I can't even work on Mac without it. It let's you do stuff like "alt+spc a b" (apps -> browser) or "alt+spc m j/k" (media -> vol up/down), or edit just about any text of any app in your editor (Emacs atm) - with all the tools you have there - spellchecking, thesaurus, translation, LLMs, etc.

You can plug it to your favorite WM (I'm currently using Yabai) and do tons of other interesting things. Because it's all written in Fennel, one can develop things in a tight feedback loop with a connected REPL - e.g., I can ask Claude to inspect things in the running Slack app or Firefox and make interesting automations - all without ever leaving my editor.

- Vim mode everywhere in macOS: https://github.com/dbalatero/VimMode.spoon

- Modifier keys + click/drag to resize or move windows: https://github.com/dbalatero/SkyRocket.spoon

- Show an overlay helper of all your keybinds when you hold modifier keys down: https://github.com/dbalatero/HyperKey.spoon

And my huge pile of random scripts/configs: https://github.com/dbalatero/nixpkgs/tree/main/home/modules/...

  - Dumping all open Safari tabs to an Obsidian doc
  - Adding 'hyper' (Ctrl-Opt-Cmd) keybinds to pop a new window for:
    - Safari
    - Finder
    - Terminal / Ghostty
    - VS Code
    - Notes
    - Editing Hammerspoon/AeroSpace/Sketchybar config
    - Reloading Hammerspoon config
    - Reloading Sketchybar
    - Quitting all Dock apps except Finder
    - Screen lock
    - System sleep
    - Opening front Finder folder in VS Code
    - Opening front Safari URL on Archive.today
    - Showing front Safari window tab count
    - Showing front app bundle ID
    - Posting notification about current Music track
    - Controlling my Logi Litra light (various color temps/brightnesses)
    - Starting/stopping a client work timer
  - Tying it to AeroSpace for:
    - Pushing a window to another monitor
    - Performing a two-up window layout
    - Swapping those two windows
    - Closing all other workspace windows
    - Gathering all windows to first workspace
  - Ensuring some background apps stay running if they crash
  - Prompting to unmount disk images if trashed
  - Binding into Skim to jump to specific sections of spec PDFs using terse Markdown URLs

     -- resize based on ratios
    function ratioResize(xr, yr, wr, hr)
      return function ()
        local win = hs.window.focusedWindow()
        win:moveToUnit({x=xr,y=yr,w=wr,h=hr})
      end
    end

    -- 4 corners, different sizes
    hs.hotkey.bind({"cmd", "ctrl"}, "w", ratioResize(0,     0, 2/5, 2/3))
    hs.hotkey.bind({"cmd", "ctrl"}, "e", ratioResize(2/5,   0, 3/5, 2/3))
    hs.hotkey.bind({"cmd", "ctrl"}, "s", ratioResize(0,   2/3, 2/5, 1/3))
    hs.hotkey.bind({"cmd", "ctrl"}, "d", ratioResize(2/5, 2/3, 3/5, 1/3))

    -- send to next screen
    hs.hotkey.bind({"cmd", "ctrl"}, ";", function()
      local win = hs.window.focusedWindow()
      local screen = win:screen()
      local next_screen = screen:next()

      win:moveToScreen(next_screen)
    end)

    -- Hide Zoom's "share" windows so it doesn't come back on ESC keypress
    local zoomWindow = nil
    local originalFrame = nil
    
    hs.hotkey.bind({"cmd", "ctrl", "alt"}, "H", function()
      print("> trying to hide zoom")
      if not zoomWindow then
        print(">  looking for window")
        zoomWindow = hs.window.find("zoom share statusbar window")
      end
    
      if zoomWindow then
        print(">  found window")
        if originalFrame then
          print(">    restoring")
          zoomWindow:setFrame(originalFrame)
          originalFrame = nil
          zoomWindow = nil
        else
          print(">    hiding")
          originalFrame = zoomWindow:frame()
          local screen = zoomWindow:screen()
          local frame = zoomWindow:frame()
          frame.x = screen:frame().w + 99000
          frame.y = screen:frame().h + 99000
          zoomWindow:setFrame(frame)
        end
      else
        print(">  window not found")
      end
    end)

    hs.hotkey.bind({"ctrl"}, "D", function()
      hs.grid.show()
    end)

