diff --git a/homeassistant/components/notify/aws_lambda.py b/homeassistant/components/notify/aws_lambda.py
index 7bb83db7f82..801537fbba6 100644
--- a/homeassistant/components/notify/aws_lambda.py
+++ b/homeassistant/components/notify/aws_lambda.py
@@ -15,6 +15,7 @@ from homeassistant.const import (
 from homeassistant.components.notify import (
     ATTR_TARGET, PLATFORM_SCHEMA, BaseNotificationService)
 import homeassistant.helpers.config_validation as cv
+from homeassistant.remote import JSONEncoder
 
 _LOGGER = logging.getLogger(__name__)
 REQUIREMENTS = ["boto3==1.4.3"]
@@ -38,7 +39,7 @@ PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
 def get_service(hass, config, discovery_info=None):
     """Get the AWS Lambda notification service."""
     context_str = json.dumps({'hass': hass.config.as_dict(),
-                              'custom': config[CONF_CONTEXT]})
+                              'custom': config[CONF_CONTEXT]}, cls=JSONEncoder)
     context_b64 = base64.b64encode(context_str.encode("utf-8"))
     context = context_b64.decode("utf-8")