Principal Backend Software Engineer
Radiant · London
What this role requires
3 requirements, read out of the advert rather than guessed from the job title:
Also mentioned, not required: gRPC, REST, CI/CD, English (B2). Worth having, but their absence is not what gets a CV filtered out.
See how often each of these is required across open backend roles in Europe.
Free, no card. Tells you which of them your CV evidences and which it only implies.
Job description
About the Role
As a Principal Software Engineer at Radiant, you’ll be a hands-on technical leader, driving the design and development of our most critical systems, including our GPU orchestration layer, inference-serving infrastructure, and core platform APIs.
You’ll set the standard for engineering excellence across the team, working closely with other principal engineers to align on strategy and drive technical leadership. You’ll partner with peers in infrastructure and machine learning to deliver high-performance AI systems, and mentor engineers across multiple squads. While you won’t have direct reports, you’ll play a pivotal role in shaping engineering direction, design decisions, and cross-team collaboration.
What You’ll Do:
Design and develop core services for the Radiant AI Cloud
Architect and build core backend services in Go that power AI infrastructure, networking, inference orchestration, and model lifecycle management
Read the full description (44 more sections)Show less
Lead engineering design efforts across the backend domain - architecture reviews, and system evolution strategies
Collaborate closely with platform and infrastructure to deliver reliable, secure, production-grade services
Drive technical standards and mentorship, upholding code quality, observability, and maintainability across teams
Proactively identify and resolve architectural bottlenecks, performance issues, or scaling challenges
What you bring:
Proven expertise in Golang and cloud-native backend development
Deep experience designing and deploying distributed systems and APIs (gRPC, REST) in production environments
Strong knowledge of Kubernetes internals, with deep understanding of primitives, deployments and reconciliation loops.
Experience with PostgreSQL or equivalent high-performance data stores
Experience with CI/CD workflows, observability, security and automation best practices
Demonstrated ability to lead technically: mentor others, drive architectural thinking, and influence across teams
A bias for action, accountability, and leading by example
Preferred Skills (Nice to Have)
Experience with AI/ML infrastructure tooling (e.g. vLLM, KServe, Ray, Triton)
Familiarity with Python, especially ML libraries and model interfaces
Familiarity with GPU scheduling, inference pipelines, or resource-constrained workload orchestration
Exposure to GPU orchestration frameworks or building services for model training/inference
Understanding of multi-tenant systems, isolation strategies, and secure infrastructure for AI workloads
How you work:
You approach problems with a systems mindset - balancing practical execution with long-term scalability
You elevate the team, setting high standards for technical quality and engineering excellence.
You hold yourself and others accountable - giving direct feedback and expecting the same
You take initiative, owning challenges end-to-end and proactively driving solutions.
You invest in others, mentoring to build both capability and confidence.
You communicate clearly - translating complexity into clarity across engineering and business audiences
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 feedbac k: 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
Diversity, Equality, Inclusion and Belonging
We are an equal opportunity employer and we strive to reduce unconscious bias throughout our hiring process. All applicants will be considered for employment without attention to ethnicity, religion, sexual orientation, gender identity, family or parental status, national origin, veteran, neurodiversity status or disability status. To ensure our recruitment processes provide an equal opportunity for all applicants to succeed, we encourage you to let us know if there are any adjustments that we can make.
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