diff --git a/cmd/checkout/cart-client.go b/cmd/checkout/cart-client.go
index 55f060a..eb999aa 100644
--- a/cmd/checkout/cart-client.go
+++ b/cmd/checkout/cart-client.go
@@ -46,7 +46,7 @@ func NewCartClient(baseUrl string) *CartClient {
 
 func (s *CartClient) getCartGrain(ctx context.Context, cartId cart.CartId) (*cart.CartGrain, error) {
 	// Call cart service to get grain
-	url := fmt.Sprintf("%s/cart/byid/%d", s.baseUrl, cartId.String())
+	url := fmt.Sprintf("%s/cart/byid/%s", s.baseUrl, cartId.String())
 	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
 	if err != nil {
 		return nil, err