Sequencing on Shopify is handled by the Nosto App when Category Merchandising is enabled through the user-interface. 

When creating a Sequence within Category Merchandising, Nosto directly modifies the source collection within Shopify by using the Shopify Admin API.

Learn more about creating sequences here: Get Started with Category Merchandising

When inspecting the modified collection within Shopify, the products are now sorted manually and the order is programatically determined via the configuration in the Category Merchandising Interface within Nosto.

When clicking on a product discovered through a Nosto Sequence a URL parameter will be present that denotes that the product was found through Category Merchandising, but also which Sequence it was discovered from. The attribution parameter will allow Nosto to calculate performance metrics such as views, clicks, sales etc. that happened through Category Merchandising. 

Attribution parameter will persist if a user interacts with filtering within the collection page, however if a user chooses another sorting method the attribution parameter is stripped from the URL. 

Syncing works behind an internal cache, meaning it can take up to 30mins before the syncing is activated. Usually it takes only a few minutes but be prepared for a delay.

Collections are updated every time you save, edit or delete a merchandising rule applied to a collection. There might be a small delay but in most cases the update is practically instantaneous. There is also an automatic update scheduled every 6hours to validate product attributes such as availability, pricing and overall ordering of items based on product performance.

Category Merchandising supports both regular, smart and custom collections. The difference between these is what products are part of the collection, whereas Nosto only influences the ordering of items through manipulating the manual sort order.