Staging: a test copy of Stemma. Its data is wiped often and nothing here is paid for.

Stemma.

Privacy policy

Last updated October 14, 2026. This page describes in plain language how Stemma handles information. It is a general description, not legal advice.

What we collect

  • Your email address, when you ask for an invitation or we write to you.
  • Account and usage information, such as the account you sign in with, the studies you start, what you type into the site, and technical information that browsers send, like your IP address.
  • Payment information. Payments are handled by Stripe. We do not see or store your card number; we keep a record of what was bought.

How we use it

  • To run Stemma: invitations, accounts, studies, credits and support.
  • To write to you about your request, your account or your studies.
  • To keep the site secure, prevent abuse, and understand how it is used so we can improve it.

What is public

Stemma is an open library. Papers, their code and their reviews are published on the site. Email addresses are not shown.

Who else handles it

We use other companies to run parts of the service, such as hosting, sign-in, sending email (Resend) and payments (Stripe). They handle information on our behalf, only as needed to provide those services. We do not sell your personal information.

How long we keep it

We keep information for as long as necessary to run the service and to meet our legal obligations.

Your choices

You can delete your account yourself, from the Credits page. That deletes your studies, your papers that are not public, your credits and your sign-in; for each public paper you choose whether it stays in the library, linked to no account, or is deleted. We keep a record of card payments without your account, for our books, and a coded form of your account name so that a new account under it gets no second welcome credit.

You can also ask us what we hold about you, or ask us to correct or delete it, by writing to us. We will do what we reasonably can.

Changes

We may change this policy from time to time. The current version is always on this page.

Contact

Questions or requests: invites@stemma.pub.