Table of Contents

Introduction

RustPlusApi is a C# library for the Rust+ companion API — the same API the official Rust+ mobile app uses to talk to a Rust game server. With it you can read server state, control smart devices, watch security cameras, chat with your team/clan, and receive push notifications, all from .NET.

There is no official public schema for the Rust+ protocol; it is reverse-engineered by the community. RustPlusApi is grandly inspired by liamcottle/rustplus.js.

The packages

The library is split so you only take the dependencies you need.

Package What it does Depends on
RustPlusApi Core WebSocket client with a typed Response<T> API: info, time, map, markers, team & clan chat, nexus auth, entities (smart switch / alarm / storage monitor) and the camera protocol. protobuf-net
RustPlusApi.Fcm Listens to Firebase Cloud Messaging for server/entity pairing and alarm notifications. protobuf-net, System.Text.Json
RustPlusApi.Fcm.Registration Acquires all the credentials natively (GCM check-in → Firebase → FCM → Expo → Steam → Rust Companion). Replaces the rustplus.js Node CLI. RustPlusApi.Fcm
RustPlusApi.Camera Renders camera frames (AppCameraRays) into images. RustPlusApi, SixLabors.ImageSharp 
graph LR
    subgraph Your app
        A[Your .NET code]
    end
    A --> Core["RustPlusApi<br/>(WebSocket client)"]
    A --> Fcm["RustPlusApi.Fcm<br/>(FCM listener)"]
    A --> Reg["RustPlusApi.Fcm.Registration<br/>(credential acquisition)"]
    A --> Cam["RustPlusApi.Camera<br/>(frame rendering)"]
    Reg --> Fcm
    Cam --> Core
    Core -- "WebSocket :companion port" --> S[(Rust server)]
    Fcm -- "MCS / FCM" --> G[(Google FCM)]
    Reg -- "HTTPS" --> X[(Google / Expo / Steam / Facepunch)]

Target frameworks

Everything targets .NET Standard 2.0 and .NET 10, so the libraries run on .NET Framework 4.6.2+, .NET 6–10, Mono and Unity. The net10.0 build uses modern BCL fast-paths; the netstandard2.0 build keeps the reach.

How it fits together

1. Get credentials once — RustPlusApi.Fcm.Registration drives the full chain: GCM check-in, Firebase installation, FCM token, Expo push token, an interactive Steam login via Chrome DevTools, and a Rust Companion device registration. The result is a rustplus.config.json you load on every subsequent run. After that, pairing a server in game pushes four values — server IP, companion port, your SteamID64, and a per-server token — straight to your app via FCM. See Credentials for the step-by-step flow.

2. Talk to the server — RustPlusApi opens a WebSocket to the companion port and exposes a typed Response<T> API: server info, time, map, markers, team and clan chat, smart entities, camera subscription, and Nexus cross-server auth. See RustPlus Client for the full surface.

3. Listen for notifications — RustPlusApi.Fcm maintains a persistent MCS connection to Google FCM and surfaces server-pairing events, smart-alarm triggers, and entity pairing notifications as strongly-typed .NET events. See FCM Notifications.

4. Render cameras (optional) — RustPlusApi.Camera converts the raw AppCameraRays protobuf frames from the WebSocket stream into images using SixLabors.ImageSharp. See Cameras.

Start with Getting Started.

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