UCLouvain UCLouvain UCLouvain UCLouvain UCLouvain The extensibility of Internet protocols is a key factor to their success. Yet, their implementations are often not designed with agility in mind. In this document, we leverage the features of the QUIC protocol and propose a solution to dynamically extend QUIC implementations. Our solution relies on QUIC Plugins that allow tuning and extending the QUIC protocol on a per-connection basis. These platform-independent plugins are executed inside a sandboxed environment which can be included in QUIC implementations. We describe how such plugins can be used in different use cases. This document is a straw-man proposal. It aims at sparking discussions on the proposed approach.