ntfy
ntfy.sh | Send push notification…ur phone via PUT/POST
ntfy (pronounced notify) is a simple HTTP-based pub-sub notification service. It allows you to send notifications to your phone or desktop via scripts from any computer, and/or using a REST API. It's infinitely flexible, and 100% free software.
UnifiedPush というプッシュ通知送受信規格を利用したサービス
……と理解しているzatsma.icon