Job Description
We are seeking a highly experienced Senior System Administrator to support and evolve our hybrid on‑premises and cloud infrastructure in a Geneva‑based, international environment. This role requires strong expertise in Microsoft technologies, Azure, identity and security services, and virtualization, with a high standard of reliability and professionalism.
The position plays a critical role in ensuring availability, security, and compliance of core IT services supporting business‑critical operations.
Key Responsibilities
- Design, implement, and maintain Windows Server environments (on‑premises and cloud)
- Administer and optimize Microsoft Azure infrastructure and services
- Manage and support Microsoft 365 / Office 365, including Exchange Online and collaboration services
- Administer Microsoft Entra ID (Azure AD), including hybrid identity, synchronization, conditional access, and authentication policies
- Manage Active Directory, ADFS, DNS, and core identity services
- Operate and maintain VMware virtualization platforms
- Administer Microsoft Exchange environments (on‑premises, hybrid, and/or cloud)
- Manage Public Key Infrastructure (PKI), including certificate authorities and trust models
- Ensure certificate lifecycle management (TLS/SSL, authentication, encryption) across servers, applications, and services
- Ensure high availability, backup, disaster recovery, monitoring, and capacity planning
- Troubleshoot complex infrastructure, identity, and authentication issues
- Apply security best practices in line with Swiss and international compliance requirements
- Participate in audits, risk assessments, and documentation efforts
- Collaborate closely with internal IT teams and international stakeholders
- Maintain clear technical documentation and operational procedures
- Provide technical leadership and mentoring to less experienced administrators
Required Technical Skills & Experience
- Several years of experience as a Senior System Administrator in an enterprise environment
- Strong hands-on expertise in:
- Microsoft Azure
- Microsoft Entra ID (Azure AD)
- Microsoft 365 / Office 365
- Windows Server
- VMware / Vsphere
- Active Directory & ADFS
- DNS, DHCP
- Microsoft Exchange
- PKI and certificate management
- Proven experience with hybrid (on‑premises and cloud) infrastructures
- Solid understanding of identity, authentication, encryption, and security principles
- Experience with PowerShell and automation is highly valued
Soft Skills & Personal Attributes
- Open-minded – comfortable working in a multicultural, international environment
- Reliable – trusted to operate and support critical systems
- Flexible – adaptable to changing priorities, projects, and operational needs
- Structured and methodical approach to problem-solving
- Strong communication skills in technical and business contexts
- Team player with a professional and service-oriented mindset
Languages
- English: professional working proficiency (required)
- French: working knowledge is a strong advantage
Nice to Have
- Microsoft / Azure certifications
- Experience in regulated environments (finance, trading, healthcare, international organizations)
- Familiarity with Swiss data protection and security standards
- Experience supporting international or multi-site infrastructures
