Ntfy – open-source Push to Mobile
Summary
ntfy is an open-source, HTTP-based pub-sub notification service that lets you publish and subscribe to topics to push notifications to mobile and desktop via scripts or REST API. It supports attachments, priorities, action buttons, and a web UI, with Pro and self-hosted options, and broad integrations; it's dual-licensed under Apache 2.0 and GPLv2, with an active community.