Any window from your Mac, on your iPhone and iPad

Sill lets you project any window from your Mac to your iPhone or iPad, enabling control via touch, trackpad, keyboard, or Apple Pencil. The Mac sends the window, encoded as HEVC video, to the Sill app on the device. Interaction like taps, clicks, scrolls, and keys travels back to the Mac. Both devices link over the same network, a USB cable, Direct Wireless Connection, or a VPN like Tailscale when disconnected.

No account or server is needed; the connection happens directly. Sill for Mac is a free, notarized download from getsill.app, while the app for iPhone and iPad is free on the App Store or can be built from source. The app features tailored layouts for iPad and iPhone Duo, displaying a single window or the entire desktop. Sill captures one window or the full desktop at a time and does not play Mac audio.

The clipboard supports text only, up to 256 KB, between apps with the feature enabled. The Mac must be awake and Sill open for the connection to work; it may not wake the Mac otherwise. After a restart, Sill opens only after the user logs in, requiring pairing of the iPhone or iPad. Only paired iPhones and iPads can connect unless pairing is disabled, allowing any device on the network to connect, still securely.

Pairing is required for Sill for Mac 0.4.0 and later to connect with older versions. Since version 0.5.1, the apps share a version number for each release. Earlier versions of Sill for Mac have unencrypted connections locally, but the current versions maintain encryption. Sill is free with no ads, tracking, or subscriptions. Developers can support the tool via GitHub Sponsors, but this does not add any features.

Building Sill requires a Mac with Xcode, SwiftPM, and an Apple Development identity. Running Sill without the --install flag builds the .app file, while --install signs the build with the developer's identity. Debug builds from the repository can establish pairing without --pairing, but should only be used for development. The App Store version of Sill for iPhone and iPad never establishes such a direct connection.

Developers can run a command-line version of Sill for testing, but this exposes the network to unpaired devices. Documentation covers development commands, pairing, security, and release procedures. The project welcomes issues, questions, and pull requests that adhere to its guidelines. Contributions must follow the Apache License 2.0. The code is maintained by Noah Saffer.