RaphiMC

ViaVersion addon to add support for some notable Minecraft snapshots.

Open source minecraft authentication protocol for proxies

Minecraft Fabric mod which allows you to join EVERY Minecraft server version (Classic, Alpha, Beta, Release, April Fools, Bedrock)

Speed up immediate mode rendering in Minecraft

A BungeeCord plugin to fix compatibility issues with ViaProxy, enabling seamless multi-version support for backend servers with reduced overhead.