diff --git a/csharp/Momento.Protos.csproj b/csharp/Momento.Protos.csproj
index d881158b..ff661d84 100644
--- a/csharp/Momento.Protos.csproj
+++ b/csharp/Momento.Protos.csproj
@@ -24,6 +24,7 @@
     <Protobuf Include="../proto/cachepubsub.proto" GrpcServices="Client" />
     <Protobuf Include="../proto/token.proto" GrpcServices="Client" />
     <Protobuf Include="../proto/extensions.proto" GrpcServices="Client" />
+    <Protobuf Include="../proto/common.proto" GrpcServices="Client" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/proto/cacheclient.proto b/proto/cacheclient.proto
index 9b116397..ed772e5e 100644
--- a/proto/cacheclient.proto
+++ b/proto/cacheclient.proto
@@ -1,5 +1,7 @@
 syntax = "proto3";
 
+import "common.proto";
+
 option go_package = "github.com/momentohq/client-sdk-go;client_sdk_go";
 option java_multiple_files = true;
 option java_package = "grpc.cache_client";
@@ -21,6 +23,7 @@ service Scs {
   rpc GetBatch (_GetBatchRequest) returns (stream _GetResponse) {}
   rpc Set (_SetRequest) returns (_SetResponse) {}
   rpc SetBatch (_SetBatchRequest) returns (stream _SetResponse) {}
+  rpc SetIf (_SetIfRequest) returns (_SetIfResponse) {}
   rpc SetIfNotExists (_SetIfNotExistsRequest) returns (_SetIfNotExistsResponse) {}
   rpc Delete (_DeleteRequest) returns (_DeleteResponse) {}
   rpc KeysExist (_KeysExistRequest) returns (_KeysExistResponse) {}
@@ -124,6 +127,29 @@ message _SetBatchRequest {
   repeated _SetRequest items = 1;
 }
 
+message _SetIfRequest {
+  bytes cache_key = 1;
+  bytes cache_body = 2;
+  uint64 ttl_milliseconds = 3;
+  oneof condition {
+    common.Present present = 4;
+    common.PresentAndNotEqual present_and_not_equal = 5;
+    common.Absent absent = 6;
+    common.Equal equal = 7;
+    common.AbsentOrEqual absent_or_equal = 8;
+    common.NotEqual not_equal = 9;
+  }
+}
+
+message _SetIfResponse {
+  oneof result {
+    _Stored stored = 1;
+    _NotStored not_stored = 2;
+  }
+  message _Stored { }
+  message _NotStored { }
+}
+
 message _SetIfNotExistsRequest {
   bytes cache_key = 1;
   bytes cache_body = 2;
@@ -455,7 +481,7 @@ message _SetPopResponse {
   oneof set {
     _Found found = 1;
     _Missing missing = 2;
-  } 
+  }
 }
 
 message _ListConcatenateFrontRequest {
diff --git a/proto/common.proto b/proto/common.proto
new file mode 100644
index 00000000..cbfd6cf5
--- /dev/null
+++ b/proto/common.proto
@@ -0,0 +1,23 @@
+syntax = "proto3";
+
+package common;
+
+message Present { }
+
+message PresentAndNotEqual {
+  bytes value_to_check = 1;
+}
+
+message Absent { }
+
+message Equal {
+  bytes value_to_check = 1;
+}
+
+message AbsentOrEqual {
+  bytes value_to_check = 1;
+}
+
+message NotEqual {
+  bytes value_to_check = 1;
+}
diff --git a/rust/momento-protos/src/lib.rs b/rust/momento-protos/src/lib.rs
index 01cfb83c..e67fefb8 100644
--- a/rust/momento-protos/src/lib.rs
+++ b/rust/momento-protos/src/lib.rs
@@ -2,6 +2,10 @@ pub mod permission_messages {
   include!("permission_messages.rs");
 }
 
+pub mod common {
+  include!("common.rs");
+}
+
 pub mod auth {
   include!("auth.rs");
 }