This package defines a new alert style (toast) for alert.el using Windows 10 toast notifications. It works with native Windows 10 Emacs versions and with Emacs run under Windows Subsystem for Linux (WSL) or under Cygwin. These notifications are limited to a single-line title and four lines of text. Longer text can be passed but it will be truncated by Windows 10.

The package is available on MELPA and can be installed with Emacs package managers.

Ensure that package.el is initialized and uses MELPA as a source of packages:

(require 'package)
(add-to-list 'package-archives '("melpa" . "https://melpa.org/packages/") t)
(package-initialize)

Install and load alert-toast with:

(package-install 'alert-toast)
(require 'alert-toast)
;; (setq alert-default-style 'toast)

You can install alert-toast and set it as the default style with:

(use-package alert
  :commands (alert)
  :config (setq alert-default-style 'toast))
  
(use-package alert-toast
  :after alert)

This package defines a new alert style ('toast), so use it the same way you would use any other style. To set it as the default alert style, put the following in your init file:

(setq alert-default-style 'toast)

or to use it with mu4e-alert, you should put:

(mu4e-alert-set-default-style 'toast)

Looking at Windows.UI.Notifications API, toast notifications seem to support 2 priority levels: High and Default. Mapping between alert.el priorities and these levels is defined by alert-toast-priorities. According to API docs, high priority toast may wake up the screen if it's in standby mode. I haven't actually noticed any difference between default and high priority toasts.

Icons located on network shares are not supported. This includes icons on the WSL virtual drive, therefore for Emacs running under WSL the default Emacs icon is copied to C:\Users\<user>\AppData\Local\Emacs-Toast\Emacs.png. PNG version is used because toast notifications render SVG graphics as tiny and put them in top left corner of the notification. A different default icon can be set be changing alert-toast-default-icon.

Under WSL or Cygwin, a path to a custom icon should be given as a WSL/Cygwin path (/mnt/c/... or /cygdrive/c/...) instead of a Windows path (C:\\...).

The global alert.el variable controlling how long a notification persists is alert-fade-time. For this package, this is the number of seconds a toast persists in the action center before being removed for good. This is not the number of seconds the toast is visible before sliding out of sight. The amount of time the toast is visible is controlled by :long property of :data plist, which can either be t or nil (default). The default short notification lasts for several seconds, a long one last for around ~20 s:

(alert-toast-notify '(:title "Tytuł" :message "Zaźółć gęślą jaźń" :data (:long t)))

alert.el allows passing alert provider-specific options in the :data property. alert-toast.el expects the value of :data to be another plist with properties:

• :audio, one of symbols found in alert-toast--sounds or alert-toast--looping-sounds. Choosing one of the latter implies a long, looping notification.
• :long, t or nil. See Fade time.
• :loop, t or nil. Loop the notification sound.
• :silent, t or nil. Disable sound.

For example:

(alert-toast-notify '(:title "Tytuł" :message "Zaźółć gęślą jaźń" :data (:audio alarm5)))

alert-toast.el also supports shoulder taps aka My People notifications. To use it, provide email of the contact as the :shoulder-person property of the :data plist in mailto:<email> format and an address (local or http) of a GIF or PNG image as :shoulder-payload property. If the file is local and you're using Cygwin or WSL, then convert the path to native Windows path with (alert-toast--icon-path path). The contact with the provided email address needs to be pinned to the taskbar beforehand, otherwise you'll get a standard toast notification.

For example:

(alert-toast-notify '(:title "Fallback title" :message "Fallback body" :data (:shoulder-person "mailto:[email protected]" :shoulder-payload "https://docs.microsoft.com/windows/uwp/contacts-and-calendar/images/shoulder-tap-static-payload.png")))

Note: Shoulder taps are known to be flaky.

There is an issue in WSL where wslhost.exe dies or never starts properly for no discernible reason, which prevents accessing Windows partitions and executables . If this happens then you should see a message that powershell.exe cannot be found. This will prevent this package from working. The only known workaround is to call wsl --shutdown and start WSL again.

erc-burnt-toast also implements toast notifications but in the context of the Emacs IRC client. It uses an external PowerShell module burnt-toast.

alert.el bundles toaster style which also provides toast notifications but requires an external C# utility.

Windows builds of Emacs include w32-notification-notify function which shows a tray icon with a tooltip as a notification.