Open Source Reliable-UDP Libraries

Hysteria is a high-performance, censorship-resistant proxy and VPN-like networking tool designed to deliver fast, reliable connectivity over unstable or lossy networks by leveraging a custom UDP/QUIC-based transport layer that can masquerade as standard HTTP/3 traffic to evade detection. It supports a wide range of use cases including SOCKS5 and HTTP proxying, TCP/UDP forwarding, Linux TProxy for network redirection, and even tunneling via TUN interfaces, making it a flexible choice for developers and network engineers needing robust remote access or traffic obfuscation. Because it’s implemented in Go and MIT-licensed, the project provides cross-platform builds for major operating systems and architectures, letting users deploy servers and clients for both personal and infrastructural purposes.

kcptun is a stable and secure tunnel based on KCP with N:M multiplexing and FEC. Available for ARM, MIPS, 386 and AMD64. kcptun is shipped with builtin packet encryption powered by various block encryption algorithms and works in Cipher Feedback Mode, for each packet to be sent, the encryption process will start from encrypting a nonce from the system entropy, so encryption to same plaintexts never leads to a same ciphertexts thereafter. kcptun made use of ReedSolomon-Codes to recover lost packets, which requires massive amount of computation, a low-end ARM device cannot satisfy kcptun well. To unleash the full potential of kcptun, a multi-core x86 homeserver CPU like AMD Opteron is recommended. If you insist on running under some ARM routers, you'd better turn off FEC and use salsa20 as the encryption method.

Efficient reliable UDP unicast, UDP multicast, and IPC message transport. Java and C++ clients are available in this repository, and a .NET client is available from a 3rd party. All three clients can exchange messages across machines, or on the same machine via IPC, very efficiently. Message streams can be recorded by the Archive module to persistent storage for later, or real-time, replay. Aeron Cluster provides support for fault-tolerant services as replicated state machines based on the Raft consensus algorithm. Performance is the key focus. A design goal for Aeron is to be the highest throughput with the lowest and most predictable latency of any messaging system. Aeron integrates with Simple Binary Encoding (SBE) for the best possible message encoding and decoding performance. Many of the data structures used in the creation of Aeron have been factored out to the Agrona project.

Agrona provides a library of data structures and utility methods that are a common need when building high-performance applications in Java. Many of these utilities are used in the Aeron efficient reliable UDP unicast, multicast, and IPC message transport and provides high-performance buffer implementations to support the Simple Binary Encoding Message Codec.

An object-oriented implementation of a reliable, in-order, transport protocol over UDP based on the Internet Draft by Bova, Krivoruchka, and Cisco Systems (1999) titled "Reliable UDP".

FBNetwork is a high-performance, windows based, C++ library. It supports reliable UDP connection(which can ensure the sequence and arrival of the packages) based on datagram/data stream, NAT traversing, asynchronization and blocking, message handling.

Lite reliable UDP library for .NET Framework 3.5, Mono, .NET Core 2.0, .NET Standard 2.0. Small packet size overhead (1 byte for unreliable, 3 bytes for reliable packets). Helper classes for sending and reading messages. Always use library sources instead of precompiled DLL files (because there are platform-specific #ifdefs and workarounds for unity bugs). Fast packet serializer (Usage manual). Automatic small packets merging. Automatic fragmentation of reliable packets. Automatic MTU detection. UDP NAT hole punching. NTP time requests. Packet loss and latency simulation. IPv6 support (dual mode). Connection statisitcs (need DEBUG or STATS_ENABLED flag). Multicasting (for discovering hosts in local network). Unity support.

Combined client+server UDP based file transfer application. Based on the UDT protocol - via libudt - http://udt.sourceforge.net/ UDT is a reliable UDP based application level data transport protocol. UDT is designed for extremely high speed networks and it has been used to support global data transfer of terabyte sized data sets. Ne Plus Ultra is built to have extremely minimal dependencies (statically linked against libudt.a) to ensure maximum portability and ease of use. https://github.com/bcwinters/neplusultra

A simple cross-platform resending (reliable) UDP packet library written in C++.

A cross platform and multithreaded reliable UDP library written in C++.

P2engine is a flexible and efficient platform for making p2p system development easier. Reliable UDP, Message Transport , Message Dispatcher, Fast and Safe Signal/Slot...

Supported protocol: TCP, UDP, RUDP (Reliable UDP), RICMP (Reliable ICMP), RHTTP (Reliable HTTP), KCP, Quic. Support type: forward proxy, reverse agent, SOCKS5 forward agent, SOCKS5 reverse agent. Agreement and type can be freely combined. External agent agreement and internal forwarding protocols can freely combine. Support Shadowsocks plug-in, spp-shadowsocks-plugin, spp-shadowsocks-plugin-android.

udp network library project for game programming - udp game-server architecture - reliable udp (like TCP) - p2p (+udp tunneling)