Git is a free and open source distributed version control system designed to handle everything from small to very large projects with speed and efficiency.
Jenkins is an open source automation server written in Java. Jenkins helps to automate the non-human part of the software development process, with continuous integration and facilitating technical aspects of continuous delivery. It is a server-based system that runs in servlet containers such as Apache Tomcat.
Mandrill is a scalable and affordable email infrastructure service, with all the marketing friendly analytics tools they come to expect from MailChimp.
Microsoft Office 365 provides web, desktop, and mobile apps for Outlook, Word, Excel, PowerPoint, OneNote, Publisher, Skype, OneDrive, Exchange Online, and more.
Microsoft Teams is a chat-based workspace in Office 365 which lets users collaborate on documents, make voice & video conference calls, view chat logs, and more.