diff --git a/apiary.apib b/apiary.apib
index 087b8af5..ff451e1b 100644
--- a/apiary.apib
+++ b/apiary.apib
@@ -980,7 +980,15 @@ In the cases where "serviceId" is part of URL "SERVICE_NAME" field at body can b
 
 ## Metrics [/v1.0/admin/metrics]
 
+The following metrics are collected by the component:
++ incomingTransactions: number of requests consumed by the component.
++ incomingTransactionRequestSize: total size (bytes) in requests associated to incoming transactions
++ incomingTransactionResponseSize: total size (bytes) in responses associated to incoming transactions
++ incomingTransacionError: number of incoming transactions resulting in error.
++ serviceTime: average time to serve a transaction.
+
 ### Get current metrics [GET]
+
 + Parameters
   + reset (optional, `string`) ... ["true", "false"]
 + Response 200 (application/json)
@@ -1002,7 +1010,17 @@ In the cases where "serviceId" is part of URL "SERVICE_NAME" field at body can b
                 "sum": {}
             }
           },
-          "sum": {}
+          "sum": {
+            "incomingTransactions": 25,
+            "incomingTransactionRequestSize": 3456,
+            "incomingTransactionResponseSize": 435,
+            "incomingTransacionError": 2,
+            "serviceTime": 0.48,
+            "outgoingTransactions": 46,
+            "outgoingTransactionRequestSize": 323361,
+            "outgoingTransactionResponseSize": 2343,
+            "outgoingTransacionError": 10
+          }
        }
 
 
@@ -1027,5 +1045,15 @@ In the cases where "serviceId" is part of URL "SERVICE_NAME" field at body can b
                 "sum": {}
             }
           },
-          "sum": {}
+          "sum": {
+            "incomingTransactions": 25,
+            "incomingTransactionRequestSize": 3456,
+            "incomingTransactionResponseSize": 435,
+            "incomingTransacionError": 2,
+            "serviceTime": 0.48,
+            "outgoingTransactions": 46,
+            "outgoingTransactionRequestSize": 323361,
+            "outgoingTransactionResponseSize": 2343,
+            "outgoingTransacionError": 10
+          }
        }