Bluesky Social Bluesky Social Authenticated Transfer (AT) is a collection of protocol components that together provide a generic framework for interoperable social web applications, using global aggregations of interlinked, self- certifying data records. This informational document provides an overview of the entire system, as implemented in late 2025. Some of those components may be in scope as work for the IETF, while other components may not. Many components are general-purpose and may find use outside of the context of AT. The intent of this document is to provide context for how all the components can fit together for certain use cases.