A Simple Web Service design pattern is one of the most standard use-cases of serverless cloud services like Function as a Service (Faas) like AWS Lambda by Amazon Web Service, Cloud Functions by Google Cloud and Azure Functions by Azure where these function as a service components of the cloud are designed as a backend service. It represents the logic or domain layer in an n-tiered application architecture.
For Public APIs, API Gateway exposes lambda functions via HTTP(s). API Gateway can handle authorization, authentication, routing, and versioning.
AWS Lambda scales automatically and can handle fluctuating loads. Execution time is limited to the maximum allowed by API Gateway (29 seconds), or the hard limit of 15 minutes if invoked with the SDK.
For internal APIs, clients invoke lambda functions directly from within the client app using AWS’ SDK.
It’s highly recommended that functions are stateless, sessions are cached and connections to downstream services are handled appropriately.