AWS Lambda is a serverless computing service that runs your code in response to events and automatically manages the underlying compute resources. With Lambda, you can run code without provisioning or managing servers. You pay only for the compute time you consume - there's no charge when your code isn't running. Lambda can automatically scale your application by running code in response to each trigger, whether it's a few requests per day or thousands per second. Lambda supports multiple programming languages and is commonly used for real-time file processing, data transformation, and building backends for web, mobile, and IoT applications.