Sill: Remote Window Streaming for Mac to iOS Devices
Stream Mac windows to iPhone or iPad with touch and peripheral support.
1Remote Window Access
Sill enables users to stream specific Mac windows or the entire desktop to an iPhone or iPad. The application supports interaction via touch, trackpad, keyboard, or Apple Pencil. It functions by capturing the Mac screen, encoding it as HEVC video, and transmitting the feed to the mobile device over a network connection.
2Connectivity and Security
The system operates without external servers or accounts, prioritizing privacy. Connections are established over local networks, USB cables, or peer-to-peer Wi-Fi via Direct Wireless Connection. For remote access, users can utilize their own VPNs like Tailscale. All traffic is secured using TLS 1.3 encryption, ensuring data remains private during the streaming process.
3Hardware and Software Requirements
The host requires a Mac with Apple silicon running macOS 14 or later. Mobile devices must run iOS 17 or iPadOS 17 or later. Users must grant Screen Recording and Accessibility permissions on the Mac to allow the app to capture windows and simulate mouse or keyboard inputs for remote control functionality.
4Performance Optimization Strategy
Sill utilizes ScreenCaptureKit and the Mac's hardware video encoder for efficient performance. To maintain a real-time experience, the system prioritizes low latency over image quality. If the link or encoder falls behind, the application drops frames rather than queuing them, ensuring the displayed picture remains current with the Mac's actual state.
5Advanced Input Handling
The app translates mobile inputs into Mac mouse and keyboard events. Users can perform complex gestures like three-finger swipes for Mission Control or App Exposé. The system also supports Apple Pencil as a pointer and allows external keyboards attached to the mobile device to type directly into the active Mac window.
6Device-Specific Layouts
Sill adapts its interface based on the device. On iPhone, it provides a layout with buttons and a trackpad below the stream. For iPhone Duo, the app follows the hinge, adjusting the display layout when the device is half-open or closed. Users can also resize window text for better readability on smaller screens.
7Clipboard and Integration
The application includes a bidirectional clipboard feature, allowing text copied on a Mac to be pasted on an iOS device and vice versa. This is limited to 256 KB of text per transfer. The feature is designed to respect security, ensuring that password managers marked as concealed remain protected on the Mac.
8Virtual Display Capabilities
Sill offers a virtual display feature that moves a streamed window onto a private display space on the Mac. This ensures the window continues to update even when covered by other applications. Because this uses a private macOS API, the software is distributed via the developer's website rather than the Mac App Store.
9Open Source Development
The project is open source under the Apache License 2.0 and built using Swift and Apple frameworks. Developers can build the app from source using Xcode 27 or later. The repository includes scripts for installation and testing, encouraging community contributions while maintaining strict conventions regarding third-party dependencies and server-less architecture.
10Project Sustainability Model
Sill is provided as free software with no advertisements, tracking, or subscription fees. The developer accepts support through GitHub Sponsors to cover developer account costs. This model emphasizes a community-driven approach where features remain free for all users, focusing on utility and privacy rather than monetization through traditional software sales channels.