crmne/zapfast

ZapFast is an unofficial WhatsApp desktop client for Linux, macOS and Windows, written in Rust with egui and fastframe. It is aimed at people who want their WhatsApp chats in a native window instead of a browser tab, and who are willing to use a third-party client to get there.

What changes in everyday use

ZapFast links to your phone as a companion device through whatsapp-rust, not through a browser engine. In the author's Linux test it opens in under a second and uses about 200 MB idle RAM, compared with 1.13 GB for WhatsApp Web; the conditions are on the benchmark page. Chat history is kept in an encrypted archive on the computer, and older messages are fetched from the phone as you scroll. Once linked, the link survives restarts, so already-stored chats can be read even when the phone is offline.

The client covers text, replies, edits, reactions, forwards, media, stickers, GIFs, polls and voice messages, including in-chat playback. It supports several WhatsApp numbers in one window, keyboard shortcuts and cross-message text selection, tray notifications, light/dark/system/custom themes, and hiding locked chats or the whole window behind a code. The interface is localized into 10 languages, including Simplified and Traditional Chinese.

Getting it running

Installation paths differ by platform: Homebrew cask on macOS, yay for the Arch package, and downloads for Windows and other Linux distributions (Nix, AppImage and others). Building from source is a separate path documented in Getting started. After launch, you scan a QR code from WhatsApp's Linked devices screen, or enter an eight-character code, to link your phone.

Constraints to weigh

ZapFast is unofficial and not affiliated with WhatsApp or Meta; the README warns that using an unofficial client may violate WhatsApp's terms of service, so choose it deliberately rather than assuming account-level support. The project is MIT-licensed []. Desktop notifications still depend on OS permissions and presentation. Features are not the full WhatsApp feature set; the "What is ZapFast?" page is the place to check what is and is not implemented before switching.

HotRepo's take

The repository was recorded on GitHub's monthly Rust board on 2026-10-29 at +1,385 stars, best #10 that day. That is one dated observation, not evidence of a trend; the project was created on 2026-08-29, so it is very young. Treat the benchmark and feature coverage as author-reported and verify them against your own setup.