diff --git a/src/ingress_grpc/proto/dev/restate/services.proto b/src/ingress_grpc/proto/dev/restate/services.proto
new file mode 100644
index 000000000..ee2652dfb
--- /dev/null
+++ b/src/ingress_grpc/proto/dev/restate/services.proto
@@ -0,0 +1,35 @@
+/*
+  This package provides interfaces for built-in services
+ */
+syntax = "proto3";
+
+package dev.restate;
+
+option java_multiple_files = true;
+option java_package = "dev.restate.generated";
+option go_package = "restate.dev/sdk-go/pb";
+
+service Ingress {
+  // Invoke a service and don't wait for the response.
+  // It is guaranteed that the service will be invoked after this method returns.
+  rpc Invoke(InvokeRequest) returns (InvokeResponse);
+}
+
+message InvokeRequest {
+  // Fully qualified name of the service, e.g. `counter.Counter`
+  string service = 1;
+  // Method name of the service to invoke, e.g. `Add`
+  string method = 2;
+  // Argument of the invocation.
+  // When executing requests to the ingress using Protobuf,
+  // this field must contain the serialized Protobuf matching the argument type of the target method.
+  // When executing requests to the ingress using JSON,
+  // this field must contain the JSON object representing the argument type of the target method.
+  bytes argument = 3;
+}
+
+message InvokeResponse {
+  // Generated unique invocation identifier.
+  // It can be used to retrieve the status of the invocation and cancel it.
+  string sid = 1;
+}
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