Telepresence allows developers to test Kubernetes applications locally on their laptop for a fast development workflow. It works by replacing deployments with a proxy that redirects traffic to the local machine, providing access to cluster resources and unlimited compute. This avoids the slow process of building containers and deploying to the cluster for each change. The developer's laptop joins the cluster network namespace, allowing local tools to integrate seamlessly. Telepresence is an open source CNCF project that is actively developed to support additional features like multi-user development and persistent proxy deployments.