Senior Backend Software Engineer - Core Services in London

About Radiant

We’re looking for a Senior Software Engineer with strong experience in Golang and Kubernetes to join our core product team. In this role, you'll design and build high-performance, cloud-native back-end systems and scalable APIs to support AI workloads, including LLMs and GPU-based services. You’ll collaborate closely with cross-functional teams - including platform and machine learning - to design, develop, and deliver high-quality software solutions. You’ll help build tools and services that power model training, inference, and orchestration in production environments, while mentoring junior engineers, upholding engineering best practices, and driving initiatives to improve code quality and system performance.

What You’ll Do:

• Design, develop, and maintain robust applications and services in Go
• Implement secure, reliable APIs (gRPC/REST) and backend systems
• Work with PostgreSQL or similar relational databases for high-performance querying and storage
• Deploy and operate applications in Kubernetes, leveraging Helm charts and the Kubernetes API
• Contribute to architectural discussions, providing input on design reviews and system evolution
• Maintain high standards for code quality, observability, and maintainability through reviews and best practices

What you bring:

• Proven experience developing production systems in Golang
• Hands-on experience designing and deploying distributed systems and APIs (gRPC, REST) in production environments
• Proven ability to improve software quality through unit testing, integration testing, code reviews, and adherence to clean code principles
• Deep knowledge of Kubernetes and cloud-native architectures
• Hands-on experience with containers, Helm, and microservice design patterns
• Ability to work autonomously with a proactive, solution-oriented mindset
• Experience collaborating effectively with front-end developers and cross-functional teams.

Preferred Skills (Nice to Have)

• Strong understanding of modern DevOps workflows and CI/CD practices
• Experience deploying or serving LLMs or other GPU workloads (e.g., using vLLM, KServe)
• Experience tuning and scaling machine learning inference pipelines

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.

Salary Range Information

Based on market data and other factors, the salary range for this position is £50,000-95,000 and will vary depending on the candidate's experience.

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: we value your peace of mind. With 30 days off (excluding public holidays) and access to mental health resources, we make sure you're as strong mentally as you are professionally.
• 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

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.