diff --git a/README.md b/README.md
index 6388d4f..0b26763 100644
--- a/README.md
+++ b/README.md
@@ -154,7 +154,7 @@ aperiodic basis \
 
 ## Intervals
 
-`1m`, `5m`, `15m`, `30m`, `1h`, `4h`, `1d`
+`1s`, `1m`, `5m`, `15m`, `30m`, `1h`, `4h`, `1d`
 
 ## Output
 
diff --git a/types.go b/types.go
index 170e2e7..77204f4 100644
--- a/types.go
+++ b/types.go
@@ -10,6 +10,7 @@ const (
 type Interval string
 
 const (
+	Interval1s  Interval = "1s"
 	Interval1m  Interval = "1m"
 	Interval5m  Interval = "5m"
 	Interval15m Interval = "15m"