### Checkly uses AWS Lambda for its backend and has implemented a number of strategies to ensure scalability, low costs, and efficient use of resources. The company's Lambda setup includes three core functions that handle API checks, browser checks, and setup/teardown scripts, which are all triggered by SNS topics or directly via the AWS SDK. This approach allows for easy scaling and region-specific deployments without incurring additional costs. Checkly also uses Node-Lambda as a framework to package and deploy its Lambda functions, which provides a balance between simplicity and customization options. The company's background job setup utilizes SNS and SQS messaging to trigger Lambda functions, allowing for efficient and reliable processing of non-trivial tasks. Monitoring and logging on AWS Lambda are still evolving, with Checkly using third-party solutions like AppOptics to address limitations in the native AWS offerings.