Does Aftersell have a developer API?

Aftersell does not offer a general-purpose developer API for configuring the app. Due to the nature of working with Shopify’s Post Purchase API and Checkout Extensibility environments we’re limited in what we can edit, and all of the changes available to us are made in the app itself.

There is one public API: the Aftersell Strategies API. It evaluates a strategy against the context you send and returns the products to show. It is available on stores that have Aftersell Strategies enabled, and requests are authenticated with a store-specific API key you generate in the Aftersell admin and send in the X-Strategy-Api-Key header.