Senior SDET

Radiant; Greater London; On-site; GBP 80,000 - 120,000; Full time

Benefits offered by this job

25 days annual leave

Private medical insurance (Bupa)

Cycle to Work Scheme

Gympass subscription

Company shares program

Enhanced parental pay & leave

Job summary

Radiant is seeking a Senior SDET with strong Go and Kubernetes expertise to design and build cloud-native back-end systems and scalable APIs for AI workloads, including LLMs and GPU-based services. You will create robust test automation frameworks, build testing strategies across API, integration, end-to-end, performance and reliability testing, and mentor junior engineers to raise quality standards.

Collaborating with platform, backend, and ML teams, you’ll ensure reliability, data integrity,

Qualifications

• Experience designing test automation frameworks in Go
• Hands-on testing of distributed systems and APIs in production
• Strong knowledge of API testing (gRPC/REST) and performance testing
• Ability to improve software quality through automation and reviews

Responsibilities

• Design, develop and maintain automated test frameworks in Go
• Build and implement automated testing strategies across API, integration, end-to-end, performance and reliability testing
• Develop test automation for secure, reliable APIs and backend systems
• Collaborate with UI/UX and frontend teams to embed quality throughout the product lifecycle
• Work with relational databases to validate data integrity and performance
• Design and run tests for Kubernetes deployments using Helm and the Kubernetes API
• Contribute to architectural discussions with a focus on testability and reliability
• Maintain high standards for observability and maintainability through automation and reviews

Skills

Golang

Kubernetes

Test automation

Distributed systems

API testing

CI/CD

Tools

Helm

PostgreSQL

Kubernetes API

Docker

Job description

About the role

We’re looking for a Senior SDET 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, backend, and machine learning engineers - to design, develop, and maintain scalable test automation frameworks and quality engineering solutions. You’ll help ensure the reliability, performance, and quality of systems that power model training, inference, and orchestration in production environments, while mentoring junior engineers, championing quality best practices, and driving initiatives to improve test coverage, release confidence, and overall software quality.

What You’ll Do:

• Design, develop and maintain robust automated test frameworks and quality engineering solutions in Go
• Build and implement automated testing strategies across API, integration, end-to-end, performance, and reliability testing
• Develop and maintain test automation for secure, reliable APIs (gRPC/REST) and backend systems
• Collaborate closely with UI/UX designers and front-end engineers to ensure quality is embedded throughout the product development lifecycle and identify potential usability, reliability, and performance risks and drive quality-focused improvements before implementation
• Work with PostgreSQL or similar relational databases to validate data integrity, performance, and reliability
• Design and execute testing solutions for applications deployed on Kubernetes, leveraging Helm charts and the Kubernetes API
• Collaborate in architectural discussions, providing quality-focused input on system design, testability, scalability, and reliability
• Maintain high standards for software quality, observability, and maintainability through automation, reviews, and best practices

What you bring:

• Proven experience developing and maintaining test automation frameworks in Golang
• Hands-on experience testing distributed systems and APIs (gRPC, REST) in production environments
• Strong experience with automated testing methodologies including unit, integration, end-to-end, regression, and performance testing
• Proven ability to improve software quality through automation, code reviews, root cause analysis, and adherence to quality engineering principles
• Deep knowledge of Kubernetes and cloud-native architectures from a testing and reliability perspective
• Hands-on experience with containers, Helm, CI/CD pipelines, and microservice testing strategies
• Experience working with test reporting, observability, and quality metrics to drive continuous improvement
• Ability to work autonomously with a proactive, solution-oriented mindset
• Experience collaborating effectively with developers, product teams, and cross-functional stakeholders
• Good understanding of front-end testing methodologies and tools, with experience validating complex user workflows across modern web applications

Preferred Skills (Nice to Have)

• Strong understanding of modern DevOps workflows and CI/CD practices
• Experience building automated testing solutions for AI/ML platforms, LLM-serving infrastructure, or GPU workloads (e.g., vLLM, KServe)
• Experience with performance, load, resilience, and scalability testing of distributed systems
• Experience implementing quality gates and automated testing within CI/CD pipelines
• Familiarity with cloud platforms and infrastructure testing

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.