Ntfy

ntfy, pronounced notify, is a simple HTTP-based publish-subscribe notification service. It removes the ceremony around alerting, since there is no account to create and no fee to pay, and a cron job or a backup script can push a message to your phone with a single PUT or POST.

The server is written in Go and keeps a persistent message cache in SQLite, so subscribers that were offline still receive what they missed. Delivery reaches Android and iOS through Firebase Cloud Messaging, browsers through web push, and the bundled React web app through a live subscription. Messages can also arrive by email through a built-in SMTP listener.

The pieces that matter in daily use are these.

• Script friendly publishing: any tool that speaks HTTP can send a notification, curl included.
• Topics instead of accounts: subscribers pick a topic name and start receiving, with no registration step.
• Official mobile apps: the Android and iOS clients are open source and published on Google Play, F-Droid and the App Store.
• Message templating: Go text templates with Sprig functions shape incoming payloads into readable alerts.
• Tags and sounds: notifications carry emoji tags and notification sounds, so alerts stay distinguishable at a glance.

A free public instance is run by the maintainer, with paid plans for people who would rather not self-host and want to support development. The whole server is dual licensed under Apache 2.0 and GPLv2, ships as a single Go binary, and comes with its own command line client for publishing and subscribing.