LockIME
A macOS menu-bar app that keeps a chosen keyboard input source locked, re-applying it whenever it drifts, with separate rules per app, per website, or a global default.
LockIME is a macOS menu-bar app that locks the active keyboard input source. Whenever the user, or another app, switches away from the locked source, LockIME immediately switches back, and this can apply globally, per frontmost application, or, in an enhanced mode, per browser URL matched by domain, subdomain, exact address, or keyword.
Rules can either lock an input source, reapplying it whenever it drifts, or simply switch to it once when an app or page gains focus and then leave the user free to change it. It also detects when another program keeps reasserting its own input source, such as a game with built-in input-method handling, and briefly stands down instead of fighting that program indefinitely, logging the conflict so the user can set a lasting exception. Bare executables launched outside an app bundle, such as a Java process started by a third-party launcher, can also get their own rules.
It requires macOS 14 or later, is written in SwiftUI, and updates itself through Sparkle.