The Jamstack architecture allows for custom backends to be used with Jamstack apps, which can be beneficial in certain situations. In this tutorial series, a complete custom backend is built using Strapi, and then a Jamstack app is created to read and write data from the backend. The process involves deploying a new Strapi instance on DigitalOcean, setting up the backend with data collection types for corgis and reactions, configuring access permissions, and creating content types in the Strapi dashboard. With no code required, the custom backend is successfully deployed, allowing for future development of a Jamstack app to interact with it.