Specialist Microsoft 365 (Exchange Online - The Hague / Hybrid - 32-40h

About this position

Are you someone who understands the Microsoft ecosystem inside and out and enjoys solving complex technical challenges? Do you get energized by troubleshooting issues in a large-scale enterprise environment, with a particular passion for email platforms and mail flow?

As a Microsoft 365 Specialist, you will play a key role in maintaining and further developing TNO's Microsoft 365 environment. Within our team, your primary focus will be Exchange Online, email delivery, email security, and automation. At the same time, you will have the opportunity to broaden your expertise across the wider Microsoft stack, including Teams, SharePoint, Intune, and Entra ID.

You will join a team that manages and continuously improves a large and complex Microsoft 365 environment that supports thousands of users across TNO.

What will be your role?

You will strengthen our Microsoft 365 team with a strong focus on Exchange Online and email-related technologies. Together with our current email specialist, you will act as the go-to expert for email services, supporting business-critical applications and users across the organization.

Your responsibilities include:

• Managing and configuring Exchange Online in a large enterprise environment
• Diagnosing and resolving complex email delivery and mail flow issues
• Configuring and maintaining mailboxes, distribution groups, and Exchange policies
• Implementing and managing email security solutions through Microsoft Defender for Office 365
• Developing PowerShell scripts to automate operational tasks and improve efficiency
• Providing 3rd-line support for escalated incidents and service requests
• Collaborating with stakeholders across the organization on email-related solutions
• Contributing to knowledge sharing and continuous improvement within the team

The team

You will be part of a diverse and highly skilled Microsoft 365 team responsible for managing TNO's modern workplace and collaboration platforms. The team combines deep technical expertise with a strong focus on innovation, collaboration, and continuous learning.

Within the team, you will work closely with our current email specialist while also collaborating with colleagues responsible for Teams, SharePoint, Intune, identity management, and other Microsoft 365 services.

What we expect from you

You have hands-on experience with Exchange Online administration and enjoy diving deeper than standard configurations. You understand how email delivery works, can troubleshoot complex mail flow issues, and are eager to further develop your expertise across the wider Microsoft 365 landscape.

Most importantly, you are curious, proactive, and continuously looking to learn.

Must-haves

• Experience managing and configuring Exchange Online
• Knowledge of email delivery troubleshooting and mail flow, including message tracing, NDRs, connectors, and transport rules
• Experience with Microsoft Defender for Office 365, including anti-spam, anti-phishing, and threat protection policies
• Understanding of email security fundamentals, including SPF, DKIM, and DMARC
• Experience with PowerShell scripting and automation
• Affinity with 3rd-line support and complex troubleshooting
• Strong communication skills in both Dutch and English
• Strong learning capability and a proactive mindset

#LI-Hybrid
Nice-to-haves

• Experience working in Agile or Scrum teams
• Knowledge of Microsoft 365 Compliance and eDiscovery
• Experience with hybrid Exchange environments
• Relevant Microsoft certifications
• Experience with Azure DevOps
• Experience with Freshworks

What you'll get in return

TNO offers optional employee benefits, enabling you to tailor your benefits package to match your personal situation. You may also expect:

• An extremely professional, innovative working environment where colleagues are leading experts in their field.
• The opportunity to attend courses, workshops and conferences, and to receive training and coaching based on your needs.
• 33 days annual leave plus a flexible holiday that can be used on a cultural, religious, or otherwise important day of your choosing (on a full-time basis).
• An employer working towards a respectful, inclusive, and equitable work environment where every employee can flourish, with various initiatives such as Jong TNO, numerous expertise based guilds, Rainbow Community and Round Tables on diverse inclusion topics.
• We offer a comprehensive and flexible mobility plan that also includes full compensation for public transportation for commuting and business travel.
• Great social events with your team and other TNO colleagues. That’s how you will get to know a lot of people really quickly.
• Flexible working hours, the possibility to work parttime (32 or 36 hours) and the possibility of working from home.
• A good pension scheme.

Read more about tailoring your benefits package.

TNO as an employer

Our people are at the heart of TNO. Their curiosity, expertise and entrepreneurial mindset make it possible to deliver high-impact research and innovations that contribute to society’s sustainable wellbeing and prosperity. That is why we invest in an inspiring and inclusive working environment where colleagues can excel, have autonomy and continue to grow.

Your talent and ambition have every opportunity to flourish at TNO. You work with experts (both within and beyond TNO), have access to advanced technology and the freedom to explore, experiment and innovate. Our strength lies in independence, reliability and collaboration. We find each other in wonder and ingenuity. We are driven to push boundaries. By working with businesses and government, and by connecting different perspectives, we strengthen our innovative capability and create responsible, meaningful results.

At TNO, we believe this is our time to help society, government and business move forward faster. Together with driven colleagues, you turn knowledge into concrete innovations or ventures that truly make a difference by combining the power of science and entrepreneurship. And in doing so, you make your mark on our time.

The selection process

Please apply before the 25th of October, 2026. The selection process comprises two interview rounds. In a final meeting we will discuss the terms of employment and your tailored benefits package. We aim to finalize the entire process within four weeks.

As you will be working for clients in the domain of defence and security, a Certificate of No Objection issued by AIVD (the Dutch General Intelligence and Security Service) is mandatory. This means you will have to undergo a security screening. Read more about security screening.