Projects FAQ

This FAQ guide answers questions about Projects.

Upgrades/quotas, billing, and pricing related questions covered in Billing/Upgrades FAQ.

Can I work with Git – including GitHub, Bitbucket, GitLab, etc.?

Git and various other source control tools are installed and ready to use via the Linux Terminal. But, in order to also interoperate with sites hosting Git repositories, you have to purchase a plan giving you “internet upgrades” and then applying this upgrade to your project.

More information: CoCalc Git Howto

How can I download my files?

  • You can download each file individually via the “Files” interface. Select the file and click the “Download” button.

  • It is also possible to create an archive for a directory or all files. For that, create a “Terminal”-file and issue one of these commands:

    • ZIP archive (Windows): zip -r9 "[filename].zip" [directory-name...]

    • Tarball (Unix-like): tar cjvf "[filename].tar.bz2" [directory-name...]

    (Replace [filename] with the actual filename and [directory-name] by one or more filenames or directory names.) Afterwards, download the archive as explained above.

Are my files backed up?

Yes! See Backups for details.

Can I close my web-browser at any time?


When you close your web-browser, all your processes and running sessions continue running. You can start a computation, shut down your computer, go somewhere else, sign in on another computer, and continue working where you left off.

The only reasons why a project or process stops are that it hits its idle timeout, was killed after using too much memory, crashed due to an exception, or the server had to reboot.

What’s the fingerprint of the SSH gateway’s host key?

How can I make sure to connect to CoCalc? As of September 2019, the SSH host key’s fingerprint is:

2048 MD5:b1:92:cc:67:ee:b8:ff:65:48:93:e6:f1:72:93:59:b0 cocalc@kucalc-k3-ctl (RSA)

You can see it when you try to connect via:

ssh -v -o FingerprintHash=md5

Somewhere in the output it says:

debug1: Server host key: ssh-rsa MD5:b1:92:cc:67:ee:b8:ff:65:48:93:e6:f1:72:93:59:b0

Note: this key could have changed due to technical reasons. Please contact us at if you suspect a discrepancy.