Growl

Growl was a global notification system for macOS that predated the built-in system notifications feature. This allowed any application to issue notifications in several formats (the notifier windows themselves were customizable, and you got to pick from several kinds in the default install):

Unlike other alternatives such as LanOSD, was licensed in the public domain and had Perl and Python bindings (it was a framework, so any language with Objective-C bindings could interop with it, and it shipped with a small set of Xcode samples).

Resources:

Category Link Notes
Analogues Window.Growl JavaScript snippet that displays Growl-like in-page notifications.
Snarl for Windows. I find the name oddly appropriate to the platform.
Mumbles a notification system for GNOME that uses my Python library
Windows port somewhat official.
Extensions Yapper A XMPP bridge.
Prowl A Growl relay for the iPhone
Libraries Nathan's port to Perl, Referenced here for ease of tracking.
My DBUS bridge Experimental, not really maintained.
notification relay to re-send notifications to machines behind a NAT firewall (1-to-n)
My protocol implementation In Python, not really maintained anymore but working.
My other implementation In PHP, of all things. Not really maintained as well, but still being used by a lot of folk.
Odds and Ends My UDP protocol diagrams in .sxd format:

Scripts:

Melo’s x-notify shell script:

#!/bin/sh
#
# Runs script, and prints a notification with growl when it finishes
#
$*
growlnotify -m "Script '$*' completed" -s "Background script notification" &