draw.io - Online diagramming application
Google App Engine - A powerful platform to build web and mobile apps that scale automatically.
UMLGraph - UMLGraph is a professional automated drawing tool that allows the designers the declarative specification and drawing of UML class and sequence diagram.
Dokku - Docker powered mini-Heroku in around 100 lines of Bash
yEd - yEd is a free desktop application to quickly create, import, edit, and automatically arrange diagrams. It runs on Windows, Mac OS X, and Unix/Linux.
Google Cloud Functions - A serverless platform for building event-based microservices.