A protocol for secure client/server connections over UDP

netcode.io

netcode.io is a connection-oriented protocol built on top of UDP.

It’s designed for use in client/server games with dedicated servers.

It has the following security features:

• Protection against man-in-the-middle attacks.
• Protection against DDoS amplification attacks.
• Protection against packet replay attacks.
• Protection against zombie clients.

netcode.io has been used in several AAA game projects and is stable and mature.

How does it work?

Please refer to the second half of this whitepaper: Why can’t I send UDP packets from a browser?

For a complete technical specification, read the netcode 1.02 standard.

Source Code

This repository holds the implementation of netcode.io in C.

Other netcode.io repositories include:

• netcode.io C# implementation
• netcode.io Golang implementation
• netcode.io Rust implementation (updated fork of vvanders/netcode.io)
• netcode.io for Unity
• netcode.io for UE4
• netcode.io browser plugin

Contributors

These people are awesome:

• Val Vanders - Rust Implementation
• Walter Pearce - Rust Implementation
• Isaac Dawson - Golang Implementation
• June Rhodes - C# bindings, browser support, UE4 integration
• Alan Stagner - Unity integration, C# implementation
• Jérôme Leclercq - Support for random connect token nonce
• Randy Gaul - Discovered vulnerability in replay protection

Thanks for your contributions to netcode.io!

Author

The author of this library is Glenn Fiedler.

Glenn wrote an article series about the development of this library called Building a Game Network Protocol.

Other open source libraries by the same author include: yojimbo and reliable.io

Sponsors

netcode.io was generously sponsored by:

• Gold Sponsors

  • Remedy Entertainment
  • Cloud Imperium Games

• Silver Sponsors

  • Moon Studios
  • The Network Protocol Company

• Bronze Sponsors

  • Kite & Lightning
  • Data Realms

And by individual supporters on Patreon. Thank you. You made this possible!

License

BSD 3-Clause license.