diff --git a/github/client.go b/github/client.go
new file mode 100644
index 0000000..ae63c4c
--- /dev/null
+++ b/github/client.go
@@ -0,0 +1,21 @@
+package github
+
+import (
+	"net/http"
+	"strconv"
+	"time"
+)
+
+func ParseRetryAfter(resp *http.Response) time.Duration {
+	v := resp.Header.Get("Retry-After")
+	if v == "" {
+		return 0
+	}
+	if sec, err := strconv.Atoi(v); err == nil {
+		return time.Duration(sec) * time.Second
+	}
+	if t, err := time.Parse(http.TimeFormat, v); err == nil {
+		return time.Until(t)
+	}
+	return 0
+}