Parse - Build applications faster with object and file storage, user authentication, push notifications, dashboard and more out of the box.
openDesktop.org - The website openDesktop.
Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
SourceForge - The Complete Open-Source and Business Software Platform.
AWS Amplify - JavaScript library for app development using cloud services
Freecode - Freecode (formerly known as Freshmeat) is one of the legit open source development platforms that will be the key for developers and programmers to have a streamlined process via having enhanced collaboration and coding leverages.