diff --git a/connector/connector.go b/connector/connector.go
index 2cfc7191..fc238bc5 100644
--- a/connector/connector.go
+++ b/connector/connector.go
@@ -9,6 +9,9 @@ import (
 
 // Connector connects the gluon server to a remote mail store.
 type Connector interface {
+	// Authorize returns whether the given username/password combination are valid for this connector.
+	Authorize(username, password string) bool
+
 	// GetUpdates returns a stream of updates that the gluon server should apply.
 	GetUpdates() <-chan imap.Update
 
diff --git a/connector/dummy.go b/connector/dummy.go
index aa3dc4ef..14da24e2 100644
--- a/connector/dummy.go
+++ b/connector/dummy.go
@@ -21,6 +21,9 @@ type Dummy struct {
 	// state holds the fake connector state.
 	state *dummyState
 
+	// username and password are the credentials for this connector.
+	username, password string
+
 	// These hold the default flags/attributes given to mailboxes.
 	flags, permFlags, attrs imap.FlagSet
 
@@ -38,9 +41,11 @@ type Dummy struct {
 	queueLock sync.Mutex
 }
 
-func NewDummy(period time.Duration, flags, permFlags, attrs imap.FlagSet) *Dummy {
+func NewDummy(username, password string, period time.Duration, flags, permFlags, attrs imap.FlagSet) *Dummy {
 	conn := &Dummy{
 		state:     newDummyState(flags, permFlags, attrs),
+		username:  username,
+		password:  password,
 		flags:     flags,
 		permFlags: permFlags,
 		attrs:     attrs,
@@ -62,6 +67,10 @@ func NewDummy(period time.Duration, flags, permFlags, attrs imap.FlagSet) *Dummy
 	return conn
 }
 
+func (conn *Dummy) Authorize(username, password string) bool {
+	return username == conn.username && password == conn.password
+}
+
 func (conn *Dummy) GetUpdates() <-chan imap.Update {
 	return conn.updateCh
 }
diff --git a/connector/dummy_test.go b/connector/dummy_test.go
index 20f3b197..453e610d 100644
--- a/connector/dummy_test.go
+++ b/connector/dummy_test.go
@@ -18,6 +18,8 @@ var (
 
 func TestDummyConnector_ValidateCreate(t *testing.T) {
 	conn := NewDummy(
+		"username",
+		"password",
 		defaultPeriod,
 		defaultFlags,
 		defaultPermanentFlags,
@@ -67,6 +69,8 @@ func TestDummyConnector_ValidateCreate(t *testing.T) {
 
 func TestDummyConnector_ValidateUpdate(t *testing.T) {
 	conn := NewDummy(
+		"username",
+		"password",
 		defaultPeriod,
 		defaultFlags,
 		defaultPermanentFlags,
@@ -97,6 +101,8 @@ func TestDummyConnector_ValidateUpdate(t *testing.T) {
 
 func TestDummyConnector_ValidateDelete(t *testing.T) {
 	conn := NewDummy(
+		"username",
+		"password",
 		defaultPeriod,
 		defaultFlags,
 		defaultPermanentFlags,
diff --git a/demo/demo.go b/demo/demo.go
index bb1931bc..c91c95b0 100644
--- a/demo/demo.go
+++ b/demo/demo.go
@@ -26,6 +26,8 @@ func main() {
 	server := gluon.New(filepath.Join(dir, "server"))
 
 	connector := connector.NewDummy(
+		"user@example.com",
+		"password",
 		time.Second,
 		imap.NewFlagSet(),
 		imap.NewFlagSet(),
@@ -37,18 +39,18 @@ func main() {
 		logrus.WithError(err).Fatal("Failed to create store")
 	}
 
-	if err := server.AddUser(
-		"userID",
-		"username",
-		"password",
+	userID, err := server.AddUser(
 		connector,
 		store,
 		dialect.SQLite,
 		fmt.Sprintf("file:%v?cache=shared&_fk=1", filepath.Join(dir, fmt.Sprintf("%v.db", "userID"))),
-	); err != nil {
+	)
+	if err != nil {
 		logrus.WithError(err).Fatal("Failed to add user")
 	}
 
