Senior Software Security Developer – Core Platform Services

Overview

We are recruiting for a Senior Software Security Developer within our Core Platform Services Team. You will be responsible primarily for writing secure code components that many teams will use across the business. There is a strong emphasis on authentication for this role.

Responsibilities

• Design and implement platform security features and guardrails.
• Act as an SME for security for the Core Services development team. This includes mentoring, performing threat modeling, and security code reviews.
• Help shape incident response procedures and vulnerability management workflows.
• Support the response team by validating and remediating product security vulnerabilities.
• Contribute to secure coding standards and provide training/mentorship to developers.

Qualifications

• 8+ years in a developer role focused with strong focus on designing and building security features.
• Extensive RBAC/ABAC knowledge and implementation experience.
• Experience with user, agent, and machine authentication workflows.
• Hands-on experience with secure coding, OWASP Top 10, and threat modeling.
• Strong developer skills and extensive experience shipping code to production.
• Experienced in CI/CD, IaC, Python and Go.
• Track record of balancing pragmatism and security rigor in a fast-paced team.
• Thorough knowledge of authentication and authorization protocols (e.g., OAuth, OpenID Connect, SAML, LDAP, etc.).
• Strong communication skills, comfortable working across development teams and managing multiple initiatives.

Nice to Have

• Strong understanding of AI security fundamentals.
• Participation in bug bounty programs.
• Familiarity with the BSIMM framework.
• Experience in cloud security including identity and access management and cloud-native services.

Location & Benefits

London. Salary: £44,300 per year (contract). PhysicsX is a deep-tech company with roots in numerical physics and Formula One, focusing on accelerating hardware innovation at the speed of software. We offer an AI-driven simulation software stack for engineering and manufacturing across advanced industries, enabling high-fidelity multi-physics simulation through AI inference across the engineering lifecycle.

• Equity options – share meaningfully in the company you’re helping to build.
• 10% employer pension contribution.
• Free office lunches.
• Enhanced parental leave – 3 months full pay paternity and 6 months full pay maternity leave.
• YellowNest nursery scheme for childcare support.
• 25 days of annual leave (+ public holidays).
• Private medical insurance – 100% employee cover.
• Wellhub Subscription for wellness resources.
• Eye tests and support for health and wellbeing.
• Personal development support for learning and growth.
• Employee Assistance Programme (EAP).
• Bike2Work scheme and Season ticket loan.
• Octopus EV salary sacrifice program.

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