diff --git a/email.go b/email.go
index 9d9a0d1..2877d19 100644
--- a/email.go
+++ b/email.go
@@ -69,7 +69,7 @@ type EmailResponse struct {
 	SubmittedAt time.Time
 	// MessageID: ID of message
 	MessageID string
-	// ErrorCode: API Error Codes
+	// ErrorCode: see error codes here (https://postmarkapp.com/developer/api/overview#error-codes)
 	ErrorCode int64
 	// Message: Response message
 	Message string
diff --git a/postmark.go b/postmark.go
index 60bf056..104df5c 100644
--- a/postmark.go
+++ b/postmark.go
@@ -102,7 +102,7 @@ func (client *Client) doRequest(ctx context.Context, opts parameters, dst interf
 
 // APIError represents errors returned by Postmark
 type APIError struct {
-	// ErrorCode: see error codes here (http://developer.postmarkapp.com/developer-api-overview.html#error-codes)
+	// ErrorCode: see error codes here (https://postmarkapp.com/developer/api/overview#error-codes)
 	ErrorCode int64
 	// Message contains error details
 	Message string