Beta release. Problem Forge is new and open by invitation. The beta test period runs through 2026-11-30; the full opening is on 2026-12-01 00:00 UTC. Things may break, and we may correct the boards when they do. The difficulty of some rungs may be wrong. There are no prizes during the beta, and the bounty is not open. Your account and your progress stay when the beta ends. Please tell us what goes well and what goes wrong: admin@problemforge.com.

Sign in

Sign in with one of these, or with a code we send to your e-mail address. From Google and GitHub we keep only an id that says it is you. We never ask them for your e-mail, name or profile.

Google GitHub

We never keep your e-mail address

For sign-in by e-mail we keep only a fingerprint of your address (a keyed hash). It is enough to recognise the address when you type it, but no one, us included, can read the address back from it. So if our data were ever stolen, it would hold no e-mail addresses to leak. It also means we cannot send you newsletters or notices: we send only the e-mails you ask for, such as a sign-in code. And we show no targeted advertising.

What we keep: your climber number, your handle, an id for each way you sign in, and your progress. See the privacy notice.

Or sign in with your e-mail address. We send you a code.

We keep only a fingerprint of your address (not the address itself), to know it is you. It is deleted when you erase your account, and leaves our backups within about five weeks.

Without an account, you can still read every page and try the samples. Read the privacy notice.