Push notifications or Web Hooks trigger alerts to seller applications when specific events occur, such as an item is unpublished, a new purchase order is created, an item's inventory is out of stock, etc. Whenever the trigger event occurs, Walmart will send a notification payload with event details to the seller-defined destination URL. Web Hooks help to optimize integration, automate workflows and reduce the number of times your application has to poll Walmart APIs within the throttle limits to determine if an event has occurred.