> ## Documentation Index > Fetch the complete documentation index at: https://docs.colossal.sh/llms.txt > Use this file to discover all available pages before exploring further. # Storefront > Storefront cart and checkout events. Full list of cart and checkout events and their payload schemas. Storefront events fire when a shopper interacts with the cart or checkout. Storefront events trigger **sync automations**. This means they run on a user's critical path and must be fast and deterministic. Because of this, they have some contraints: * they can't use any of the Agent steps * they can't use `delay`, `wait_for_event`, `parallel`, `map` steps * they have execution timeout of **10 seconds** * only **one automation** can be active for each event Shopper PII in storefront event payloads is privacy-safe. Fields like `customer_email` can be null, and address details may be omitted when they are not needed for the event. ## Cart New shopping cart initialized. Unique cart identifier Item added to a cart. Unique cart identifier Added item details Total items in cart Cart subtotal Cart item quantity changed. Unique cart identifier Updated item details Previous quantity Total items in cart Cart subtotal Item removed from a cart. Unique cart identifier Removed item details Total items in cart Cart subtotal ## Checkout Checkout session initiated. Unique checkout session identifier Cart identifier (if from cart) Order identifier Checkout total Number of items Customer email Billing address provided during checkout. Unique checkout session identifier Order identifier Checkout total Customer email Billing address, when available Payment provider selected during checkout. Unique checkout session identifier Order identifier Checkout total Customer email Selected payment provider Previously selected provider Checkout completed successfully. Unique checkout session identifier Order identifier Checkout total Customer email Payment provider used Payment failed during checkout. Unique checkout session identifier Order identifier Checkout total Customer email Payment provider used Error code Error message Customer submitted a discount code at checkout. **Synchronous return** event — automation must produce a `DiscountValidationResult`. Unique checkout session identifier Order identifier The code the customer entered Order subtotal in dollars (used to compute percentage discounts) Currency code Customer email (for per-customer limits) Required automation output: Whether the code is accepted Echo of the submitted code How the discount is calculated Discount in cents (required when `discount_type=fixed_amount`) Whole-number percent off (required when `discount_type=percentage`, 0-100) Human-readable label shown at checkout Cap on total redemptions (null = unlimited) ## Shared Types Product identifier Product name Quantity in cart Price per unit Total for this line Street address Apartment, suite, etc. City State or province Postal/ZIP code Country code