When comparing Hammerspoon vs Spectacle, the Slant community recommends Spectacle for most people. In the question“What are the best power user tools for macOS?” Spectacle is ranked 33rd while Hammerspoon is ranked 37th. The most important reason people chose Spectacle is:
Spectacle is licensed under MIT with source code available on [GitHub](https://github.com/eczarny/spectacle).
Ranked in these QuestionsQuestion Ranking
Pro Deeply customizable
Hammerspoon's Lua scripting and broad API allows you to perform any action you can imagine on your mac. It hooks into many OS APIs directly and has some high-level APIs to manipulate things like Spotify or iTunes. See the full list here.
Pro Automate actions based on the operating system
Hammerspoon lets you hook into OS level events and trigger any action you can imagine. From setting up a simple keyboard shortcut to launching a complex workflow using multiple apps and scripts.
Pro Free and open source
Spectacle is licensed under MIT with source code available on GitHub.
Pro Low footprint
Spectacle only uses up 18-19 MB of RAM, which means there is not much overhead by using this app.
Pro Simple hotkeys
Spectacle offers easy-to-remember preset hotkeys.
All windows in Spectacle can be controlled with keyboard shortcuts, so no mouse is needed. This makes for a fast way to control windows.
Pro Great UX
Spectacle is easy to use and configure. It's plug and play.
Pro Multi-monitor support
Con Some knowledge of programming required
Hammerspoon is scripted in the Lua programming language, and some familiarity with programming in general will be needed to use it. Some plugins exist that can be used by adding some files to a specific folder, but this will not give the flexibility that is so key to Hammerspoon
Con Impossible to add new functions
While keyboard shortcuts can be changed for the available actions, there is no way to add custom actions which in turn limits the functionality of the app.
Con Limited window sizing capabilities
You can use 1/2 of the screen vertically and horizontally (divide into 4 parts). You can also use the screen in thirds too, but only the left and right third: you can't use the 1/3 in the center. There is no way to do a more granular distribution.
Con Not maintained
The software is free, but no longer seems to be maintained.
Con Breaks on macOS High Sierra / Chrome or Firefox
Doesn't support side by side windows.
Con Doesn't work with any Adobe products
There are some apps like Adobe Reader that do not work with Spectacle. Basically, any app with a heavily customized UI that breaks OS X accessibility will not work correctly under Spectacle.