Datomic - The fully transactional, cloud-ready, distributed database
Notix.co - NOTIX is an audience re-engagement service based on web and in-app push notifications that work for both desktop and mobile devices.
Datahike - A durable datalog database adaptable for distribution.
Airship - Mobile marketing solutions across all major mobile platforms.
Valentina Server - Valentina Server is 3 in 1: Valentina DB Server / SQLite Server / Report Server
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.