Hey Product Hunt 👋 A normal hour of my work touches six apps. Editor, terminal, browser, API client, and two different chat apps because that's the world we live in. I'd be in the middle of a thought, need the one in the browser, and lose a second and a half hunting for it - every single time, a hundred times a day. Cmd-Tab doesn't help once you're past four apps; the order changes depending on where you just were, so the thing you want is never in the same place twice. I wanted one key per app. Same key, same app, every time, no matter what I was looking at. So I built it. ⌨️ **Hyper key** — hold Caps Lock and it stamps a modifier set onto whatever you press next. That's the part that makes one-key-per-app possible: a fifth modifier nothing else has claimed, so ⇪C is the editor and ⇪B is the browser and nothing in any app ever argues with you about it. 🎯 **Instant app switching** — launch it if it's closed, focus it if it's open, and *toggle* it if you want: the same key brings it up and puts it away again. Plus cycling between one app's windows, and arranging the front window where you want it. 🗂️ **Leader menus** — for when you've got more apps than comfortable letters. One combination opens a cheatsheet on screen, then one bare key picks from it. Twelve destinations under one combo, with only the first key to remember. ✍️ **Snippets & 🔀 Flows** — because once the switching stopped costing me anything, the next thing was what I was doing *after* I arrived. Snippets with 32 dynamic variables, and a node graph for one keypress doing four steps in order with a condition in the middle. The detail I'd most want someone to tell me about: **anything automating your typing has to be careful, so Lumi never deletes on trust.** I type in Vietnamese, and a Vietnamese IME rewrites characters *after* the keyboard tap has already seen them — so what Lumi watched you type isn't reliably what your app received. Every match is treated as a suspicion. Before deleting anything, it reads the text in front of your caret back through the Accessibility API and checks. If it doesn't line up, it skips, silently. A missed expansion costs you one retyped word. Eating the wrong characters costs you the tool forever. I use it for every keystroke of my day and I'd love to hear what you'd bind to it - genuinely, that's how I pick what to build next. What's the shortcut your Mac has never had?

Lumi

Light up your keyboard.

Light up your keyboard.