diff --git a/server/apis/v1/handler.go b/server/apis/v1/handler.go
index 7628ba7ad6..a5b8938350 100644
--- a/server/apis/v1/handler.go
+++ b/server/apis/v1/handler.go
@@ -94,57 +94,63 @@ func (h *handler) ListNamespaces(c *gin.Context) {
 
 // GetClusterSummary summarizes information of all the namespaces in a cluster and wrapped the result in a list.
 func (h *handler) GetClusterSummary(c *gin.Context) {
-	namespaces, err := getAllNamespaces(h)
+	type namespaceSummary struct {
+		pipelineSummary PipelineSummary
+		isbsvcSummary   IsbServiceSummary
+	}
+	var namespaceSummaryMap = make(map[string]namespaceSummary)
+
+	// get pipeline summary
+	pipelineList, err := h.numaflowClient.Pipelines("").List(context.Background(), metav1.ListOptions{})
 	if err != nil {
 		h.respondWithError(c, fmt.Sprintf("Failed to fetch cluster summary, %s", err.Error()))
 		return
 	}
-	var clusterSummary ClusterSummaryResponse
-	// TODO(API): need a more efficient solution
-	// Loop over the namespaces to get status
-	for _, ns := range namespaces {
-		// Fetch pipeline summary
-		pipelines, err := getPipelines(h, ns)
+	for _, pipeline := range pipelineList.Items {
+		var summary namespaceSummary
+		if value, ok := namespaceSummaryMap[pipeline.Namespace]; ok {
+			summary = value
+		}
+		status, err := getPipelineStatus(&pipeline)
 		if err != nil {
 			h.respondWithError(c, fmt.Sprintf("Failed to fetch cluster summary, %s", err.Error()))
 			return
 		}
-
-		var pipeSummary PipelineSummary
-		var pipeActiveSummary ActiveStatus
-		// Loop over the pipelines and get the status
-		for _, pl := range pipelines {
-			if pl.Status == PipelineStatusInactive {
-				pipeSummary.Inactive++
-			} else {
-				pipeActiveSummary.increment(pl.Status)
-
-			}
+		if status == PipelineStatusInactive {
+			summary.pipelineSummary.Inactive++
+		} else {
+			summary.pipelineSummary.Active.increment(status)
 		}
-		pipeSummary.Active = pipeActiveSummary
+		namespaceSummaryMap[pipeline.Namespace] = summary
+	}
 
-		// Fetch ISB service summary
-		isbSvcs, err := getIsbServices(h, ns)
-		if err != nil {
-			h.respondWithError(c, fmt.Sprintf("Failed to fetch cluster summary, %s", err.Error()))
-			return
+	// get isbsvc summary
+	isbsvcList, err := h.numaflowClient.InterStepBufferServices("").List(context.Background(), metav1.ListOptions{})
+	if err != nil {
+		h.respondWithError(c, fmt.Sprintf("Failed to fetch cluster summary, %s", err.Error()))
+		return
+	}
+	for _, isbsvc := range isbsvcList.Items {
+		var summary namespaceSummary
+		if value, ok := namespaceSummaryMap[isbsvc.Namespace]; ok {
+			summary = value
 		}
-
-		var isbSummary IsbServiceSummary
-		var isbActiveSummary ActiveStatus
-		// loop over the ISB services and get the status
-		for _, isb := range isbSvcs {
-			if isb.Status == ISBServiceStatusInactive {
-				isbSummary.Inactive++
-			} else {
-				isbActiveSummary.increment(isb.Status)
-			}
+		// TODO(API) : Get the current status of the ISB service
+		status := ISBServiceStatusHealthy
+		if status == ISBServiceStatusInactive {
+			summary.isbsvcSummary.Inactive++
+		} else {
+			summary.isbsvcSummary.Active.increment(status)
 		}
-		isbSummary.Active = isbActiveSummary
-		clusterSummary = append(clusterSummary, NewClusterSummary(ns, pipeSummary, isbSummary))
+		namespaceSummaryMap[isbsvc.Namespace] = summary
 	}
-	c.JSON(http.StatusOK, NewNumaflowAPIResponse(nil, clusterSummary))
 
+	// get cluster summary
+	var clusterSummary ClusterSummaryResponse
+	for name, summary := range namespaceSummaryMap {
+		clusterSummary = append(clusterSummary, NewClusterSummary(name, summary.pipelineSummary, summary.isbsvcSummary))
+	}
+	c.JSON(http.StatusOK, NewNumaflowAPIResponse(nil, clusterSummary))
 }
 
 // CreatePipeline is used to create a given pipeline