Platform Security Engineer in London

ION Markets Information Security Team is looking to hire a Platform Security Engineer that supports the division’s security strategy through definition and implementation of security controls across our platforms, infrastructure, and operational workflows. The role spans security architecture, engineering, and operations with a strong focus on automation, detection, and secure‑by‑design principles. Additionally, you will participate in threat detection, incident response, and vulnerability management remediation.

You will serve as an operational responder, working closely with Product, infrastructure, and Security Operations teams. The ideal candidate is a hard‑working, dedicated, and motivated individual with excellent communication skills and a strong technical background seeking career progression within a dedicated security team.

• Serve as a senior incident responder, addressing emerging threats across the environment.
• Collaborate with infrastructure, network, and cross‑functional teams to contain, investigate, and remediate security incidents.
• Conduct root cause analysis and participate in forensic investigations as needed.
• Enhance system visibility by expanding logging coverage and implementing additional monitoring capabilities.
• Maintain, update, and regularly test incident response runbooks, containment strategies, and escalation protocols.
• Lead the end‑to‑end vulnerability management process for ION Markets systems, from identification to remediation.
• Provide support for security architecture reviews of developed systems to ensure alignment with best practices.
• Stay up to date with the latest security threats, news, intelligence, tactics, techniques, and vulnerabilities; conduct research and analysis to assess potential impact and exposure.
• Perform proactive threat hunting activities, and manage the triage, investigation, and escalation of security alerts.
• Develop standard operating procedures for operations and architecture activities.

• Degree, diploma, or certifications in a technology‑related field and/or relevant working experience; highly desired certifications include Pen Test+, Security+, OSCP, CCSP, CEH, GCIH, GMON.
• 7+ years’ experience in Information Security or Security Architecture roles.
• Fundamental programming/scripting capabilities (e.g., Python, PowerShell, Bash).
• In‑depth understanding of operating systems (Windows/Linux).
• Team player with the ability to work independently and unsupervised.
• Ability to own delegated tasks and see them through to completion.
• Ability to manage time and prioritize work to maximize productivity.
• Excellent written and verbal communication skills.
• Exceptional attention to detail and quality.
• Excellent problem‑solving techniques and troubleshooting skills.
• Endpoint security concepts, controls, and best practices for servers (Windows and Linux).
• General IT networking concepts, protocols, standards, and network security concepts, controls, and best practices.
• Cryptography fundamentals and data security controls and best practices.
• Forensic investigation techniques.
• Prior experience deploying, configuring, managing, and/or operating security technologies such as endpoint security (AV/EPP/EDR), SIEM, DLP, SWG, CASB, UEBA, IDS, IPS, firewalls, IAM/PIM/PAM, vulnerability management, MDM, etc.

We’re a diverse group of visionary innovators who provide trading and workflow automation software, high‑value analytics, and strategic consulting to corporations, central banks, financial institutions, and governments. Founded in 1999, we’ve achieved tremendous growth by bringing together some of the best and most successful financial technology companies in the world. ION is a rapidly expanding and dynamic group with 13,000 employees and offices in more than 40 cities worldwide.

ION is committed to maintaining a supportive and inclusive environment for people with diverse backgrounds and experiences. We respect the varied identities, abilities, cultures, and traditions of the individuals who comprise our organization and recognize the value that different backgrounds and points of view bring to our business.

ION adheres to an equal employment opportunity policy that prohibits discriminatory practices or harassment against applicants or employees based on any legally impermissible factor.