Facebook Inc. Apple Inc. Apple Inc. Mozilla Google Facebook Inc. WebTransport [OVERVIEW] is a protocol framework that enables clients constrained by the Web security model to communicate with a remote server using a secure multiplexed transport. This document describes a WebTransport protocol that uses HTTP semantics to provide support for unidirectional streams, bidirectional streams, and datagrams. This protocol can be used with any HTTP version, however this document focuses on TCP-based HTTP versions, specifically providing examples of these capabilities when multiplexed within the same HTTP/2 [RFC7540] connection.