Senior Information Security Engineer

Who we are

Optiver is a global market maker founded in Amsterdam, with offices in London, Chicago, Austin, New York, Sydney, Shanghai, Hong Kong, Singapore, Taipei and Mumbai. Established in 1986, today we are a leading liquidity provider, with close to 2,000 employees in offices around the world, united in our commitment to improve the market through competitive pricing, execution and risk management. By providing liquidity on multiple exchanges across the world in various financial instruments we participate in the safeguarding of healthy and efficient markets. We provide liquidity to financial markets using our own capital, at our own risk, trading a wide range of products: listed derivatives, cash equities, ETFs, bonds and foreign currencies.

What you’ll do

We are seeking a motivated, hands-on Senior Information Security Engineer to join our security team. In this role, you will help protect, monitor, and continuously improve the security of our global systems including cloud (AWS and M365) and on-premises infrastructure. You’ll play a central part in risk mitigation, incident response, automation of security operations, and embedding security best practices across our organisation. An engineering mindset, attention to detail, and a preference for pragmatic solutions are essential to keeping our systems operating.

Main responsibilities include

• Monitor daily security operations, identify threats, investigate alerts, and respond to incidents across cloud and on-prem environments.
• Strengthen Microsoft 365 and Entra ID security through Conditional Access, MFA, PIM, Defender for Endpoint/Identity/O365, and tenant configuration hardening.
• Build and maintain security automation using Python and PowerShell, with a strong focus on reducing manual processes and improving detection and response.
• Integrate systems using APIs (Graph API, REST, etc) to enhance security workflows.
• Perform vulnerability assessments, review system configurations, and develop practical mitigation strategies.
• Contribute to incident response activities including investigation, containment, communication, and remediation.
• Work closely with engineering, technology, and business teams to embed security best practices.

Who you are

Optiver needs our next Information Security Engineer to have:

• At least 5 years experience in an information security or technical engineering role.
• Ability to apply analytical thinking to technical problems within a fast-moving environment.
• Comfortable with both Windows and Linux environments; familiarity with common security technologies (firewalls, endpoint protection, log management, vulnerability scanning, network security).
• Solid scripting skills in PowerShell and/or Python
• Knowledge of secure Identity Management, authentication principles, and modern access control patterns.
• Experience using security tooling such as EDR, SIE