Security Engineer (AppSec / GRC / AI Security) in United Kingdom

This position is listed on behalf of a partner company, which manages all applications and next steps. Our partner is looking for a Security Engineer (AppSec / GRC / AI Security) based in United Kingdom. As a Security Engineer, you will take end-to-end ownership of security across a rapidly growing technology platform serving more than 50 million users worldwide. This hands-on role combines application security, vulnerability management, governance, risk, and compliance, with a growing focus on emerging AI security threats. You will work closely with engineering leadership and development teams to identify vulnerabilities, strengthen internal controls, and build robust security practices. As the sole dedicated Security Engineer, you will have significant autonomy to shape security strategy, prioritize risks, and drive remediation from discovery through resolution. You will also help protect AI-powered systems against evolving threats, including prompt injection, jailbreaks, and third-party provider vulnerabilities. This is an opportunity to make a direct impact in a fast-paced technology environment where technical expertise, independent ownership, and practical problem-solving are essential. Accountabilities - Application security: Review code, identify vulnerabilities, recommend and implement remediation measures, and collaborate directly with developers through Git and GitHub workflows. - Security testing: Coordinate external penetration tests, security assessments, and audits, ensuring findings are documented, prioritized, and resolved effectively. - Governance, risk, and compliance: Build and maintain the security risk register, assess exposure across systems, support audit follow-ups, and prioritize remediation based on risk severity and business impact. - Security monitoring and threat management: Monitor security alerts, investigate potential threats, respond to emerging incidents, and provide occasional evening and weekend coverage when required.

- Security awareness: Develop and maintain employee security awareness initiatives, conduct phishing simulations, and promote secure working practices across the organization. - IT security and access management: Manage secure employee onboarding and offboarding, device security and mobile device management (MDM), access permissions, and internal security controls. - AI security: Identify and monitor vulnerabilities affecting generative AI platforms, including prompt injection, jailbreaks, safety-filter bypasses, and risks associated with third-party AI providers. - Security operations ownership: Independently identify security gaps, investigate incidents, coordinate remediation, and establish practical security processes that evolve alongside the platform. - Cross-functional collaboration: Work closely with engineering leadership and development teams to integrate security into development workflows and ensure security decisions align with technical requirements and business priorities. - Continuous improvement: Stay informed about emerging cybersecurity threats, AI security developments, and industry best practices to strengthen the platform's overall security posture. Requirements - At least 2–3 years of hands-on experience in security engineering, application security, or a closely related cybersecurity role, with flexibility for candidates who demonstrate exceptional experience in a scale-up environment. - Strong application security expertise, including code reviews, vulnerability identification, security testing, and practical remediation. - Proven experience conducting or coordinating security audits and penetration tests, including tracking findings through to resolution. - Comfortable working directly with code, Git, and GitHub, with the ability to collaborate effectively with software engineers. - Practical scripting or automation skills, preferably using Python or Bash, to improve security workflows and operational efficiency.