diff --git a/core/datasource/src/main/java/com/tangem/datasource/api/express/TangemExpressApi.kt b/core/datasource/src/main/java/com/tangem/datasource/api/express/TangemExpressApi.kt
index 469ab8a516..a57712606b 100644
--- a/core/datasource/src/main/java/com/tangem/datasource/api/express/TangemExpressApi.kt
+++ b/core/datasource/src/main/java/com/tangem/datasource/api/express/TangemExpressApi.kt
@@ -16,27 +16,27 @@ interface TangemExpressApi {
     @POST("assets")
     suspend fun getAssets(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
         @Body body: AssetsRequestBody,
     ): ApiResponse<List<Asset>>
 
     @POST("pairs")
     suspend fun getPairs(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
         @Body body: PairsRequestBody,
     ): ApiResponse<List<SwapPair>>
 
     @GET("providers")
     suspend fun getProviders(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
     ): ApiResponse<List<ExchangeProvider>>
 
     @GET("exchange-quote")
     suspend fun getExchangeQuote(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
         @Query("fromContractAddress") fromContractAddress: String,
         @Query("fromNetwork") fromNetwork: String,
         @Query("toContractAddress") toContractAddress: String,
@@ -51,7 +51,7 @@ interface TangemExpressApi {
     @GET("exchange-data")
     suspend fun getExchangeData(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
         @Query("fromContractAddress") fromContractAddress: String,
         @Query("fromNetwork") fromNetwork: String,
         @Query("toContractAddress") toContractAddress: String,
@@ -71,14 +71,14 @@ interface TangemExpressApi {
     @GET("exchange-status")
     suspend fun getExchangeStatus(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
         @Query("txId") txId: String,
     ): ApiResponse<ExchangeStatusResponse>
 
     @POST("exchange-sent")
     suspend fun exchangeSent(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
         @Body body: ExchangeSentRequestBody,
     ): ApiResponse<ExchangeSentResponseBody>
 }
\ No newline at end of file
diff --git a/core/datasource/src/main/java/com/tangem/datasource/api/onramp/OnrampApi.kt b/core/datasource/src/main/java/com/tangem/datasource/api/onramp/OnrampApi.kt
index 360e713a62..01d636242a 100644
--- a/core/datasource/src/main/java/com/tangem/datasource/api/onramp/OnrampApi.kt
+++ b/core/datasource/src/main/java/com/tangem/datasource/api/onramp/OnrampApi.kt
@@ -17,38 +17,38 @@ interface OnrampApi {
     @GET("currencies")
     suspend fun getCurrencies(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
     ): ApiResponse<List<OnrampCurrencyDTO>>
 
     @GET("countries")
     suspend fun getCountries(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
     ): ApiResponse<List<OnrampCountryDTO>>
 
     @GET("country-by-ip")
     suspend fun getCountryByIp(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
     ): ApiResponse<OnrampCountryDTO>
 
     @GET("payment-methods")
     suspend fun getPaymentMethods(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
     ): ApiResponse<List<PaymentMethodDTO>>
 
     @POST("onramp-pairs")
     suspend fun getPairs(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
         @Body body: OnrampPairsRequest,
     ): ApiResponse<List<OnrampPairDTO>>
 
     @GET("onramp-quote")
     suspend fun getQuote(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
         @Query("fromCurrencyCode") fromCurrencyCode: String,
         @Query("fromPrecision") fromPrecision: Int,
         @Query("toContractAddress") toContractAddress: String,
@@ -83,7 +83,7 @@ interface OnrampApi {
     @GET("onramp-status")
     suspend fun getStatus(
         @Header("user-id") userWalletId: String,
-        @Header("refcode") refCode: String,
+        @Header("refcode") refCode: String?,
         @Query("txId") txId: String,
     ): ApiResponse<OnrampStatusResponse>
 }
\ No newline at end of file
diff --git a/core/datasource/src/main/java/com/tangem/datasource/exchangeservice/swap/ExpressUtils.kt b/core/datasource/src/main/java/com/tangem/datasource/exchangeservice/swap/ExpressUtils.kt
index 50d0877467..d1176e7256 100644
--- a/core/datasource/src/main/java/com/tangem/datasource/exchangeservice/swap/ExpressUtils.kt
+++ b/core/datasource/src/main/java/com/tangem/datasource/exchangeservice/swap/ExpressUtils.kt
@@ -11,12 +11,12 @@ object ExpressUtils {
     private const val BATCH_ID_CHANGENOW = "BB000013"
     private const val BATCH_ID_PARTNER = "AF990015"
 
-    fun getRefCode(userWallet: UserWallet, appPreferencesStore: AppPreferencesStore): String {
+    fun getRefCode(userWallet: UserWallet, appPreferencesStore: AppPreferencesStore): String? {
         return when {
             isRing(userWallet, appPreferencesStore) -> "ring"
             isChangeNow(userWallet) -> "ChangeNow"
             isPartner(userWallet) -> "partner"
-            else -> ""
+            else -> null
         }
     }
 
diff --git a/data/onramp/src/main/java/com/tangem/data/onramp/DefaultOnrampRepository.kt b/data/onramp/src/main/java/com/tangem/data/onramp/DefaultOnrampRepository.kt
index b587d6f7e4..0260a3f859 100644
--- a/data/onramp/src/main/java/com/tangem/data/onramp/DefaultOnrampRepository.kt
+++ b/data/onramp/src/main/java/com/tangem/data/onramp/DefaultOnrampRepository.kt
@@ -372,7 +372,7 @@ internal class DefaultOnrampRepository(
                         refCode = ExpressUtils.getRefCode(
                             userWallet = userWallet,
                             appPreferencesStore = appPreferencesStore,
-                        ).takeUnless { it.isEmpty() },
+                        ),
                     ).bind()
                 },
                 onError = { e ->