diff --git a/definitions.go b/definitions.go
index 1148ec3..9baf98e 100644
--- a/definitions.go
+++ b/definitions.go
@@ -111,7 +111,7 @@ type Campaign struct {
 	Clicks              uint64             `json:"clicks,omitempty"`
 	Currency            string             `json:"currency,omitempty"`
 	Description         string             `json:"description,omitempty"`
-	ExpiresAt           string             `json:"expires_at,omitempty"`
+	ExpiresAt           string             `json:"expires_at,omitempty"` // time.RFC3339
 	FundingAddress      string             `json:"funding_address,omitempty"`
 	Goals               []*Goal            `json:"goals,omitempty"`
 	ID                  uint64             `json:"id,omitempty"`
diff --git a/examples/examples.go b/examples/examples.go
index f6fd328..10a5df9 100644
--- a/examples/examples.go
+++ b/examples/examples.go
@@ -210,7 +210,7 @@ func main() {
 		PayPerClickRate:     0.01,
 		TargetURL:           "https://offers.tonicpow.com",
 		Title:               "TonicPow Offers",
-		ExpiresAt:           expiresAt.String(),
+		ExpiresAt:           expiresAt.Format(time.RFC3339),
 	}
 	if campaign, err = createCampaign(campaign, userSessionToken); err != nil {
 		os.Exit(1)