diff --git a/silkaj/constants.py b/silkaj/constants.py
index f941a370a8d9b361e2fc0e999778043de7a882c7..bd47f463e2bcc46e3bbdf8e66dcf37b33bad1526 100644
--- a/silkaj/constants.py
+++ b/silkaj/constants.py
@@ -32,3 +32,11 @@ MINIMAL_ABSOLUTE_TX_AMOUNT = 0.01
 MINIMAL_RELATIVE_TX_AMOUNT = 1e-6
 CENT_MULT_TO_UNIT = 100
 SHORT_PUBKEY_SIZE = 8
+
+# pendulum constants
+# see https://pendulum.eustace.io/docs/#localized-formats
+DATE = "LL"
+HOUR = "LTS"
+ALL = "LLL"
+# Not ISO 8601 compliant but common
+ALL_DIGITAL = "YYYY-MM-DD HH:mm:ss"