The Checkly CLI provides a JavaScript/TypeScript-native workflow for coding, testing and deploying synthetic monitoring at scale from your code repository. It solves problems encountered when shifting synthetic monitoring practices to the left by introducing resource constructs written in JavaScript or TypeScript that represent resources to be executed or created on the Checkly cloud backend. The CLI uses two core commands: test to run monitoring checks as tests in CI or on local machines, and deploy to push resources to the Checkly cloud and run them around the clock. This enables teams to integrate synthetic monitoring with their software development lifecycle (SLDC), moving from left to right through phases including analysis, design, development, testing, deployment, maintenance. The integration supports a broader monitoring as code workflow, tying together features like Checkly Code Explorer and Activity Log, which export resources created via the Web UI to CLI constructs or Terraform manifests, and track origin and update history with git commit attribution respectively. By using the Checkly CLI, teams can automate synthetic monitoring tasks, reduce manual work, increase productivity, and improve overall quality of their software.