Senior Software Security Engineer – Core Platform Services

Mesh-AI Limited; Greater London; On-site; GBP 70,000 - GBP 90,000; Full time

Job summary

A deep-tech company in London is seeking a Senior Software Security Engineer to enhance platform security through secure code. The ideal candidate will have over 8 years of experience in a developer role, focusing on security, and will be responsible for designing security features and mentoring development teams. Additional skills in authentication workflows, threat modeling, and secure coding standards are essential. This role offers a chance to work in a diverse and inclusive environment.

Qualifications

• 8+ years in a developer role focused on security features.
• Hands-on experience with secure coding and OWASP Top 10.
• Thorough knowledge of authentication and authorization protocols.

Responsibilities

• Design and implement platform security features.
• Mentor the Core Services development team on security.
• Shape incident response procedures and vulnerability management.

Skills

Secure coding

RBAC/ABAC knowledge

Threat modeling

Authentication workflows

CI/CD

Python

Go

Communication

Job description

Senior Software Security Engineer – Core Platform Services

London

About us

PhysicsX is a deep-tech company with roots in numerical physics and Formula One, dedicated to accelerating hardware innovation at the speed of software.

We are building an AI-driven simulation software stack for engineering and manufacturing across advanced industries. By enabling high-fidelity, multi-physics simulation through AI inference across the entire engineering lifecycle, PhysicsX unlocks new levels of optimization and automation in design, manufacturing, and operations — empowering engineers to push the boundaries of possibility. Our customers include leading innovators in Aerospace & Defense, Materials, Energy, Semiconductors, and Automotive.

The Role

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

What you will do

• 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, sand ecurity 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

What you bring to the table

• 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 Skills

• 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.

We value diversity and are committed to equal employment opportunity regardless of sex, race, religion, ethnicity, nationality, disability, age, sexual orientation or gender identity. We strongly encourage individuals from groups traditionally underrepresented in tech to apply. To help make a change, we sponsor bright women from disadvantaged backgrounds through their university degrees in science and mathematics.

We collect diversity and inclusion data solely for the purpose of monitoring the effectiveness of our equal opportunities policies and ensuring compliance with UK employment and equality legislation. This information is confidential, used only in aggregate form, and will not influence the outcome of your application.