Gõ Nhanh
Open source
Gõ Nhanh is a free, fast, and stable Vietnamese input method for macOS. Install it and go: no ads, no tracking, no account, fully open source.
The idea
Typing Vietnamese should be invisible. The best input method is the one you forget is there: quick to learn, predictable under pressure, and out of your way. Gõ Nhanh aims for exactly that: correctness and speed without the bloat that creeps into tools like this.
Open by default
The whole thing is open source because an input method sees everything you type; trust has to be inspectable, not promised. Contributions and issues are welcome.