Signing in
You sign in with your email address, a verified phone number or your slug. The hub works out which one you typed. You can also sign in with GitHub, Google, Apple, GitLab or Bitbucket, where the hub has each of them switched on, and a second factor, whether a passkey or a code from an authenticator app, is managed from the security section of your account. An email address that already belongs to another account is refused. That refusal is what stops one account from taking over another.
Behind the page, the hub runs its own sign-in server, Ory Hydra, which is an OpenID Connect server run headless. Hydra issues the tokens, and the hub draws every login, consent and sign-up page and keeps every account itself. One engine serves two kinds of realm. In the platform realm, developers sign in to the hub and its sister sites. In a customer realm, of which there is one for each ecosystem, a product's users sign in to that product. Which realm a client belongs to is worked out from the ecosystem the client was registered with. A client never declares it.