Senior AppSec Lead: Threat Modelling & Secure Testing

Global Relay; Greater London; On-site; GBP 90,000 - 130,000; Full time

Job summary

Global Relay seeks a Senior Application Security Specialist to lead advanced testing, threat modelling and security strategy across its applications. You will mentor analysts, liaise with engineering, and shape standards in a high‑impact security program.

You will own testing frameworks, automation, and KPI reporting, while driving remediation and security release processes. Strong leadership and deep technical expertise are essential for success.

Qualifications

• 5–8 years' hands-on experience in application security testing.
• Strong knowledge of internet and network technologies.
• Expert understanding of web and API technologies and vulnerabilities.
• Experience with mobile security testing and Frida scripting is a plus.
• RBAC, container security and Kubernetes hardening experience.
• Familiarity with MITRE ATT&CK and threat actor tactics.
• Ability to automate test cases and integrate with CI/CD tools.

Responsibilities

• Lead advanced security testing of critical applications and services across web, mobile and API surfaces.
• Own threat modelling using structured frameworks (STRIDE, PASTA) for new features.
• Support and engage in the penetration testing programme.
• Design security test strategies for new products and major changes.
• Act as SME and primary security contact between engineering and the Application Security team.
• Oversee scanning-tool usage and KPIs in the CI/CD pipeline.
• Own triage, escalation and evidence quality across testing streams.
• Track security metrics and report to senior stakeholders.
• Build advanced test cases, automation frameworks and tooling.
• Own the security release process and remediation verification.
• Mentor analysts; prepare training materials and playbooks.

Skills

Application security testing

Threat modelling

Penetration testing

OWASP Top 10

Kubernetes security

CI/CD security

Python scripting

Communication

OSCP/OSWE

Job description

Global Relay seeks a Senior Application Security Specialist to lead advanced testing, threat modelling and security strategy across its applications. You will mentor analysts, liaise with engineering, and shape standards in a high‑impact security program.

You will own testing frameworks, automation, and KPI reporting, while driving remediation and security release processes. Strong leadership and deep technical expertise are essential for success.