diff --git a/api/server-server/definitions/keys.yaml b/api/server-server/definitions/keys.yaml
index 2f1542367..679082686 100644
--- a/api/server-server/definitions/keys.yaml
+++ b/api/server-server/definitions/keys.yaml
@@ -66,7 +66,7 @@ properties:
         expired_ts:
           type: integer
           format: int64
-          description: POSIX timestamp for when this key expired.
+          description: POSIX timestamp in milliseconds for when this key expired.
           required: true
           example: 922834800000
         key:
diff --git a/api/server-server/keys_query.yaml b/api/server-server/keys_query.yaml
index f6e2cb196..8fbe00dc9 100644
--- a/api/server-server/keys_query.yaml
+++ b/api/server-server/keys_query.yaml
@@ -51,8 +51,8 @@ paths:
           type: integer
           format: int64
           description: |-
-            A millisecond POSIX timestamp indicating when the returned certificates
-            will need to be valid until to be useful to the requesting server.
+            A millisecond POSIX timestamp in milliseconds indicating when the returned 
+            certificates will need to be valid until to be useful to the requesting server.
 
             If not supplied, the current time as determined by the notary server is used.
           required: false
@@ -111,9 +111,9 @@ paths:
                         type: integer
                         format: int64
                         description: |-
-                          A millisecond POSIX timestamp indicating when the returned 
-                          certificates will need to be valid until to be useful to the 
-                          requesting server.
+                          A millisecond POSIX timestamp in milliseconds indicating when
+                          the returned certificates will need to be valid until to be 
+                          useful to the requesting server.
 
                           If not supplied, the current time as determined by the notary
                           server is used.