diff --git a/app/__init__.py b/app/__init__.py
index e42bb7dc8..73082d14e 100644
--- a/app/__init__.py
+++ b/app/__init__.py
@@ -18,7 +18,7 @@ from app.clients.statsd.statsd_client import StatsdClient
 from app.encryption import Encryption
 
 
-DATETIME_FORMAT = "%Y-%m-%dT%H:%M:%S.%f"
+DATETIME_FORMAT = "%Y-%m-%dT%H:%M:%S.%fZ"
 DATE_FORMAT = "%Y-%m-%d"
 
 db = SQLAlchemy()
diff --git a/tests/app/celery/test_tasks.py b/tests/app/celery/test_tasks.py
index da4d5201c..f3654a8ef 100644
--- a/tests/app/celery/test_tasks.py
+++ b/tests/app/celery/test_tasks.py
@@ -76,7 +76,7 @@ def test_should_process_sms_job(sample_job, mocker):
         (str(sample_job.service_id),
          "uuid",
          "something_encrypted",
-         "2016-01-01T11:09:00.061258"),
+         "2016-01-01T11:09:00.061258Z"),
         queue="db-sms"
     )
     job = jobs_dao.dao_get_job_by_id(sample_job.id)
@@ -104,7 +104,7 @@ def test_should_process_sms_job_into_research_mode_queue_if_research_mode_servic
         (str(job.service_id),
          "uuid",
          "something_encrypted",
-         "2016-01-01T11:09:00.061258"),
+         "2016-01-01T11:09:00.061258Z"),
         queue="research-mode"
     )
 
@@ -133,7 +133,7 @@ def test_should_process_email_job_into_research_mode_queue_if_research_mode_serv
         (str(job.service_id),
          "uuid",
          "something_encrypted",
-         "2016-01-01T11:09:00.061258"),
+         "2016-01-01T11:09:00.061258Z"),
         queue="research-mode"
     )
 
@@ -252,7 +252,7 @@ def test_should_process_email_job_if_exactly_on_send_limits(notify_db,
             str(job.service_id),
             "uuid",
             "something_encrypted",
-            "2016-01-01T11:09:00.061258"
+            "2016-01-01T11:09:00.061258Z"
         ),
         queue="db-email"
     )
@@ -294,7 +294,7 @@ def test_should_process_email_job(sample_email_job, mocker):
             str(sample_email_job.service_id),
             "uuid",
             "something_encrypted",
-            "2016-01-01T11:09:00.061258"
+            "2016-01-01T11:09:00.061258Z"
         ),
         queue="db-email"
     )
diff --git a/tests/app/invite/test_invite_rest.py b/tests/app/invite/test_invite_rest.py
index 9cf9c2f13..f76296d8c 100644
--- a/tests/app/invite/test_invite_rest.py
+++ b/tests/app/invite/test_invite_rest.py
@@ -55,7 +55,7 @@ def test_create_invited_user(notify_api, sample_service, mocker, invitation_emai
                 (str(current_app.config['NOTIFY_SERVICE_ID']),
                  'some_uuid',
                  encryption.encrypt(message),
-                 "2016-01-01T11:09:00.061258"),
+                 "2016-01-01T11:09:00.061258Z"),
                 queue="notify")
 
 
diff --git a/tests/app/user/test_rest.py b/tests/app/user/test_rest.py
index 8c87893aa..a6513e0f9 100644
--- a/tests/app/user/test_rest.py
+++ b/tests/app/user/test_rest.py
@@ -445,7 +445,7 @@ def test_send_user_reset_password_should_send_reset_password_link(notify_api,
                 [str(current_app.config['NOTIFY_SERVICE_ID']),
                  'some_uuid',
                  app.encryption.encrypt(message),
-                 "2016-01-01T11:09:00.061258"],
+                 "2016-01-01T11:09:00.061258Z"],
                 queue="notify")
 
 
@@ -525,7 +525,7 @@ def test_send_already_registered_email(notify_api, sample_user, already_register
                 (str(current_app.config['NOTIFY_SERVICE_ID']),
                  'some_uuid',
                  app.encryption.encrypt(message),
-                 "2016-01-01T11:09:00.061258"),
+                 "2016-01-01T11:09:00.061258Z"),
                 queue="notify")
 
 
@@ -573,7 +573,7 @@ def test_send_user_confirm_new_email_returns_204(notify_api, sample_user, change
                 str(current_app.config['NOTIFY_SERVICE_ID']),
                 "some_uuid",
                 app.encryption.encrypt(message),
-                "2016-01-01T11:09:00.061258"), queue="notify")
+                "2016-01-01T11:09:00.061258Z"), queue="notify")
 
 
 def test_send_user_confirm_new_email_returns_400_when_email_missing(notify_api, sample_user, mocker):
diff --git a/tests/app/user/test_rest_verify.py b/tests/app/user/test_rest_verify.py
index f38575b55..006247292 100644
--- a/tests/app/user/test_rest_verify.py
+++ b/tests/app/user/test_rest_verify.py
@@ -248,7 +248,7 @@ def test_send_user_sms_code(notify_api,
                 ([current_app.config['NOTIFY_SERVICE_ID'],
                   "some_uuid",
                   encrypted,
-                  "2016-01-01T11:09:00.061258"]),
+                  "2016-01-01T11:09:00.061258Z"]),
                 queue="notify"
             )
 
@@ -288,7 +288,7 @@ def test_send_user_code_for_sms_with_optional_to_field(notify_api,
                 ([current_app.config['NOTIFY_SERVICE_ID'],
                   "some_uuid",
                   encrypted,
-                  "2016-01-01T11:09:00.061258"]),
+                  "2016-01-01T11:09:00.061258Z"]),
                 queue="notify"
             )
 
@@ -343,7 +343,7 @@ def test_send_user_email_verification(notify_api,
                 (str(current_app.config['NOTIFY_SERVICE_ID']),
                  'some_uuid',
                  encryption.encrypt(message),
-                 "2016-01-01T11:09:00.061258"),
+                 "2016-01-01T11:09:00.061258Z"),
                 queue="notify")