feat: passwordless support

README.md

@@ -229,6 +229,10 @@ Let a logged-in user manage their own enrolled authentication methods — enroll
 
 Bind tokens to a key your server holds ([RFC 9449](https://www.rfc-editor.org/rfc/rfc9449)) so a stolen token alone cannot be replayed. DPoP is supported for Passkey sign-in (`signin_with_passkey`) and the authentication-methods/factors methods on `MyAccountClient`. For key generation and usage, see [examples/Passkeys.md](examples/Passkeys.md#3-dpop-bound-passkey-tokens-optional) and [examples/MyAccountAuthenticationMethods.md](examples/MyAccountAuthenticationMethods.md#dpop).
 
+### 10. Passwordless Authentication
+
+Sign users in with a one-time code sent by email or SMS, or with a magic link sent by email, via [Auth0 embedded passwordless login](https://auth0.com/docs/authenticate/passwordless/implement-login/embedded-login/relevant-api-endpoints). OTP verification and the magic-link callback each establish a server-side session like every other login path. For prerequisites, both flows, custom scopes/audiences, step-up MFA, and error handling, see [examples/Passwordless.md](examples/Passwordless.md).
+
 ## Feedback
 
 ### Contributing

examples/MFA.md

@@ -545,15 +545,16 @@ The SDK does not store your private key, so you must re-supply it on the `verify
 
 By default, `verify()` returns tokens without persisting them to the session store. However, you can automatically persist tokens by setting `persist=True`.
 
-> [!WARNING]
-> `persist=True` **updates an existing session** — it does not create one. On a passkey-first login (`signin_with_passkey` → `MfaRequiredError`) no session exists yet, so `persist=True` raises `MfaVerifyError("No existing session found to update with MFA tokens")` and discards the tokens `verify()` just obtained. On that path, use `persist=False` (the default) and store the returned tokens yourself — see [Passkeys.md → Completing MFA on a passkey login](Passkeys.md#completing-mfa-on-a-passkey-login-and-where-the-session-comes-from).
+> [!NOTE]
+> `persist=True` updates an existing session when one is present. For first login MFA flows where the SDK has not created a session yet, `ServerClient.mfa` can create the initial session from the final MFA token response when that response includes an ID token.
 
 ### Automatic Session Update
 
 When you set `persist=True`, the SDK will:
-1. Update the session's `access_token` for the specified audience
-2. Update the session's `id_token` if present
-3. Add the token to the `token_sets` array with expiration information
+1. Update an existing session, or create the initial session when the MFA flow completed a first login
+2. Persist the `access_token` for the specified audience
+3. Persist the `id_token` if present
+4. Add the token to the `token_sets` array with expiration information
 
 ```python
 verify_response = await server_client.mfa.verify(

references/docs-update.md

@@ -63,3 +63,4 @@ it from `README.md`'s section for the feature. Name the file after the flow, mat
 | CIBA | `examples/ClientInitiatedBackChannelLogin.md` |
 | MCD domain resolver | `examples/MultipleCustomDomains.md` |
 | Account linking / unlinking | `examples/UserLinking.md` |
+| Passwordless email/SMS OTP + magic link | `examples/Passwordless.md` |

src/auth0_server_python/auth_server/__init__.py

@@ -1,5 +1,6 @@
 from .mfa_client import MfaClient
 from .my_account_client import MyAccountClient
+from .passwordless_client import PasswordlessClient
 from .server_client import ServerClient
 
-__all__ = ["ServerClient", "MyAccountClient", "MfaClient"]
+__all__ = ["ServerClient", "MyAccountClient", "MfaClient", "PasswordlessClient"]

src/auth0_server_python/auth_server/mfa_client.py

@@ -5,7 +5,8 @@
 
 import json
 import time
-from typing import TYPE_CHECKING, Any, Callable, Optional, Union
+from collections.abc import Awaitable, Callable
+from typing import TYPE_CHECKING, Any, Optional, Union
 
 import httpx
 
@@ -28,6 +29,7 @@
 )
 from auth0_server_python.encryption.encrypt import decrypt, encrypt
 from auth0_server_python.error import (
+    ConfigurationError,
     DomainResolverError,
     MfaChallengeError,
     MfaEnrollmentError,
@@ -67,7 +69,11 @@ def __init__(
         state_store=None,
         state_identifier: str = "_a0_session",
         headers: Optional[dict[str, str]] = None,
-        apply_client_authentication: Optional[Callable] = None
+        session_establisher: Optional[
+            Callable[..., Awaitable[None]]
+        ] = None,
+        mfa_token_ttl: int = DEFAULT_MFA_TOKEN_TTL,
+        apply_client_authentication: Optional[Callable] = None,
     ):
         if callable(domain):
             self._domain = None
@@ -81,6 +87,10 @@ def __init__(
         self._state_store = state_store
         self._state_identifier = state_identifier
         self._headers = headers or {}
+        self._session_establisher = session_establisher
+        if mfa_token_ttl <= 0:
+            raise ConfigurationError("mfa_token_ttl must be a positive number of seconds")
+        self._mfa_token_ttl = mfa_token_ttl
         self._apply_client_authentication = apply_client_authentication
 
     def _get_http_client(self, **kwargs) -> httpx.AsyncClient:
@@ -146,7 +156,7 @@ def decrypt_mfa_token(self, encrypted_token: str) -> MfaTokenContext:
             raise MfaTokenInvalidError()
 
         elapsed = int(time.time()) - context.created_at
-        if elapsed > DEFAULT_MFA_TOKEN_TTL:
+        if elapsed > self._mfa_token_ttl:
             raise MfaTokenExpiredError()
 
         return context
@@ -638,6 +648,14 @@ async def _persist_mfa_tokens(
             )
 
             if not state_data:
+                if self._session_establisher:
+                    await self._session_establisher(
+                        verify_response=verify_response,
+                        audience=audience,
+                        scope=scope,
+                        store_options=store_options,
+                    )
+                    return
                 raise MfaVerifyError(
                     "No existing session found to update with MFA tokens"
                 )