diff --git a/metrics/metrics.go b/metrics/metrics.go
index 3506496..d1ff8f6 100644
--- a/metrics/metrics.go
+++ b/metrics/metrics.go
@@ -10,7 +10,7 @@ var (
 		Name:    "pinpoint_request_duration_milliseconds",
 		Help:    "latency of a given service - operation",
 		Buckets: []float64{5, 10, 25, 50, 75, 100, 200, 500, 800, 1000, 3000, 5000},
-	}, []string{"service", "operation"})
+	}, []string{"service", "operation", "response_code"})
 
 	// RequestsTotal is the metric
 	RequestsTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
@@ -24,24 +24,26 @@ var (
 		Help: "number of websocket connections for a request by service",
 	}, []string{"service"})
 
-	// RequestBytesSum is the metric
-	RequestBytesSum = prometheus.NewGaugeVec(prometheus.GaugeOpts{
-		Name: "pinpoint_request_bytes_sum",
-		Help: "sum of bytes for a request by service - operation",
-	}, []string{"service", "operation"})
+	// RequestBytes is the metric
+	RequestBytes = prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Name:    "pinpoint_request_bytes",
+		Help:    "size of request bytes in a given service - operation",
+		Buckets: []float64{.5, 1, 5, 10, 25, 50, 100, 250, 500, 1000, 2500, 5000, 10000, 30000, 60000, 300000, 600000, 1800000, 3600000},
+	}, []string{"service", "operation", "response_code"})
 
-	// ResponseBytesSum is the metric
-	ResponseBytesSum = prometheus.NewGaugeVec(prometheus.GaugeOpts{
-		Name: "pinpoint_response_bytes_sum",
-		Help: "sum of bytes for a response by service - operation",
-	}, []string{"service", "operation"})
+	// ResponseBytes is the metric
+	ResponseBytes = prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Name:    "pinpoint_response_bytes",
+		Help:    "size of response bytes in a given service - operation",
+		Buckets: []float64{.5, 1, 5, 10, 25, 50, 100, 250, 500, 1000, 2500, 5000, 10000, 30000, 60000, 300000, 600000, 1800000, 3600000},
+	}, []string{"service", "operation", "response_code"})
 )
 
 func init() {
 	prometheus.MustRegister(RequestDurationMilliseconds)
 	prometheus.MustRegister(RequestsTotal)
-	prometheus.MustRegister(RequestBytesSum)
-	prometheus.MustRegister(ResponseBytesSum)
+	prometheus.MustRegister(RequestBytes)
+	prometheus.MustRegister(ResponseBytes)
 	prometheus.MustRegister(WebsocketConnections)
 	prometheus.MustRegister(prometheus.NewBuildInfoCollector())
 }