AWS Lambda is the best fit for these requirements as it is a fully-managed, event-driven compute service that allows functions to be executed in response to HTTP requests through Amazon API Gateway or other trigger sources. Lambda is designed for short-duration, stateless functions, making it ideal for the scenario described. Other services like AWS Fargate and Amazon ECS also support serverless compute strategies, but they are container management services that are more suited for long-running and potentially stateful applications, rather than the event-driven, short-lived functions described in the scenario.