diff --git a/src/core/mainloop/connection.c b/src/core/mainloop/connection.c
index ebf15fcc9e..3d551c4ba8 100644
--- a/src/core/mainloop/connection.c
+++ b/src/core/mainloop/connection.c
@@ -99,6 +99,7 @@
 #include "feature/hibernate/hibernate.h"
 #include "feature/hs/hs_common.h"
 #include "feature/hs/hs_ident.h"
+#include "feature/hs/hs_metrics.h"
 #include "feature/metrics/metrics.h"
 #include "feature/nodelist/nodelist.h"
 #include "feature/nodelist/routerlist.h"
@@ -4149,6 +4150,14 @@ connection_buf_read_from_socket(connection_t *conn, ssize_t *max_to_read,
      /* change *max_to_read */
     *max_to_read = at_most - n_read;
 
+    /* Onion service application connection. Note read bytes for metrics. */
+    if (CONN_IS_EDGE(conn) && TO_EDGE_CONN(conn)->hs_ident) {
+      edge_connection_t *edge_conn = TO_EDGE_CONN(conn);
+      hs_metrics_app_read_bytes(&edge_conn->hs_ident->identity_pk,
+                                edge_conn->hs_ident->orig_virtual_port,
+                                n_read);
+    }
+
     /* Update edge_conn->n_read */
     if (conn->type == CONN_TYPE_AP) {
       edge_connection_t *edge_conn = TO_EDGE_CONN(conn);
diff --git a/src/core/or/relay.c b/src/core/or/relay.c
index 6895591064..f986883370 100644
--- a/src/core/or/relay.c
+++ b/src/core/or/relay.c
@@ -83,6 +83,7 @@
 #include "feature/nodelist/describe.h"
 #include "feature/nodelist/routerlist.h"
 #include "core/or/scheduler.h"
+#include "feature/hs/hs_metrics.h"
 
 #include "core/or/cell_st.h"
 #include "core/or/cell_queue_st.h"
@@ -1689,6 +1690,13 @@ handle_relay_cell_command(cell_t *cell, circuit_t *circ,
         circuit_read_valid_data(TO_ORIGIN_CIRCUIT(circ), rh->length);
       }
 
+      /* For onion service connection, update the metrics. */
+      if (conn->hs_ident) {
+        hs_metrics_app_write_bytes(&conn->hs_ident->identity_pk,
+                                   conn->hs_ident->orig_virtual_port,
+                                   rh->length);
+      }
+
       stats_n_data_bytes_received += rh->length;
       connection_buf_add((char*)(cell->payload + RELAY_HEADER_SIZE),
                               rh->length, TO_CONN(conn));
diff --git a/src/feature/hs/hs_metrics.h b/src/feature/hs/hs_metrics.h
index 991b66a7ee..76eb68a2b1 100644
--- a/src/feature/hs/hs_metrics.h
+++ b/src/feature/hs/hs_metrics.h
@@ -35,4 +35,12 @@ void hs_metrics_update_by_service(const hs_metrics_key_t key,
 #define hs_metrics_new_introduction(s) \
   hs_metrics_update_by_service(HS_METRICS_NUM_INTRODUCTIONS, (s), 0, 1)
 
+/** Number of bytes written to the application from the service. */
+#define hs_metrics_app_write_bytes(i, port, n) \
+  hs_metrics_update_by_ident(HS_METRICS_APP_WRITE_BYTES, (i), (port), (n))
+
+/** Number of bytes read from the application to the service. */
+#define hs_metrics_app_read_bytes(i, port, n) \
+  hs_metrics_update_by_ident(HS_METRICS_APP_READ_BYTES, (i), (port), (n))
+
 #endif /* !defined(TOR_FEATURE_HS_HS_METRICS_H) */
diff --git a/src/feature/hs/hs_metrics_entry.c b/src/feature/hs/hs_metrics_entry.c
index d6b2e0e62b..6d0a143503 100644
--- a/src/feature/hs/hs_metrics_entry.c
+++ b/src/feature/hs/hs_metrics_entry.c
@@ -27,6 +27,20 @@ const hs_metrics_entry_t base_metrics[] =
     .help = "Total number of introduction received",
     .port_as_label = false,
   },
+  {
+    .key = HS_METRICS_APP_WRITE_BYTES,
+    .type = METRICS_TYPE_COUNTER,
+    .name = "hs_app_write_bytes_total",
+    .help = "Total number of bytes written to the application",
+    .port_as_label = true,
+  },
+  {
+    .key = HS_METRICS_APP_READ_BYTES,
+    .type = METRICS_TYPE_COUNTER,
+    .name = "hs_app_read_bytes_total",
+    .help = "Total number of bytes read from the application",
+    .port_as_label = true,
+  },
 };
 
 /** Size of base_metrics array that is number of entries. */
diff --git a/src/feature/hs/hs_metrics_entry.h b/src/feature/hs/hs_metrics_entry.h
index 96dce36ffa..e4b999fc46 100644
--- a/src/feature/hs/hs_metrics_entry.h
+++ b/src/feature/hs/hs_metrics_entry.h
@@ -17,6 +17,10 @@
 typedef enum {
   /** Number of introduction requests. */
   HS_METRICS_NUM_INTRODUCTIONS = 0,
+  /** Number of bytes written from onion service to application. */
+  HS_METRICS_APP_WRITE_BYTES = 1,
+  /** Number of bytes read from application to onion service. */
+  HS_METRICS_APP_READ_BYTES = 2,
 } hs_metrics_key_t;
 
 /** The metadata of an HS metrics. */