zitadel/apps/login/readme.md

ZITADEL Login UI

This is going to be our next UI for the hosted login. It's based on Next.js 13 and its introduced app/ directory.

Flow Diagram

Back navigation or retrys are not displayed. The flows for reauthentication after registering Passkeys, OTP or U2F methods are not displayed either as these will be omitted in future UX.

    flowchart TD
    A[Start] --> register
    A[Start] --> accounts
    A[Start] --> loginname
    loginname -- signInWithIDP --> idp-success
    loginname -- signInWithIDP --> idp-failure
    idp-success --> B[signedin]
    loginname --> password
    loginname -- hasPasskey --> passkey
    loginname -- allowRegister --> register
    passkey-add --passwordAllowed --> password
    passkey -- hasPassword --> password
    passkey --> B[signedin]
    password -- hasMFA --> mfa
    password -- allowPasskeys --> passkey-add
    mfa --> otp
    otp --> B[signedin]
    mfa--> u2f
    u2f -->B[signedin]
    register --> passkey-add
    register --> password-set
    password-set --> B[signedin]
    passkey-add --> B[signedin]
    password --> B[signedin]
    password-- forceMFA -->mfaset
    mfaset --> u2fset
    mfaset --> otpset
    u2fset --> B[signedin]
    otpset --> B[signedin]
    accounts--> loginname
    password -- not verified yet -->verify
    register-- withpassword -->verify
    passkey-- notVerified --> verify
    verify --> B[signedin]

/loginname

This page shows a loginname field and Identity Providers to login or register. If loginSettings(org?).allowRegister is true, if will also show a link to jump to /register

Requests to the APIs made:

• getLoginSettings(org?)
• getLegalAndSupportSettings(org?)
• getIdentityProviders(org?)
• getBrandingSettings(org?)
• getActiveIdentityProviders(org?)
• startIdentityProviderFlow
• listUsers(org?)
• listAuthenticationMethodTypes
• getOrgsByDomain

After a loginname is entered, a listUsers request is made using the loginName query to identify already registered users.

USER FOUND: If only one user is found, we query listAuthenticationMethodTypes to identify future steps. If no authentication methods are found, we render an error stating: User has no available authentication methods. (exception see below.) Now if only one method is found, we continue with the corresponding step (/password, /passkey/login). If multiple methods are set, we prefer passkeys over any other method, so we redirect to /passkey, second option is IDP, and third is password. If password is the next step, we check loginSettings.passkeysType for PasskeysType.ALLOWED, and prompt the user to setup passkeys afterwards.

NO USER FOUND: If no user is found, we check whether registering is allowed using loginSettings.allowRegister. If loginSettings?.allowUsernamePassword is not allowed we continue to check for available IDPs. If a single IDP is available, we directly redirect the user to signup.

If no single IDP is set, we check for loginSettings.allowUsernamePassword and if no organization is set as context, we check whether we can discover a organization from the loginname of the user (using: getOrgsByDomain). Then if an organization is found, we check whether domainDiscovery is allowed on it and redirect the user to /register page including the discovered domain or without.

If no previous condition is met we throw an error stating the user was not found.

EXCEPTIONS: If the outcome after this order produces a no authentication methods found, or user not found, we check whether loginSettings?.ignoreUnknownUsernames is set to true as in this case we redirect to the /password page regardless (to not leak information about a registered user).

NOTE: We ignore loginSettings.allowExternalIdp as the information whether IDPs are available comes as response from getActiveIdentityProviders(org?).