AWS Lambda

AWS Lambda is the premier serverless, event-driven compute service: Run code in response to triggers without provisioning or managing any infrastructure.

Lambda delivers a true serverless experience, executing your code only when needed and scaling automatically from zero to thousands of requests per second (RPS). You pay only for the compute time consumed, measured in millisecond increments, making it highly cost-efficient. The service is event-driven; functions (code blocks) are invoked by triggers from over 200 AWS services, including Amazon S3 for file uploads, Amazon DynamoDB for database changes, and Amazon API Gateway for web backends. Lambda supports multiple runtimes (e.g., Node.js, Python, Java, Go) and manages all underlying resources: OS patching, capacity provisioning, and logging. This allows developers to focus exclusively on application logic, accelerating deployment cycles and reducing operational overhead.

https://aws.amazon.com/lambda/