The blog post discusses the importance of build cache in optimizing the Docker build process, particularly when using Dockerfiles to create container images from source code. It explains how Docker caches each command's result during the build, allowing for faster subsequent builds if the cache remains valid. The cache invalidation occurs when changes to dependencies or application files are detected, prompting the re-execution of affected commands. The article suggests structuring Dockerfiles to place commands that change frequently at the end, to minimize cache invalidation. Furthermore, it describes how the Koyeb platform uses buildctl, a tool similar to Docker, to manage cache during deployments from GitHub repositories, enhancing efficiency by using a Docker registry as a cache. The platform allows for flexible deployments on high-performance microVMs globally, with options to use or skip cache based on deployment needs, and offers an introductory credit to encourage new users to try their service.