restdb.io - restdb.io lets you create databases and REST APIs quickly. Development databases are free. Powerful web-based and mobile-friendly data management.
ifttt - IFTTT puts the internet to work for you. Create simple connections between the products you use every day.
Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
Zapier - Connect the apps you use everyday to automate your work and be more productive. 1000+ apps and easy integrations - get started in minutes.
RemoteStorage - An open protocol for per-user storage OWN YOUR DATA
n8n.io - Free and open fair-code licensed node based Workflow Automation Tool. Easily automate tasks across different services.