In this scenario, the best approach to satisfy the API-led connectivity principles and support future scalability is:
Experience APIs:
Create separate Experience APIs for the web application and the mobile application. This allows each application to have an optimized interface, supporting different needs and potential differences in request/response structures or security configurations.
Process API:
A single Process API can be used to orchestrate the workflow, including retrieving the email template from a database and preparing the email content. By centralizing this logic in the Process layer, we can ensure it is reusable and easily adaptable for different notification channels in the future.
System API:
A System API specifically designed for sending emails (using the Anypoint Connector for Email) abstracts the email-sending functionality from the business logic. This approach ensures that the email-sending function is reusable and scalable, and it can easily be extended or modified if other notification channels (like SMS or push notifications) are added later.
Why Option A is Correct:
This structure aligns with API-led connectivity principles by separating concerns across Experience, Process, and System layers. It provides flexibility for future notification channels and isolates each layer's responsibility, making it easier to maintain and scale.
of Incorrect Options:
Option B lacks a separate System API for sending emails, which goes against the principle of isolating back-end functionality in System APIs.
Option C similarly lacks a dedicated System API, reducing flexibility and reusability.
Option D suggests creating multiple Process APIs for database retrieval, which adds unnecessary complexity and does not adhere to the single-orchestration principle typically followed in API-led design.
Reference
For further guidance on API-led connectivity and the responsibilities of each API layer, refer to MuleSoft's documentation on API-led architecture and design best practices.