Function as a Service (FaaS)

Function as a Service (FaaS) is a cloud computing model that provides a platform for executing event-triggered functions, allowing for automatic scaling without manual intervention. At its essence, FaaS enables the deployment of individual functions that are activated by specific events, operate on a short-term basis, and then shut down, ensuring resources are not wasted. This model supports an autoscaling feature, enabling a function instance to be initiated per request and terminated post-execution, emphasizing its stateless nature. Consequently, FaaS platforms can implement a true pay-as-you-go billing approach, eliminating costs when functions are dormant, distinguishing it from other models like Platform as a Service (PaaS), which require continuous resource availability.

Problem it addresses

Traditionally, businesses have relied on maintaining on-premises data centers, necessitating substantial investment in hardware, software, and personnel. This setup demands resources to be scaled to peak demand, resulting in underutilized assets during downtime. Moreover, rapid business growth can overwhelm IT capabilities, leading to operational inefficiencies. In contrast, Infrastructure-as-a-Service (IaaS) models, while offering cloud-based solutions, still place the onus of scaling resources on the user, requiring payment for continuous server availability irrespective of actual usage.

How it helps

FaaS gives developers an abstraction for running web applications in response to events, eliminating the need to manage server infrastructure. For example, an action such as uploading a file could trigger custom code that transcodes the file into various formats. The FaaS infrastructure automatically adjusts resources to match demand, freeing developers from the complexities of coding for scalability. Charges apply solely for the duration of computation, ensuring no costs accrue when functions are inactive.

For more information, refer to the Serverless glossary entry. Although “serverless” and “FaaS” are often used as interchangeable terms, they embody distinct concepts.