A monitoring tool, a Docker image updater program, home-automation software, a task list manager, and backup software all share a common requirement: They need a way to send notifications to keep you informed when specific events occur. There are countless ways to send notifications, including emails, instant messages, and push notifications.

In this article, I'll explore ntfy [1] (pronounced "notify"), an open source project that receives alerts via HTTP through a REST API and converts them into push notifications for a smartphone app or a web browser on your desktop. Thanks to this API and its command-line interface, you can even enable your own shell scripts to send push notifications.

Ntfy uses an HTTP publish/subscribe pattern. A sender publishes notifications on a specific topic, defined by the URL segment following the domain, by sending data to a URL via an HTTP POST or PUT request. A receiver subscribes to this topic, which means that ntfy sends the data to the receiver each time a sender publishes a notification on the topic.

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