(1) ctrl-d to see the grid, (2) type the letter where you want the top left corner of your window to be, (3) type the letter where you want the bottom right corner to be

window resized

  local usbWatcher = hs.usb.watcher.new(function(device)
    if device.productName == "EMEET SmartCam C960" then
      if device.eventType == "added" then
        hs.execute("networksetup -setairportpower en0 off")
        hs.notify.new({title="Wi-Fi", informativeText="Disabled (USB device connected)"}):send()
      elseif device.eventType == "removed" then
        hs.execute("networksetup -setairportpower en0 on")
        hs.notify.new({title="Wi-Fi", informativeText="Re-enabled (USB device removed)"}):send()
      end
    end
  end)
  usbWatcher:start()

Yabai supports this perfectly (especially combined with instant, animation-free space switching) but it requires disabling system integrity protection--which is a non-starter on a work computer.

Aerospace solves it with their own spaces implementation.

I was able to put together a hammerspoon script that does the job decently enough for my purposes: https://gist.github.com/kcrwfrd/6f3dcaec0e08e0e77b2884588a34...

Then I just figured out that I have Hammerspoon, it can control windows -> recreate one exactly how I like it. Been using it for a year now and it's 99% perfect. Some specific applications (coughFirefoxcough) sometimes get into a weird state that doesn't work, but I can live with that.

It can also pop all windows to a specific layout with a single shortcut by combining the active wifi + monitor setup to detect if I'm at home, at work, or working at home.

    local appHotkeys = {}

    local function remapAppHotkey(appName, fromMods, fromKey, toMods, toKey, delay)
        if not appHotkeys[appName] then
            appHotkeys[appName] = {}
        end
        local hotkey = hs.hotkey.new(fromMods, fromKey, function()
            hs.eventtap.keyStroke(toMods, toKey, delay or 0)
        end)
        table.insert(appHotkeys[appName], hotkey)
    end
    
    local appWatcher = hs.application.watcher.new(function(appName, eventType)
        local hotkeys = appHotkeys[appName]
        if not hotkeys then return end
        for _, hotkey in ipairs(hotkeys) do
            if eventType == hs.application.watcher.activated then
                hotkey:enable()
            elseif eventType == hs.application.watcher.deactivated then
                hotkey:disable()
            end
        end
    end)
    
    appWatcher:start()

    -- Remap app hotkeys
    remapAppHotkey("Finder", { "cmd" }, "q", { "cmd" }, "w", 0.5)
    ... etc ...

otherwise I'm slowly working on a Spoon that figures out if there is an active meeting in Zoom, Teams, Huddle, Google Meet and will allow for muting, video enable/disable and screen sharing etc

It's lua, so you can get creative with https://fennel-lang.org/

Hammerspoon seems like a superset and it’s probably better to just have one, instead of two tools warring about who gets the keypresses?

It's fun to combine with qmk [0], which gives you a bunch more options for hotkeys on your keyboard via layers. I've ended up with a layer where half the keyboard is Hammerspoon shortcuts directly to apps (e.g. go to Slack, to Chrome, etc.) and half of it is in-app shortcuts (like putting cmd-number on the home row, for directly addressing chrome tabs).

Between this and one of the tiling window manager-adjacent tools (I use Sizeup), I can do all my OS-level navigation directly. "Oh I want to go to Slack and go to this DM" is a few keystrokes away, and not dependent on what else I was doing.

[0] https://qmk.fm/

Can't live without AutoHotkey on Windows.

Thanks to everyone who contributed to both!

Some previous discussion:

2021 https://news.ycombinator.com/item?id=29533495

2019 https://news.ycombinator.com/item?id=21801178

KeyboardMaestro

Automator and AppleScript

Raycast