Principal Software Engineer - Security

Radiant, United Kingdom

What you will do

What you'll do

As a Principal Software Engineer – Security, you will help set the technical direction for Radiant's security capabilities across the cloud platform and infrastructure, leading the design and delivery of the systems that underpin them.

You'll work across identity, access control, secrets, network security, platform hardening, auditability, and compliance controls. You'll partner closely with product, infrastructure, SRE, networking, security, and compliance teams, and with customers on their most demanding security requirements.

This is a hands-on technical leadership role focused on making security embedded, scalable, automated, and easy to consume across the platform, through architecture, code, and the standards other teams build on.

What you need

Your profile

Strong hands-on engineering skills in one or more systems languages such as Go or similar.
Extensive experience building and operating large-scale distributed systems, with significant depth in cloud and network security, IAM, or security infrastructure.
A track record of technical leadership at staff or principal level, including setting direction across multiple teams and delivering complex, high-stakes systems.
Deep technical expertise across:
Identity & access: IAM, RBAC/ABAC, OAuth 2.0, OIDC, SAML, SSO, federation, mTLS, workload and service identity
Security controls: applied cryptography, encryption at rest and in transit, secrets management, KMS/HSM, key rotation, policy engines
Infrastructure: Kubernetes internals, containers and runtime isolation, cloud networking, compute, storage
Security operations: audit logging pipelines, detection engineering, vulnerability management, incident response
Automation: policy-as-code, infrastructure-as-code, CI/CD security, software supply chain (signing, SBOMs, provenance)
Hands-on experience with technologies such as Vault, OPA/Gatekeeper, SPIFFE/SPIRE, Kubernetes admission control and security tooling, Sigstore, SIEM platforms, cloud KMS, or similar.
Deep understanding of multi-tenancy, least privilege, zero-trust architecture, threat modelling, and shared-responsibility models.
Familiarity with compliance frameworks such as SOC 2 or ISO 27001, and how they translate into technical controls.
Able to balance security, performance, reliability, operational complexity, and developer experience.
Excellent written and verbal communication, including clear design documents and explaining complex trade-offs to technical and non-technical audiences.

What you bring

Security mindset: Think like an attacker and design systems that fail safely, without making them painful to use.
Engineering excellence: Write and review code that sets the standard for correctness, reliability, and maintainability.
Architectural judgement: Make sound long-term decisions on systems that are hard to change once built.
Technical leadership: Influence direction across teams without relying on authority, and grow the engineers around you.
Systems thinking: Understand how controls interact across the full cloud platform, from network and infrastructure up to APIs and user experience.
Ownership: Drive security capabilities from design through production, operation, and continuous improvement.

Qualities we look for

Set the standard: Every single day, you spot opportunities to constructively shake things up
Inspire the change: There's no blueprint for the future. You'll embrace challenges and change
You're real and you're true to yourself: We cherish and celebrate diversity so you'll feel right at home whoever you are and whoever you're talking to, you treat everyone the same.

WHY SHOULD YOU JOIN US?

What sets us apart is our blend of modern technology, competitive benefits, and an open, welcoming work culture that enables our people to thrive.

Here are just some of the great things you can expect from us

25 days of annual leave
A culture that emphasises results over hierarchy, process & ego: we place great emphasis on the quality, ingenuity and creativity of work.
Open communication, regular feedback: we value smooth collaboration, direct and actionable feedback, and believe that leading with empathy and a growth mindset makes us better together.
Learning Time: we all have dedicated learning time to focus on new skills, projects or interests that lay outside of your day-to-day job.
Health & Wellbeing: we want everyone to feel healthy and happy, so we offer private medical insurance via Bupa.
Cycle to Work Scheme: we're committed to building a sustainable business, so we encourage cycling to work.
Gympass subscription to a variety of gyms and wellbeing apps
Participation in the company shares program
Enhanced parental pay & leave

Our process: Talent screen → Hiring Manager → Technical interview (two Principal Engineers) → Whiteboard Session → Final.

Principal Software Engineer - Security

What you will do

What you'll do

Principal Software Engineer - Security

What you will do

What you'll do

Key responsibilities

What you need

Your profile

What you bring

Qualities we look for

Here are just some of the great things you can expect from us

About Radiant

Similar jobs at other companies

Principal Infrastructure Security Engineer

Sr. Security Engineer

Security Engineer

Infrastructure Security Engineer

Senior Technical Program Manager, IT Infrastructure

Member of Technical Staff, Infrastructure Security

Radiant