Function as a service is a "platform-level cloud capability" that enables its users "to build and manage microservices applications with low initial investment for scalability," according to ISO/IEC 22123-2.
[2] The "Grain of Sand Anti-pattern" refers to the creation of excessively small components (e.g., functions) within a system, often resulting in increased complexity, operational overhead, and performance inefficiencies.
In contrast, published interfaces involve an explicit stability contract, including formal versioning, thorough documentation, a defined deprecation policy, and often support for backward compatibility.
Published interfaces may also require maintaining multiple versions simultaneously and adhering to formal deprecation processes when breaking changes are introduced.
However, this approach is noted to involve a steeper learning curve, and integration limitations may vary even within the same cloud vendor ecosystem.