GGRS

Spec sheet

Purpose

GGRS is a Rust library for peer-to-peer rollback networking, described as a reimagination of the GGPO network SDK.Read 8 Oct 2026 · github.com

API

The project links to API documentation hosted on docs.rs.Read 8 Oct 2026 · github.com

Security

The project describes GGRS as written in 100% safe Rust.Read 8 Oct 2026 · github.com

License

GGRS is dual-licensed under MIT or Apache License 2.0, at the user's option.Read 8 Oct 2026 · github.com

Bevy plugin

The Bevy GGRS plugin advances game state and handles rollbacks through a dedicated schedule, snapshotting registered components and resources.Read 8 Oct 2026 · github.com

Browser support

The wasm-bindgen feature enables WebAssembly support for browser APIs, and the project points to Matchbox for WebRTC sockets.Read 8 Oct 2026 · github.com

Demo limitation

The project README says its hosted matchmaking server is currently offline, so the demos will not automatically find opponents.Read 8 Oct 2026 · github.com

Engine integrations

The project links to a Bevy plugin and a Godot wrapper; its demos use Macroquad and Bevy.Read 8 Oct 2026 · github.com

Game integration

Games provide state save and load operations and advance a frame using player inputs; GGRS handles input exchange, prediction, rollback scheduling, time synchronization, and desync detection.Read 8 Oct 2026 · docs.rs

Implementation

The project describes GGRS as written in 100% safe Rust.Read 8 Oct 2026 · github.com

Input prediction

Built-in predictors can repeat the last received input or predict the default input.Read 8 Oct 2026 · docs.rs

Intended audience

The project is aimed at developers integrating rollback networking into games, with examples and documentation for setup, sessions, the main loop, requests and events, and time synchronization.Read 8 Oct 2026 · github.com

Matchmaking integration

The project’s demos use Matchbox for WebRTC-based matchmaking, and its README says Matchbox sockets can work with GGRS through a feature flag.Read 8 Oct 2026 · github.com

Networking

GGRS supports a non-blocking UDP socket and a custom transport layer through its NonBlockingSocket trait.Read 8 Oct 2026 · docs.rs

Networking features

GGRS handles input exchange, prediction, rollback scheduling, time synchronization, and desync detection.Read 8 Oct 2026 · docs.rs

Project status

The README describes GGRS as fairly stable and says its core functionality for multiple players and spectators has not changed significantly in recent versions.Read 8 Oct 2026 · github.com

Rollback

GGRS predicts remote player inputs and, when they differ from received inputs, rolls back to a saved game state and simulates forward again.Read 8 Oct 2026 · docs.rs

Rollback operation

It predicts remote player inputs, detects mispredictions, rolls back to a saved state, and simulates forward again.Read 8 Oct 2026 · docs.rs

Session types

The library provides peer-to-peer multiplayer, spectator, and network-free sync-test sessions.Read 8 Oct 2026 · docs.rs

Setup requirement

A game using GGRS must save and load its state and advance one frame given player inputs.Read 8 Oct 2026 · docs.rs

Support and community

The README points developers to the GGPO Developers Discord to discuss rollback networking.Read 8 Oct 2026 · github.com

Where Specifiction places it

• Game Networking Middleware#19 of 297.7