diff --git a/protos/backend_service.proto b/protos/backend_service.proto
index ed96fa8..3426478 100644
--- a/protos/backend_service.proto
+++ b/protos/backend_service.proto
@@ -78,6 +78,9 @@ service BackendService {
 
     // Returns the current metrics for the backend service.
     rpc GetMetrics (GetMetricsRequest) returns (GetMetricsResponse);
+
+    rpc ListInstanceIDs (ListInstanceIDsRequest) returns (ListInstanceIDsResponse);
+    rpc GetInstanceHistory (GetInstanceHistoryRequest) returns (GetInstanceHistoryResponse);
 }
 
 // Request payload for adding new orchestration events.
diff --git a/protos/orchestrator_service.proto b/protos/orchestrator_service.proto
index 41fad9d..1fa4f14 100644
--- a/protos/orchestrator_service.proto
+++ b/protos/orchestrator_service.proto
@@ -739,6 +739,9 @@ service TaskHubSidecarService {
 
     // Rerun a Workflow from a specific event ID of a workflow instance.
     rpc RerunWorkflowFromEvent(RerunWorkflowFromEventRequest) returns (RerunWorkflowFromEventResponse);
+
+    rpc ListInstanceIDs (ListInstanceIDsRequest) returns (ListInstanceIDsResponse);
+    rpc GetInstanceHistory (GetInstanceHistoryRequest) returns (GetInstanceHistoryResponse);
 }
 
 message GetWorkItemsRequest {
@@ -820,3 +823,36 @@ message RerunWorkflowFromEventRequest {
 message RerunWorkflowFromEventResponse {
     string newInstanceID = 1;
 }
+
+// ListInstanceIDsRequest is used to list all orchestration instances.
+message ListInstanceIDsRequest {
+    // continuationToken is the continuation token to use for pagination. This
+    // is the token which the next page should start from. If not given, the
+    // first page will be returned.
+    optional string continuationToken = 1;
+
+    // pageSize is the maximum number of instances to return for this page. If
+    // not given, all instances will be attempted to be returned.
+    optional uint32 pageSize = 2;
+}
+
+// ListInstanceIDsResponse is the response to executing ListInstanceIDs.
+message ListInstanceIDsResponse {
+  // instanceIds is the list of instance IDs returned.
+  repeated string instanceIds = 1;
+
+  // continuationToken is the continuation token to use for pagination. If
+  // there are no more pages, this will be null.
+  optional string continuationToken = 2;
+}
+
+// GetInstanceHistoryRequest is used to get the full history of an
+// orchestration instance.
+message GetInstanceHistoryRequest {
+    string instanceId = 1;
+}
+
+// GetInstanceHistoryResponse is the response to executing GetInstanceHistory.
+message GetInstanceHistoryResponse {
+    repeated HistoryEvent events = 1;
+}