The developer platform popular for creating applications on Amazon Web Services (AWS) is AWS Lambda. This serverless computing service allows developers to run code for applications or backend services without provisioning or managing servers. With Lambda, developers can execute code in response to events such as changes in data and system state, enabling them to build scalable applications efficiently. The pay-as-you-go model helps reduce costs, as users only pay for the compute time consumed. This flexibility supports rapid development and deployment of cloud-based solutions.