Built a distributed publish/subscribe message

Built a distributed publish/subscribe message broker from scratch using the QUIC protocol (RFC 9000) over UDP, replacing traditional TCP/WebSocket-based messaging with multiplexed, encrypted streams. Designed a zero-trust, certificate-based authentication layer using self-signed Ed25519 identities encoded into X.509 SAN fields, enabling mutual TLS (mTLS) peer verification with no certificate authority, passwords, or shared secrets. Built a topic-based message fan-out engine and custom binary wire protocol with double-indexed subscription routing and self-healing dead-peer cleanup, plus a live observability dashboard visualizing peer topology and message throughput.