Bug Bounty

PythonAnywhere offers a bounty for responsibly disclosed bugs. We determine the payout depending on the severity and impact of the submitted bug. We only pay out on the first report of a particular issue, so it's best if you contact us first to see whether we're already working on something.


Please only report vulnerabilities for:

  • www.pythonanywhere.com and eu.pythonanywhere.com -- please note that these are two instances of the same site, so a bug reported against one of them counts as a bug against the other. We will not pay a bounty for a bug on eu.pythonanywhere.com if a bounty has already been paid for the same bug on www.pythonanywhere.com, and vice versa.

  • blog.pythonanywhere.com

  • help.pythonanywhere.com

  • integration.pythonanywhere.com

As we are a web-hosting company, our users may have created websites that have bugs using our platform. These might be hosted at URLs like username.pythonanywhere.com. Do not report bugs in those sites to us; if you can find contact details on the sites, you are welcome to contact their owners directly.

Bug classes we're not really interested in

  • "I can run code on your servers" - Yup. That's our business.

  • Self XSS -- If you can execute XSS-style attacks against your own account by uploading a file and then loading it in the browser, that's not particularly interesting to us.

  • Auto-pwnage -- "If I run this code it does something bad to my account/files/web apps"

  • Attacks that assume that accounts need to have unique email addresses. We allow multiple accounts to have the same email address.

  • Attacks that assume a users' login session has already been compromised. If an attacker has access to a logged-in session by a user, we pretty much consider that "game over" already, since the attacker already has full access to all the users' files and data etc. So the fact that the attacker may be able to, eg, brute force an email reset as well, isn't something we consider a serious additional security risk.

Bug classes we're interested in

  • General XSS, CSRF etc. -- Can you get a user that is logged in to PythonAnywhere to do something malicious to their own account by e.g. having them follow a link?

  • Cross-user exploits -- Can you do something bad to another user on PythonAnywhere from your account? Unless you're a teacher doing something malicious to your students - there's an explicit trust relationship, there.

  • Information leakage -- Can you learn something private (see their files, access account information) about another user/account registered on PythonAnywhere?

Bug classes we're very interested in

  • Session/cookie hijacking.

  • OS-level privilege escalation in consoles, web apps, Jupyter notebooks and scheduled/always-on tasks.

  • Sandbox escape in consoles, web apps, Jupyter notebooks and scheduled/always-on tasks.


Send reports to support@pythonanywhere.com.

All reports must be accompanied by a proof of concept that we can reproduce.


  • We only pay out bug bounties to the first report (not subsequent reports of the same bug).
  • We pay US$50-100 for bug reports that we deem low severity, or which need a very complicated and unlikely sequence of events to be exploited.
  • We pay US$100-500 for bugs that we deem more serious, and are directly exploitable.
  • We may pay upwards of US$1000 for bugs that we deem very high severity.
  • Payouts are made by PayPal, and you are responsible for any fees you incur receiving the payout.

Not a bugs - common source of security researchers confusion

  • Users can create multiple accounts with one email.