OneSignal - Customer engagement platform used by over 1 million developers and marketers; the fastest and most reliable way to send mobile and web push notifications, in-app messages, emails, and SMS.
MySQL - The world's most popular open source database
Truepush - Unleash limitless possibilities with Truepush and save up to $600 monthly. Free up to 10K Subscribers on all features.
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
PushCrew - Push Notifications for Websites
SQLite - SQLite Home Page