Parse - Build applications faster with object and file storage, user authentication, push notifications, dashboard and more out of the box.
AWS Mobile Services - Storage, Analytics, Push Notif. & SMS Delivery SDKs
MongoDB Stitch - The serverless platform from MongoDB
Azure Mobile Apps - Build engaging cross-platform and native apps for iOS, Android, Windows or Mac with Azure's Mobile App Service.
Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.