Senior Backend Software Engineer - Core Services at radiant – London | Jobyssey

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 servingLLMs 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.

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

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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