Open a ZIP file online, in your browser

A .zip archive that arrives by email or comes from a portal opens directly in C-A-R-T-A, in the browser of your computer, phone or tablet. There is no archive program to install and the file is not uploaded to any server: the archive is read and unpacked on your device.

Open C-A-R-T-A

How to open it

Open C-A-R-T-A and press "Open" (or Ctrl+O), or drag the .zip file onto the page. With C-A-R-T-A installed as an app, you can also use "Open with…" from your system.
The list of files inside appears, with the name, the folder they come from and the size.
Tap a file: it opens in a new tab, as if you had chosen it yourself. "Back" takes you to the archive list, where you can open another one.

Each file opens with the features of its format: a PDF with all the PDF features, a signed .p7m file with signature checking, an XML e-invoice in readable form, an image or a TIFF as described on the formats page.

What does not open, and why

C-A-R-T-A does not open everything an archive may hold. When a file cannot be opened, it stays in the list with the reason written next to it, and its button is disabled.

Password-protected files. Encrypted archives are recognised but not opened: for those you need an archive program.
"Zip bombs". A file that swells suspiciously when unpacked (an absurd compression ratio) is flagged and not extracted. During extraction too, as soon as a file goes beyond its declared size, C-A-R-T-A stops: an archive built to fill up the memory does not fill it.
Files that are too large. A single file larger than 300 MB once unpacked does not open: it would not fit in a phone's memory.
Unusual compression methods. Uncompressed files and files compressed the standard way (deflate) open, which covers almost every .zip archive in circulation. Other methods are shown as not recognised.
Names with unusual paths. A name that tries to "step out" of the archive (with "../" or an absolute path) is flagged. It is not a risk, because C-A-R-T-A writes nothing to disk: it only shows it.

Your files stay on your device

The archive does not go to any server: listing and extraction happen in the browser. A document's text leaves your device only if, after opening it, you use an AI feature or the "On the server" OCR yourself. Details on the privacy page.

Which browsers

Unpacking needs a recent browser: Chrome and Edge, Safari from version 16.4 (iPhone and iPad included) and Firefox from version 113. On an older browser C-A-R-T-A says so with a message, instead of failing silently.

Quick questions

Can I create a .zip archive?

Yes, but from another feature: Several files at once processes a group of files and gives them back in a single .zip archive.

What if I have many loose files instead of an archive?

They open together even without an archive: choose more than one from "Open" or drag them all onto the page. Each one goes into its own tab, up to 8.

Does it work without internet?

Yes. After the first visit, C-A-R-T-A keeps the program on your device and unpacks archives without a network too.