diff --git a/api/s5/messages.go b/api/s5/messages.go
index 845772d..b90bcc0 100644
--- a/api/s5/messages.go
+++ b/api/s5/messages.go
@@ -127,5 +127,6 @@ type AccountPinResponse struct {
 
 type AccountPin struct {
 	Hash     string `json:"hash"`
+	Size     uint64 `json:"size"`
 	MimeType string `json:"mime_type"`
 }
diff --git a/api/s5/s5.go b/api/s5/s5.go
index 1fb0e53..7e236d7 100644
--- a/api/s5/s5.go
+++ b/api/s5/s5.go
@@ -858,6 +858,7 @@ func (s *S5API) accountPins(jc jape.Context) {
 		}
 		pins[i] = AccountPin{
 			Hash:     base64Url,
+			Size:     pin.Upload.Size,
 			MimeType: pin.Upload.MimeType,
 		}
 	}
diff --git a/api/s5/swagger.yaml b/api/s5/swagger.yaml
index 0fa78d1..ad5b46b 100644
--- a/api/s5/swagger.yaml
+++ b/api/s5/swagger.yaml
@@ -911,10 +911,13 @@ components:
             type: object
             required:
                 - hash
+                - size
                 - mime_type
             properties:
                 hash:
                     type: string
+                size:
+                    type: integer
                 mime_type:
                     type: string
         RegistryQueryResponse: