diff --git a/docs/server/source/drivers-clients/http-client-server-api.rst b/docs/server/source/drivers-clients/http-client-server-api.rst
index c57bb9c1..d84c0991 100644
--- a/docs/server/source/drivers-clients/http-client-server-api.rst
+++ b/docs/server/source/drivers-clients/http-client-server-api.rst
@@ -44,6 +44,11 @@ Transactions
    This endpoint returns only a transaction from a ``VALID`` or ``UNDECIDED``
    block on ``bigchain``, if exists.
 
+   A transaction itself doesn't include a ``timestamp`` property. Only the
+   block a transaction was included in has a unix ``timestamp`` property. It is
+   returned by this endpoint in a HTTP custom entity header called
+   ``X-BigchainDB-Timestamp``.
+
    :param tx_id: transaction ID
    :type tx_id: hex string
 
@@ -60,6 +65,7 @@ Transactions
 
       HTTP/1.1 200 OK
       Content-Type: application/json
+      X-BigchainDB-Timestamp: 1234567890
 
       {
         "transaction": {
@@ -107,6 +113,7 @@ Transactions
         "version": 1
       }
 
+   :resheader X-BigchainDB-Timestamp: A unix timestamp describing when a transaction was included into a valid block. The timestamp provided is taken from the block the transaction was included in.
    :resheader Content-Type: ``application/json``
 
    :statuscode 200: A transaction with that ID was found.