Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
jsonbox.io - A free HTTP based JSON Storage.
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.
Refi App - An open-source GUI tool to make interacting with Firestore less painful
Parse - Build applications faster with object and file storage, user authentication, push notifications, dashboard and more out of the box.
How to GraphQL - Open-source tutorial website to learn GraphQL development