diff --git a/config/config.go b/config/config.go
index f24526c..d1af7e8 100644
--- a/config/config.go
+++ b/config/config.go
@@ -16,6 +16,7 @@ const (
 	voucherTransfersPathPrefix = "/api/v1/transfers/last10"
 	voucherDataPathPrefix      = "/api/v1/token"
 	AliasPrefix                = "api/v1/alias"
+	SendSMSPrefix              = "api/v1/external/upsell"
 	AliasEnsPrefix             = "/api/v1/bypass"
 )
 
@@ -36,6 +37,7 @@ var (
 	VoucherTransfersURL string
 	VoucherDataURL      string
 	CheckAliasURL       string
+	SendSMSURL          string
 	AliasEnsURL         string
 )
 
@@ -73,6 +75,7 @@ func LoadConfig() error {
 	VoucherTransfersURL, _ = url.JoinPath(dataURLBase, voucherTransfersPathPrefix)
 	VoucherDataURL, _ = url.JoinPath(dataURLBase, voucherDataPathPrefix)
 	CheckAliasURL, _ = url.JoinPath(dataURLBase, AliasPrefix)
+	SendSMSURL, _ = url.JoinPath(dataURLBase, SendSMSPrefix)
 	AliasEnsURL, _ = url.JoinPath(aliasEnsURLBase, AliasEnsPrefix)
 	return nil
 }
diff --git a/models/send_sms_response.go b/models/send_sms_response.go
new file mode 100644
index 0000000..1f6a70f
--- /dev/null
+++ b/models/send_sms_response.go
@@ -0,0 +1,5 @@
+package models
+
+type SendSMSResponse struct {
+	Invitee string `json:"invitee"`
+}
diff --git a/remote/account_service.go b/remote/account_service.go
index 2c67b12..07e697e 100644
--- a/remote/account_service.go
+++ b/remote/account_service.go
@@ -17,4 +17,5 @@ type AccountService interface {
 	TokenTransfer(ctx context.Context, amount, from, to, tokenAddress string) (*models.TokenTransferResponse, error)
 	CheckAliasAddress(ctx context.Context, alias string) (*models.AliasAddress, error)
 	RequestAlias(ctx context.Context, hint string, publicKey string) (*models.RequestAliasResult, error)
+	SendUpsellSMS(ctx context.Context, inviterPhone, inviteePhone string) (*models.SendSMSResponse, error)
 }
diff --git a/remote/http/service.go b/remote/http/service.go
index 82a756e..7ddccde 100644
--- a/remote/http/service.go
+++ b/remote/http/service.go
@@ -313,6 +313,37 @@ func requestEnsAlias(ctx context.Context, publicKey string, hint string) (*model
 	return &r, nil
 }
 
+// SendSMS calls the API to send out an SMS.
+// Parameters:
+//   - inviterPhone: The user initiating the SMS.
+//   - inviteePhone: The number being invited to Sarafu.
+func (as *HTTPAccountService) SendUpsellSMS(ctx context.Context, inviterPhone, inviteePhone string) (*models.SendSMSResponse, error) {
+	var r models.SendSMSResponse
+
+	// Create request payload
+	payload := map[string]string{
+		"inviterPhone": inviterPhone,
+		"inviteePhone": inviteePhone,
+	}
+
+	payloadBytes, err := json.Marshal(payload)
+	if err != nil {
+		return nil, err
+	}
+
+	// Create a new request
+	req, err := http.NewRequest("POST", config.SendSMSURL, bytes.NewBuffer(payloadBytes))
+	if err != nil {
+		return nil, err
+	}
+	_, err = doRequest(ctx, req, &r)
+	if err != nil {
+		return nil, err
+	}
+
+	return &r, nil
+}
+
 // TODO: remove eth-custodial api dependency
 func doRequest(ctx context.Context, req *http.Request, rcpt any) (*api.OKResponse, error) {
 	var okResponse api.OKResponse
diff --git a/testutil/mocks/service_mock.go b/testutil/mocks/service_mock.go
index bfa9222..b2cc015 100644
--- a/testutil/mocks/service_mock.go
+++ b/testutil/mocks/service_mock.go
@@ -53,7 +53,12 @@ func (m *MockAccountService) CheckAliasAddress(ctx context.Context, alias string
 	return args.Get(0).(*models.AliasAddress), args.Error(1)
 }
 
-func (m MockAccountService) RequestAlias(ctx context.Context, publicKey string, hint string) (*models.RequestAliasResult, error) {
+func (m *MockAccountService) RequestAlias(ctx context.Context, publicKey string, hint string) (*models.RequestAliasResult, error) {
 	args := m.Called(publicKey, hint)
 	return args.Get(0).(*models.RequestAliasResult), args.Error(1)
 }
+
+func (m *MockAccountService) SendUpsellSMS(ctx context.Context, inviterPhone, inviteePhone string) (*models.SendSMSResponse, error) {
+	args := m.Called(inviterPhone, inviteePhone)
+	return args.Get(0).(*models.SendSMSResponse), args.Error(1)
+}
diff --git a/testutil/testservice/account_service.go b/testutil/testservice/account_service.go
index 12b9de4..1d1e9f3 100644
--- a/testutil/testservice/account_service.go
+++ b/testutil/testservice/account_service.go
@@ -64,3 +64,7 @@ func (m TestAccountService) CheckAliasAddress(ctx context.Context, alias string)
 func (m TestAccountService) RequestAlias(ctx context.Context, publicKey string, hint string) (*models.RequestAliasResult, error) {
 	return &models.RequestAliasResult{}, nil
 }
+
+func (m TestAccountService) SendUpsellSMS(ctx context.Context, inviterPhone, inviteePhone string) (*models.SendSMSResponse, error) {
+	return &models.SendSMSResponse{}, nil
+}