OpenPush

The OpenPush project aims to create a free and open source self-hosted replacement for Android Push Notifications usually sent through Google's proprietary Firebase Cloud Messaging platform. This started as a PrototypeFund project. Development is still ongoing.

Benefits

• Free Software. FCM is a proprietary service and the Firebase client libs are closed source. This makes projects including fcm libraries effectively non-free software which i.e. cannot be added to the FOSS F-Droid appstore.
• Self-hosted. When self-hosting a open source project, there's no dependency on an external service anymore.
• User is in control. A smartphone user can chose a pushserver instance, possibly self-hosted or hosted by a trusted entity. This instance's url is communicated to the webservice together with the app token to the push-notification producer. Push-notifications will only be sent to this server.