Office Manager

Get to Know Us Horizon3 is a fast-growing cybersecurity company dedicated to the mission of enabling organizations to proactively find and fix and verify exploitable attack vectors before criminals exploit them. Our flagship product, the NodeZeroTM platform, delivers production-safe autonomous pentests and other key assessment operations that scale across the largest internal, external, cloud, and hybrid cloud environments. NodeZero has been adopted by organizations of all sizes, from small educational institutions to government agencies and Global 100 enterprises. It is used by ITOps/SecOps teams, consulting pentesters, and MSSPs and MSPs.  We are a fusion of former U.S. Special Operations cyber operators, startup engineers, and formerly frustrated cybersecurity practitioners. We're committed to helping solve our common security problems: ineffective security tools, false positives resulting in alert fatigue, blind spots, "checkbox” security culture, cybersecurity skills shortage, and the long lead time and expense of hiring outside consultants. Collectively, we are a team of learn it alls, committed to a culture of respect, collaboration, ownership, and results.   What You’ll Do We are seeking an ambitious and proactive Office Manager to join our team in Amsterdam. This is a dual-focus role. Approximately half of your time will be dedicated to owning the day-to-day operations of our Amsterdam and UK offices. The other half will be focused on executive support to our VP of EMEA, including diary management, travel coordination, and the logistics and planning of EMEA-wide events. You will be responsible for managing daily office operations, managing vendors, and creating an exceptional employee experience. You will be expected to be in the office typically 4–5 days per week. The nature of this role offers visibility from leaders across our growing EMEA organization and the chance to showcase ambition to executive leadership. Office Operations & Facilities (~50%) Own day-to-day office operations in our Amsterdam office, including supplies, mail, facilities management, and ensuring the space is always welcoming and fully operational Act as primary liaison with building management, contractors, and service providers Manage vendor relationships, contracts, and service quality for all office-related providers Prioritize the employee experience, ensuring the Amsterdam office reflects Horizon3's culture and is a place where employees feel energized, supported, and connected Remotely manage day-to-day operations of our UK office as it comes online, including: standing up vendor relationships, coordinating logistics, and serving as the operational point of contact for UK-based employees Executive & EMEA Support (~50%) Serve as the executive support partner for our VP of EMEA, managing complex scheduling, calendar prioritization, and travel coordination across the region Plan, coordinate, and execute EMEA-wide events, including team offsites, customer events, regional all-hands, and milestone celebrations, all while ensuring smooth end-to-end logistics (venues, travel, catering, activities, and budgets) Own logistics and scheduling for EMEA leadership meetings, QBRs, and cross-functional gatherings, anticipating needs and resolving conflicts proactively Manage vendor relationships for EMEA event services, including caterers, venues, and entertainment Track budgets and ensure events and travel are delivered on time, within scope, and aligned with company values What You'll Bring 2+ years of experience in office management, executive support, operations, or administrative roles, ideally in a fast-growing company Strong organizational skills with the ability to multitask and prioritize effectively across both executive support and office operations Excellent written and verbal communication skills in English required; Dutch proficiency is a plus Tech-savvy with proficiency in tools like Google Workspace, Slack, Zoom, and