diff --git a/include/wsrep/applying_service.hpp b/include/wsrep/applying_service.hpp
new file mode 100644
index 0000000..40fb484
--- /dev/null
+++ b/include/wsrep/applying_service.hpp
@@ -0,0 +1,20 @@
+//
+// Copyright (C) 2018 Codership Oy <info@codership.com>
+//
+
+#ifndef WSREP_APPLYING_SERVICE_HPP
+#define WSREP_APPLYING_SERVICE_HPP
+
+namespace wsrep
+{
+    class applying_service
+    {
+    public:
+        virtual int start_transaction();
+        virtual int apply_write_set(const wsrep::const_buffer&) = 0;
+        virtual int apply_toi(const wsrep::const_buffer&);
+        virtual int apply_nbo(const wsrep::const_buffer&);
+    };
+}
+
+#endif // WSREP_APPLYING_SERVICE_HPP
diff --git a/include/wsrep/client_service.hpp b/include/wsrep/client_service.hpp
index 7763bdb..3c953fc 100644
--- a/include/wsrep/client_service.hpp
+++ b/include/wsrep/client_service.hpp
@@ -14,6 +14,8 @@
 #ifndef WSREP_CLIENT_SERVICE_HPP
 #define WSREP_CLIENT_SERVICE_HPP
 
+#include "transaction_termination_service.hpp"
+
 #include "buffer.hpp"
 #include "provider.hpp"
 #include "mutex.hpp"
@@ -22,7 +24,7 @@
 namespace wsrep
 {
     class transaction;
-    class client_service
+    class client_service : public wsrep::transaction_termination_service
     {
     public:
         client_service(wsrep::provider& provider)
@@ -76,17 +78,6 @@ namespace wsrep
          * Apply a write set.
          */
         virtual int apply(const wsrep::const_buffer&) = 0;
-
-        /**
-         * Commit transaction.
-         */
-        virtual int commit(const wsrep::ws_handle&, const wsrep::ws_meta&) = 0;
-
-        /**
-         * Roll back transaction.
-         */
-        virtual int rollback() = 0;
-
         //
         // Interface to global server state
         //
diff --git a/include/wsrep/transaction_termination_service.hpp b/include/wsrep/transaction_termination_service.hpp
new file mode 100644
index 0000000..886a377
--- /dev/null
+++ b/include/wsrep/transaction_termination_service.hpp
@@ -0,0 +1,21 @@
+//
+// Copyright (C) 2018 Codership Oy <info@codership.com>
+//
+
+
+#ifndef WSREP_TRANSACTION_TERMINATION_SERVICE_HPP
+#define WSREP_TRANSACTION_TERMINATION_SERVICE_HPP
+
+namespace wsrep
+{
+    class ws_handle;
+    class ws_meta;
+    class transaction_termination_service
+    {
+    public:
+        virtual int commit(const wsrep::ws_handle&, const wsrep::ws_meta&) = 0;
+        virtual int rollback() = 0;
+    };
+}
+
+#endif // WSREP_TRANSACTION_TERMINATION_SERVICE_HPP