Which AWS service is primarily used for serverless application development?

AWS Lambda is fundamentally designed for serverless application development, allowing developers to run code without the need to manage servers. This service enables the execution of code in response to various triggers, such as HTTP requests, database changes, or file uploads. Consequently, it abstracts the underlying infrastructure, enabling developers to focus on writing and deploying their applications rather than worrying about server provisioning, scaling, or maintenance.

In a serverless architecture, AWS Lambda automatically scales the application by running code in response to events and managing the compute resources, which reflects the key characteristics of serverless computing—automatic scaling and pay-as-you-go pricing. This flexibility makes it ideal for applications that have variable workloads or require rapid development and deployment cycles.

Other services mentioned, such as AWS EC2, AWS RDS, and AWS CloudFormation, cater to different needs. AWS EC2 provides virtual servers for web hosting and is not serverless, requiring management of the underlying infrastructure. AWS RDS is a managed database service, which also involves server management, and AWS CloudFormation is used for infrastructure as code, facilitating the provisioning and management of cloud resources, rather than application execution itself. These distinctions underline why AWS Lambda stands out as the primary service for developing serverless applications.