Senior Application Security Engineer - Product Security & DevSecOps

The opportunity

We are seeking an experienced Senior Application Security Engineer to take ownership of security across our software development lifecycle (SDLC). In this role, you will establish secure delivery as the default for our engineering teams, from design and code through to the pipelines that release it.

You will own our Application Security Posture Management (ASPM) platform, Ox Security, and ensure its findings translate into effective remediation. This includes reducing noise, prioritising vulnerabilities that are genuinely exploitable and partnering closely with engineering teams to resolve them. You will also define our approach to threat modelling, security testing and the integration of security guardrails into our CI/CD pipelines.

You will join a small, collaborative Information Security team based across London and Wrocław, working alongside our Senior Security Engineer (Cloud & SecOps) and our Governance, Risk and Compliance (GRC) function. You will work closely with our Engineering teams on a day-to-day basis and report to the Head of Information Security.

Key responsibilities

Secure SDLC and pipeline security

• Own security across our SDLC and CI/CD pipelines, embedding secure delivery as the default
• Build and maintain pipeline security guardrails, including static application security testing (SAST), software composition analysis (SCA), secrets scanning, and infrastructure-as-code (IaC) and container image scanning, with gating policies agreed with Engineering
• Strengthen software supply chain security, including dependency hygiene, software bills of materials (SBOMs) and build provenance
• Define pre-deployment cloud guardrails through policy-as-code, in partnership with our Senior Security Engineer (Cloud & SecOps)

Vulnerability management and remediation

• Own Ox Security as our ASPM platform, including policy tuning, noise reduction and the prioritisation of findings based on reachability and exploitability
• Drive remediation with engineering teams, agreeing remediation service level agreements (SLAs) with engineering leads and reporting clearly on progress
• Scope and coordinate application penetration testing, tracking findings through to remediation

Secure design and engineering enablement

• Lead threat modelling for new features and significant architectural changes
• Conduct secure design reviews and review high-risk code changes
• Promote secure coding practices through practical guidance, training and a security champions network across Engineering

Client assurance, reporting and threat awareness

• Represent our platform security with confidence in client security reviews and due diligence discussions, alongside the Head of Information Security
• Maintain and report application security metrics that inform risk reporting and key risk indicators (KRIs)
• Support audits and client assurance activities with clear evidence of our secure development and release practices
• Monitor emerging application and supply chain threats, including those affecting AI and agentic capabilities

Skills and experience

• Proven experience in an application security, product security or DevSecOps role, ideally within a SaaS environment
• Hands-on experience integrating security tooling into CI/CD pipelines
• A track record of converting SAST, SCA, secrets or ASPM findings into prioritised, remediated work rather than raw reporting
• Strong understanding of common vulnerability classes and the OWASP Top 10, with practical knowledge of how to remediate them
• The ability to read and review code in at least one of our core languages: Java, Ruby or Python
• Experience facilitating threat modelling with engineering teams
• Working knowledge of AWS and infrastructure-as-code
• Proficiency in Python or a comparable scripting language for automation
• Credibility with developers, with the ability to influence engineering teams and articulate risk in actionable terms

Desirable

• Hands-on experience with Ox Security or another ASPM platform
• A background in software engineering prior to moving into security
• Software supply chain security experience, such as Supply-chain Levels for Software Artifacts (SLSA), SBOMs or artefact signing
• Container and Kubernetes security experience, including image scanning and admission controls
• Experience with policy-as-code tooling
• Experience establishing a security champions programme
• Experience securing large language model (LLM) or agentic AI capabilities, such as applying the OWASP Top 10 for LLM Applications
• Familiarity with financial services regulations and standards, such as the Digital Operational Resilience Act (DORA), ISO 27001 and SOC 2
• Relevant professional certifications, such as OSWE, GWAPT, CSSLP or AWS Certified Security – Specialty

The reward package

• Competitive salary package aligned with your skills and experience. Reviewed annually.
• Annual Performance-based bonus
• Healthcare cashback scheme and private medical insurance
• 4X salary life assurance
• Unlimited annual holiday, because we trust our people to manage their own time off
• Enhanced family leave
• Employee Assistance Programme
• Cycle to Work and Tech Scheme
• 4 Volunteering days off
• Flexible working policy (2 days per week in office)
• Opportunity to work abroad for up to 6 weeks per year
• Personal learning and development opportunities
• Referral bonus if we hire someone great who you’ve recommended to us
• Spot Rewards
• Employee of the Month and Employee of the Year awards