diff --git a/server/json_encoder.py b/server/json_encoder.py
index dee3c53..b5eb05a 100644
--- a/server/json_encoder.py
+++ b/server/json_encoder.py
@@ -4,8 +4,8 @@
 
 
 def _encode_time(time):
-    """Encodes time in YYYYMMDDTHHMMSSZ format (assumes UTC time zone)."""
-    return datetime.datetime.strftime(time, '%Y%m%dT%H%M%SZ')
+    """Encodes time in YYYYMMDDTHHMMZ format (assumes UTC time zone)."""
+    return datetime.datetime.strftime(time, '%Y%m%dT%H%MZ')
 
 
 class Encoder(simplejson.JSONEncoder):
diff --git a/tests/test_json_encoder.py b/tests/test_json_encoder.py
index 83f7f90..c08dd08 100644
--- a/tests/test_json_encoder.py
+++ b/tests/test_json_encoder.py
@@ -22,60 +22,60 @@ def test_encodes_records_correctly(self):
         self.assertJsonEqual(
             """
             {
-              "timestamp": "20170319T150123Z",
+              "timestamp": "20170319T1501Z",
               "soil_moisture": 305
             }
             """.strip(),
             self.encoder.encode(
                 db_store.SoilMoistureRecord(
                     timestamp=datetime.datetime(
-                        2017, 3, 19, 15, 1, 23, 924000, tzinfo=pytz.utc),
+                        2017, 3, 19, 15, 1, tzinfo=pytz.utc),
                     soil_moisture=305)))
         self.assertJsonEqual(
             """
             {
-              "timestamp": "20170319T150123Z",
+              "timestamp": "20170319T1501Z",
               "ambient_light": 87.3
             }
             """.strip(),
             self.encoder.encode(
                 db_store.AmbientLightRecord(
                     timestamp=datetime.datetime(
-                        2017, 3, 19, 15, 1, 23, 924000, tzinfo=pytz.utc),
+                        2017, 3, 19, 15, 1, tzinfo=pytz.utc),
                     ambient_light=87.3)))
         self.assertJsonEqual(
             """
             {
-              "timestamp": "20170319T150123Z",
+              "timestamp": "20170319T1501Z",
               "humidity": 21.5
             }
             """.strip(),
             self.encoder.encode(
                 db_store.HumidityRecord(
                     timestamp=datetime.datetime(
-                        2017, 3, 19, 15, 1, 23, 924000, tzinfo=pytz.utc),
+                        2017, 3, 19, 15, 1, tzinfo=pytz.utc),
                     humidity=21.5)))
         self.assertJsonEqual(
             """
             {
-              "timestamp": "20170319T150123Z",
+              "timestamp": "20170319T1501Z",
               "temperature": 21.5
             }
             """.strip(),
             self.encoder.encode(
                 db_store.TemperatureRecord(
                     timestamp=datetime.datetime(
-                        2017, 3, 19, 15, 1, 23, 924000, tzinfo=pytz.utc),
+                        2017, 3, 19, 15, 1, tzinfo=pytz.utc),
                     temperature=21.5)))
         self.assertJsonEqual(
             """
             {
-              "timestamp": "20170319T150123Z",
+              "timestamp": "20170319T1501Z",
               "water_pumped": 302.5
             }
             """.strip(),
             self.encoder.encode(
                 db_store.WateringEventRecord(
                     timestamp=datetime.datetime(
-                        2017, 3, 19, 15, 1, 23, 924000, tzinfo=pytz.utc),
+                        2017, 3, 19, 15, 1, tzinfo=pytz.utc),
                     water_pumped=302.5)))