diff --git a/internal/services/smtp/service.go b/internal/services/smtp/service.go
index cff2f67b..d1415312 100644
--- a/internal/services/smtp/service.go
+++ b/internal/services/smtp/service.go
@@ -31,6 +31,7 @@ import (
 	"github.com/ProtonMail/proton-bridge/v3/internal/services/sendrecorder"
 	"github.com/ProtonMail/proton-bridge/v3/internal/services/userevents"
 	"github.com/ProtonMail/proton-bridge/v3/internal/services/useridentity"
+	"github.com/ProtonMail/proton-bridge/v3/internal/usertypes"
 	"github.com/ProtonMail/proton-bridge/v3/pkg/cpc"
 	"github.com/sirupsen/logrus"
 )
@@ -41,13 +42,6 @@ type Telemetry interface {
 	ReportSMTPAuthFailed(username string)
 }
 
-type AddressMode int
-
-const (
-	AddressModeCombined AddressMode = iota
-	AddressModeSplit
-)
-
 type Service struct {
 	userID       string
 	panicHandler async.PanicHandler
@@ -67,7 +61,7 @@ type Service struct {
 	addressSubscriber *userevents.AddressChanneledSubscriber
 	userSubscriber    *userevents.UserChanneledSubscriber
 
-	addressMode AddressMode
+	addressMode usertypes.AddressMode
 }
 
 func NewService(
@@ -80,7 +74,7 @@ func NewService(
 	keyPassProvider useridentity.KeyPassProvider,
 	telemetry Telemetry,
 	eventService userevents.Subscribable,
-	mode AddressMode,
+	mode usertypes.AddressMode,
 	identityState *useridentity.State,
 ) *Service {
 	subscriberName := fmt.Sprintf("smpt-%v", userID)
@@ -122,7 +116,7 @@ func (s *Service) SendMail(ctx context.Context, authID string, from string, to [
 	return err
 }
 
-func (s *Service) SetAddressMode(ctx context.Context, mode AddressMode) error {
+func (s *Service) SetAddressMode(ctx context.Context, mode usertypes.AddressMode) error {
 	_, err := s.cpc.Send(ctx, &setAddressModeReq{mode: mode})
 
 	return err
@@ -248,7 +242,7 @@ func (s *Service) sendMail(ctx context.Context, req *sendMailReq) error {
 }
 
 type setAddressModeReq struct {
-	mode AddressMode
+	mode usertypes.AddressMode
 }
 
 type checkAuthReq struct {
diff --git a/internal/services/smtp/smtp.go b/internal/services/smtp/smtp.go
index a59f7c10..8a19c04e 100644
--- a/internal/services/smtp/smtp.go
+++ b/internal/services/smtp/smtp.go
@@ -160,7 +160,7 @@ func (s *Service) smtpSendMail(ctx context.Context, authID string, from string,
 func (s *Service) sendWithKey(
 	ctx context.Context,
 	authAddrID string,
-	addrMode AddressMode,
+	addrMode usertypes.AddressMode,
 	settings proton.MailSettings,
 	userKR, addrKR *crypto.KeyRing,
 	emails []string,
@@ -241,7 +241,7 @@ func getParentID(
 	ctx context.Context,
 	client *proton.Client,
 	authAddrID string,
-	addrMode AddressMode,
+	addrMode usertypes.AddressMode,
 	references []string,
 ) (string, error) {
 	var (
@@ -263,7 +263,7 @@ func getParentID(
 	for _, internal := range internal {
 		var addrID string
 
-		if addrMode == AddressModeSplit {
+		if addrMode == usertypes.AddressModeSplit {
 			addrID = authAddrID
 		}
 
@@ -291,7 +291,7 @@ func getParentID(
 	if parentID == "" && len(external) > 0 {
 		var addrID string
 
-		if addrMode == AddressModeSplit {
+		if addrMode == usertypes.AddressModeSplit {
 			addrID = authAddrID
 		}
 
diff --git a/internal/user/user.go b/internal/user/user.go
index 2fdbb86a..ff517bdb 100644
--- a/internal/user/user.go
+++ b/internal/user/user.go
@@ -224,7 +224,7 @@ func New(
 		encVault,
 		user,
 		eventService,
-		vaultToSMTPAddressMode(encVault.AddressMode()),
+		usertypes.VaultToAddressMode(encVault.AddressMode()),
 		identityState.Clone(),
 	)
 
@@ -402,7 +402,7 @@ func (user *User) SetAddressMode(ctx context.Context, mode vault.AddressMode) er
 			return fmt.Errorf("failed to set address mode: %w", err)
 		}
 
-		if err := user.smtpService.SetAddressMode(ctx, vaultToSMTPAddressMode(mode)); err != nil {
+		if err := user.smtpService.SetAddressMode(ctx, usertypes.VaultToAddressMode(mode)); err != nil {
 			return fmt.Errorf("failed to set smtp address mode: %w", err)
 		}
 
@@ -917,15 +917,3 @@ func sleepCtx(ctx context.Context, d time.Duration) {
 	case <-time.After(d):
 	}
 }
-
-func vaultToSMTPAddressMode(mode vault.AddressMode) smtp.AddressMode {
-	var smtpAddressMode smtp.AddressMode
-
-	if mode == vault.SplitMode {
-		smtpAddressMode = smtp.AddressModeSplit
-	} else {
-		smtpAddressMode = smtp.AddressModeCombined
-	}
-
-	return smtpAddressMode
-}
diff --git a/internal/usertypes/addressmode.go b/internal/usertypes/addressmode.go
new file mode 100644
index 00000000..9c969f41
--- /dev/null
+++ b/internal/usertypes/addressmode.go
@@ -0,0 +1,47 @@
+// Copyright (c) 2023 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package usertypes
+
+import "github.com/ProtonMail/proton-bridge/v3/internal/vault"
+
+type AddressMode int
+
+const (
+	AddressModeCombined AddressMode = iota
+	AddressModeSplit
+)
+
+func VaultToAddressMode(mode vault.AddressMode) AddressMode {
+	var smtpAddressMode AddressMode
+
+	if mode == vault.SplitMode {
+		smtpAddressMode = AddressModeSplit
+	} else {
+		smtpAddressMode = AddressModeCombined
+	}
+
+	return smtpAddressMode
+}
+
+func AddressModeToVault(mode AddressMode) vault.AddressMode {
+	if mode == AddressModeCombined {
+		return vault.CombinedMode
+	}
+
+	return vault.SplitMode
+}