RustDesk is a full-featured, open-source remote desktop application written primarily in Rust with a Flutter frontend. In production, it enables remote control, file transfer, clipboard synchronization, audio/video streaming, TCP tunneling, printer sharing, and camera streaming across Windows, macOS, Linux, Android, and iOS. The architecture is a client-server model with a rendezvous/relay server for NAT traversal, a plugin system for extensibility, and platform-specific backends for screen capture (DXGI, X11, Wayland, Quartz, Android MediaProjection), input simulation (enigo), and clipboard file transfer (RDP-based protocol with FUSE on Unix). Key entry points include `src/main.rs` (CLI), `src/server.rs` (host service), `src/client.rs` (remote session), and the Flutter UI in `flutter/`. Data flows involve encrypted peer-to-peer connections (NaCl), adaptive video codec selection (VP8/VP9/AV1/H264/H265 with hardware acceleration), and IPC via named pipes with OS-level authentication. External dependencies include libvpx, libyuv, FFmpeg, Opus, and platform-specific SDKs (Windows IddCx, macOS CoreGraphics, Linux Wayland/D-Bus). The codebase is actively maintained with frequent commits, CI/CD pipelines, and a large community (120k+ stars).
Aspia is a comprehensive, cross-platform remote desktop and system administration suite. The codebase is decomposed into four primary components: a **host** (the machine being controlled), a **client** (the controlling machine), a **router** (session brokering and NAT traversal), and a **relay** (traffic forwarding). It supports Windows, Linux, macOS, and Android, with platform-specific implementations for screen capture (DXGI, X11, Wayland/PipeWire, KMS/DRM, Android MediaProjection), audio (WASAPI, PulseAudio, Oboe), input injection, and clipboard integration. The system uses encrypted communication with SRP authentication, X25519 key exchange, and AEAD ciphers (AES-256-GCM, ChaCha20-Poly1305) with key ratcheting. Beyond desktop sharing, it provides file transfer, text chat, remote terminal, task manager, system information collection, and video recording. The client features both a Qt-based desktop GUI and a custom Android UI built with native widgets. The router manages host discovery, two-factor authentication (TOTP), and relay session keys, while the relay handles peer-to-peer forwarding. The codebase is built with CMake, uses protobuf for messaging, and relies on libraries like asio, OpenSSL, libvpx, libyuv, and zstd.