+	logrus.WithField("userID", userID).Info("User added to server")
+
 	listener, err := net.Listen("tcp", ":1143")
 	if err != nil {
 		logrus.WithError(err).Fatal("Failed to listen")
diff --git a/events/user.go b/events/user.go
index 1c8d82ae..93431711 100644
--- a/events/user.go
+++ b/events/user.go
@@ -1,8 +1,7 @@
 package events
 
 type EventUserAdded struct {
-	UserID   string
-	Username string
+	UserID string
 }
 
 func (EventUserAdded) _isEvent() {}
diff --git a/internal/backend/backend.go b/internal/backend/backend.go
index c12a020b..4c08f130 100644
--- a/internal/backend/backend.go
+++ b/internal/backend/backend.go
@@ -9,6 +9,7 @@ import (
 	"github.com/ProtonMail/gluon/internal/backend/ent"
 	"github.com/ProtonMail/gluon/internal/remote"
 	"github.com/ProtonMail/gluon/store"
+	"github.com/google/uuid"
 	"github.com/sirupsen/logrus"
 )
 
@@ -36,23 +37,25 @@ func (b *Backend) SetDelimiter(delim string) {
 	b.delim = delim
 }
 
-func (b *Backend) AddUser(userID, username, password string, conn connector.Connector, store store.Store, client *ent.Client) error {
+func (b *Backend) AddUser(conn connector.Connector, store store.Store, client *ent.Client) (string, error) {
 	b.usersLock.Lock()
 	defer b.usersLock.Unlock()
 
-	remote, err := b.remote.AddUser(userID, username, password, conn)
+	userID := uuid.NewString()
+
+	remote, err := b.remote.AddUser(userID, conn)
 	if err != nil {
-		return err
+		return "", err
 	}
 
 	user, err := newUser(userID, client, remote, store, b.delim)
 	if err != nil {
-		return err
+		return "", err
 	}
 
 	b.users[userID] = user
 
-	return nil
+	return userID, nil
 }
 
 func (b *Backend) GetState(username, password string) (*State, error) {
diff --git a/internal/remote/manager.go b/internal/remote/manager.go
index 28f33ef4..3215d5eb 100644
--- a/internal/remote/manager.go
+++ b/internal/remote/manager.go
@@ -32,7 +32,7 @@ func New(dir string) *Manager {
 
 // AddUser adds the remote user with the given (IMAP) credentials to the remote manager.
 // The user interacts with the remote via the given connector.
-func (m *Manager) AddUser(userID, username, password string, conn connector.Connector) (*User, error) {
+func (m *Manager) AddUser(userID string, conn connector.Connector) (*User, error) {
 	m.usersLock.Lock()
 	defer m.usersLock.Unlock()
 
@@ -41,7 +41,7 @@ func (m *Manager) AddUser(userID, username, password string, conn connector.Conn
 		return nil, err
 	}
 
-	user, err := newUser(userID, username, password, path, conn)
+	user, err := newUser(userID, path, conn)
 	if err != nil {
 		return nil, err
 	}
@@ -57,7 +57,7 @@ func (m *Manager) GetUserID(username, password string) (string, error) {
 	defer m.usersLock.Unlock()
 
 	for _, user := range m.users {
-		if user.username == username && user.password == password {
+		if user.conn.Authorize(username, password) {
 			return user.userID, nil
 		}
 	}
diff --git a/internal/remote/user.go b/internal/remote/user.go
index dbcec03b..8157bf4c 100644
--- a/internal/remote/user.go
+++ b/internal/remote/user.go
@@ -13,9 +13,7 @@ import (
 
 // User performs operations against a remote server using a connector.
 type User struct {
-	userID   string
-	username string
-	password string
+	userID string
 
