Senior Software Engineer, AI Centre of Excellence

Salary: £45,000 - 83,000 per year

Requirements:

• Hands-on experience with LLMs such as GPT, BERT, Llama, or Gemini and applying them to real-world problems.
• Strong backend engineering expertise, including RESTful APIs and microservices design.
• Proficiency in Python or JavaScript and familiarity with AI frameworks such as LangChain or PydanticAI.
• Solid understanding of cloud computing on AWS, GCP, or Azure, containerisation with Docker and Kubernetes, and Infrastructure as Code with Terraform.
• Proven problem-solving skills and ability to thrive in fast-paced environments.
• Excellent communication and collaboration skills across diverse teams.
• Proficiency in C# or Java is preferred.
• Frontend development experience with JavaScript/TypeScript and frameworks such as React is preferred.
• Experience developing Generative AI applications, including model fine-tuning and prototyping, is preferred.
• Awareness of ethical AI practices and emerging standards in AI governance is preferred.
• Track record of rapid prototyping with measurable ROI is preferred.
• Familiarity with distributed systems and large-scale data processing is preferred.
• Contributions to open-source projects or a strong GitHub portfolio are preferred.
• High technical curiosity and eagerness to learn new platforms are preferred.
• Experience in the payments industry is a strong plus.

Responsibilities:

• Partner with product managers, data scientists, and engineers to research, validate, and deliver high-impact Generative AI use cases.
• Design and build APIs and microservices that integrate AI capabilities into internal and external workflows.
• Develop, fine-tune, and deploy LLM-based applications such as chatbots, assistants, and knowledge extraction tools.
• Architect scalable AI infrastructure on cloud platforms such as AWS, GCP, or Azure, leveraging containerisation and Infrastructure as Code.
• Implement CI/CD pipelines and enforce best practices for secure, compliant AI deployment.
• Build intuitive interfaces that enable teams to interact effectively with AI-driven features.
• Continuously optimise performance, reliability, and scalability of AI systems.
• Mentor peers, set engineering best practices, and help shape our AI strategy.

Technologies:

• AI
• AWS
• Architect
• Azure
• Backend
• C#
• CI/CD
• Cloud
• Docker
• Fine-tuning
• Frontend
• GCP
• GitHub
• Support
• Java
• JavaScript
• Kubernetes
• LLM
• Python
• React
• Terraform
• TypeScript
• microservices

More:

We are Checkout.com, a global fintech company powering digital experiences for brands like eBay, Spotify, Klarna, Uber, and Sony. We enable over 10 billion transactions annually for more than one billion shoppers worldwide, and our platform helps ambitious businesses deliver seamless payments at scale. As part of our AI Centre of Excellence, you will help drive the adoption of cutting-edge Generative AI technologies to transform how we operate and innovate. We offer a fast-paced, globally minded environment with 20 offices across six continents and our HQ in London. We support high performers with real ownership, fewer blockers, meaningful work from day one, and a hybrid working model with three days per week in the office.

last updated 36 week of 2026