing before extracting anything, be wary of executables such as .exe, .msi, .bat and .cmd, and treat an unexpected archive arriving by email with suspicion regardless of who it appears to be from. Being able to see the contents without extracting them is exactly the point of reading the index first.

Where the files go

Nowhere but your own machine. The archive is read in the browser and never uploaded, and closing the tab discards everything.

That matters more here than on most tools, because archives are what people use to move documents in bulk — invoices, scans, exports — and those are precisely the files you would not want going to someone else's server to be unpacked.

Spreadsheets turn up inside archives constantly. Once you have one out, the XLSX to CSV converter will turn it into something a script or a database import can read.