As containerd reaches its fourth birthday, it has already been adopted as a container runtime underneath Kubernetes in public cloud providers and various developer tools and platforms. In this talk we'll look deeper at the architecture choices and clean API layer which has enabled further use of containerd as an embedded and extensible runtime in additional projects, like Amazon's Firecracker integration, Kata's use of the v2 shim API, and Microsoft Azure's creation of the Teleport registry feature. We'll also look at in-flight work with CERN, Google, and others around remote "pre-seeded" snapshotters which allow for significant speedups in container startup time with special-case clusters like CERN's compute cloud.