Senior Microsoft 365 Infrastructure/Platform Engineer

We are looking for a proactive and experienced Senior Microsoft 365 Infrastructure/Platform Engineer to join our team and help operate, maintain, and continuously improve our Microsoft 365 platform in a large-scale enterprise environment. Our client is a leading European online car marketplace, connecting car buyers and sellers across the continent. The platform serves over 30 million monthly users and operates across 18 countries, making it one of the largest and most trusted digital marketplaces for vehicles in Europe. Responsibilities: Operate, administer, and continuously improve Microsoft 365 enterprise services. Manage and optimize Microsoft 365 components, including Exchange Online, Microsoft Teams, SharePoint Online, OneDrive for Business, and Microsoft Entra ID. Automate administrative tasks and operational processes using PowerShell and Microsoft Graph. Plan and execute Microsoft 365 tenant migrations, consolidations, and decommissioning projects. Provide 3rd Level Support by analyzing and resolving complex Microsoft 365 platform issues. Act as a technical point of contact for the User Services team, providing guidance and troubleshooting support. Drive Microsoft 365 and Entra ID cleanup initiatives related to post-merger integration activities. Reduce operational backlog by identifying recurring issues and implementing sustainable improvements through automation, documentation, and process optimization. Create and maintain technical documentation, operational procedures, and platform standards. Collaborate with cross-functional teams and stakeholders to ensure reliable and scalable Microsoft 365 services. Requirements: 5+ years of professional experience as a Microsoft 365 Engineer. Proven experience administering and operating Microsoft 365 in large enterprise environments supporting thousands of users. Strong expertise with: Microsoft 365, Exchange Online, Microsoft Teams, SharePoint Online, OneDrive for Business, Microsoft Entra ID (including Enterprise Applications and App Registrations) Strong PowerShell scripting skills for automation. Hands-on experience with hybrid environments, including Active Directory and Microsoft Entra Connect. Experience planning and delivering Microsoft 365 migrations, tenant consolidations, and tenant decommissioning projects. Experience with M&A, carve-out, or post-merger integration initiatives. Strong analytical and problem-solving skills with a structured, solution-oriented approach. Excellent communication skills and the ability to explain technical concepts to non-technical stakeholders. Upper-Intermediate level of English Nice to Have: Experience with Microsoft Graph API. German language skills. Experience driving platform modernization and technical debt reduction initiatives. Experience building scalable automation and operational improvements. Ability to take ownership, proactively identify improvement opportunities, and drive initiatives independently. Experience working in complex enterprise environments with multiple stakeholders. We offer*: Flexible working format - remote, office-based or flexible A competitive salary and good compensation package Personalized career growth Professional development tools (mentorship program, tech talks and trainings, centers of excellence, and more) Active tech communities with regular knowledge sharing Education reimbursement Memorable anniversary presents Corporate events and team buildings Other location-specific benefits *not applicable for freelancers