 	// path is the path at which the operation queue will be saved to disk.
 	path string
@@ -40,11 +38,9 @@ type User struct {
 // newUser constructs a new user with the given (IMAP) credentials.
 // It serializes its operation queue to a file at the given filepath,
 // and performs remote operations using the given connector.
-func newUser(userID, username, password, path string, conn connector.Connector) (*User, error) {
+func newUser(userID, path string, conn connector.Connector) (*User, error) {
 	user := &User{
 		userID:    userID,
-		username:  username,
-		password:  password,
 		path:      path,
 		conn:      conn,
 		updatesCh: make(chan imap.Update),
diff --git a/server.go b/server.go
index ecc82128..ac20e98e 100644
--- a/server.go
+++ b/server.go
@@ -65,22 +65,22 @@ func New(dir string, withOpt ...Option) *Server {
 }
 
 // AddUser makes a user available to the mailserver.
-func (s *Server) AddUser(userID, username, password string, conn connector.Connector, store store.Store, driver, source string) error {
+func (s *Server) AddUser(conn connector.Connector, store store.Store, driver, source string) (string, error) {
 	client, err := ent.Open(driver, source)
 	if err != nil {
-		return err
+		return "", err
 	}
 
-	if err := s.backend.AddUser(userID, username, password, conn, store, client); err != nil {
-		return err
+	userID, err := s.backend.AddUser(conn, store, client)
+	if err != nil {
+		return "", err
 	}
 
 	s.publish(events.EventUserAdded{
-		UserID:   userID,
-		Username: username,
+		UserID: userID,
 	})
 
-	return nil
+	return userID, nil
 }
 
 // AddWatcher adds a new watcher.
diff --git a/tests/server_test.go b/tests/server_test.go
index 585d2e2b..9ba921f4 100644
--- a/tests/server_test.go
+++ b/tests/server_test.go
@@ -13,7 +13,6 @@ import (
 	"github.com/ProtonMail/gluon"
 	"github.com/ProtonMail/gluon/connector"
 	"github.com/ProtonMail/gluon/imap"
-	"github.com/ProtonMail/gluon/internal/utils"
 	"github.com/ProtonMail/gluon/store"
 	"github.com/emersion/go-imap/client"
 	"github.com/google/uuid"
@@ -50,24 +49,25 @@ func runServer(tb testing.TB, credentials map[string]string, delim string, tests
 	userIDs := make(map[string]string)
 	conns := make(map[string]Connector)
 
-	for user, pass := range credentials {
-		userID := utils.NewRandomUserID()
-
+	for username, password := range credentials {
 		conn := connector.NewDummy(
+			username,
+			password,
 			defaultPeriod,
 			defaultFlags,
 			defaultPermanentFlags,
 			defaultAttributes,
 		)
 
-		store, err := store.NewOnDiskStore(tb.TempDir(), []byte("passphrase"))
+		store, err := store.NewOnDiskStore(tb.TempDir(), []byte(password))
 		require.NoError(tb, err)
 
-		require.NoError(tb, server.AddUser(userID, user, pass, conn, store, dialect.SQLite, getEntPath(tb.TempDir(), userID)))
+		userID, err := server.AddUser(conn, store, dialect.SQLite, getEntPath(tb.TempDir()))
+		require.NoError(tb, err)
 
 		require.NoError(tb, conn.Sync(ctx))
 
-		userIDs[user] = userID
+		userIDs[username] = userID
 		conns[userID] = conn
 	}
 
@@ -125,6 +125,6 @@ func withData(s *testSession, username string, tests func(string, string)) {
 	tests(mbox, mboxID)
 }
 
-func getEntPath(dir, userID string) string {
-	return fmt.Sprintf("file:%v?cache=shared&_fk=1", filepath.Join(dir, fmt.Sprintf("%v.db", userID)))
+func getEntPath(dir string) string {
+	return fmt.Sprintf("file:%v?cache=shared&_fk=1", filepath.Join(dir, fmt.Sprintf("%v.db", uuid.NewString())))
 }