“Progress lives from the exchange of knowledge” was the slogan of this year’s EntwicklerCamp for developers, which took place from 25 to 27 March 2019 in Gelsenkirchen. We took part and presented our “Domino app server coexistence with Microsoft o365” to an interested audience of experts. Our presentation dealt with the necessary aspects of securely connecting and understanding these two worlds. The focus was on technical details of Azure-AD, AD, ADFS, SSO, idP, LDAP-Auth, OAuth, Outlook add-ins and of course Domino. Using a live environment we were able to show how the building blocks work together. And not only that – we were able to demonstrate the numerous advantages of coexistence and inspire visitors with this innovative topic.