Introduction to the Position

The Security Engineering team is responsible for designing and implementing the security measures that protect MX's digital assets and infrastructure. The team partners closely with development and operations teams to embed secure coding practices, identify vulnerabilities across the software lifecycle, and keep sensitive information confidential and intact. Its work spans application security, infrastructure and cloud security, threat modeling, incident response, compliance, and security automation.

This role exists to bring senior, hands-on security expertise to complex problems where the right approach is not yet defined. As a Senior Security Engineer, you will determine methods and procedures for new security initiatives, resolve complex issues that require in-depth evaluation, and may coordinate the work of other engineers as a team lead. You will be a go-to expert within the company, someone that peers and senior leaders rely on for advice and for key security decisions.

Your impact on MX will be measurable: faster vulnerability remediation, stronger incident response, reduced risk across our applications and infrastructure, and a clearer path to meeting industry regulations and standards such as SOC 2 and PCI, as well as contractual security requirements.

Job Responsibilities

• Own and execute application security initiatives, including identifying vulnerabilities and promoting secure coding practices throughout the development lifecycle, to reduce risk in MX software.
• Design and implement security controls for networks, servers, and cloud environments to protect against unauthorized access and data breaches.
• Lead threat modeling and risk assessments of the organization's assets, and use the results to prioritize security investments.
• Develop and execute incident response plans, including detection, containment, and recovery, and drive complex incidents through resolution.
• Provide technical expertise on regulations, standards (e.g., SOC 2, PCI), and contractual requirements, and partner with compliance and governance stakeholders to deliver audit-ready controls.
• Build and maintain security tooling and automation integrated into development and operational workflows to strengthen security and streamline processes.
• Partner with development and operations teams, and network with key contacts outside the security function, to deliver security solutions that fit how those teams work.
• Promote a culture of security by educating employees on security best practices and emerging threats, with a focus on secure code training.
• Track and improve security outcomes, such as vulnerability remediation time, incident response times, patch coverage, and the effectiveness of security controls, and translate them into business impact.
• Mentor other security engineers and coordinate team activities on new assignments as a team lead.

Basic Qualifications (Must-Have)

• Bachelor's degree in Computer Science, Information Security, or a related field (or equivalent practical experience).
• 8+ years of related security engineering experience with a Bachelor's degree; or 6+ years with a Master's degree; or 3+ years with a PhD; or equivalent experience.
• Demonstrated experience in application security and/or infrastructure security, including securing networks, servers, or cloud environments.
• Demonstrated experience performing threat modeling and risk assessments and using the results to prioritize security work.
• Experience supporting compliance with industry standards such as SOC 2 or PCI.

Preferred Qualifications

• Master's degree or PhD in Computer Science, Information Security, or a related field.
• Experience leading or coordinating security incident response from detection through recovery.
• Experience integrating security tools and automation into development and operational workflows.
• Experience designing or delivering secure code training or other security awareness programs.
• Experience in a regulated, fintech, or SaaS environment, and a track record of mentoring engineers or acting as a team lead.