Company Description

We’re Checkout.com – you might not know our name, but companies like eBay, ASOS, Klarna, Uber Eats, and Sony do. That moment when you check out online? We make it happen.

Checkout.com is where the world checks out. Our global network powers billions of transactions every year, making money move without making a fuss. We spent years perfecting a service most people will never notice. Because when digital payments just work, businesses grow, customers stay, and no one stops to think about why.

With 19 offices spanning six continents, we feel at home everywhere – but London is our HQ. Wherever our people work their magic, they’re fast-moving, performance-obsessed, and driven by being better every day. Ideal. Because a role here isn’t just another job; it’s a career-defining opportunity to build the future of fintech.

As a Senior AI Engineer within Checkout.com’s AI Centre of Excellence, you will drive the adoption of cutting-edge Generative AI technologies to transform how we operate and innovate. You will mentor peers, set engineering best practices, and shape Checkout.com’s AI strategy, while also designing, building, and deploying AI solutions that enhance products and streamline business processes in collaboration with cross-functional teams.

How you’ll make an impact:

• 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 (e.g., chatbots, assistants, knowledge extraction tools).

• Architect scalable AI infrastructure on cloud platforms (AWS, GCP, or Azure), leveraging containerisation and IaC.

• 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.

What we're looking for:

• Hands-on experience with LLMs (e.g., GPT, BERT, Llama, Gemini) and applying them to real-world problems.

• Strong backend engineering expertise, including RESTful APIs and micro-services design.

• Proficiency in Python/JavaScript and familiarity with AI frameworks (e.g., Lang Chain, PydanticAI).

• Solid understanding of cloud computing (AWS, GCP, or Azure), containerisation (Docker, Kubernetes), and Infrastructure-as-Code (Terraform).

• Proven problem-solving skills and ability to thrive in fast-paced environments.

• Excellent communication and collaboration skills across diverse teams.

Preferred qualifications:

• Proficiency in C# or Java.

• Frontend development experience with JavaScript/TypeScript and frameworks such as React.

• Experience developing Generative AI applications, including model fine-tuning and prototyping.

• Awareness of ethical AI practices and emerging standards in AI governance.

• Track record of rapid prototyping with measurable ROI.

• Familiarity with distributed systems and large-scale data processing.

• Contributions to open-source projects or a strong GitHub portfolio.

• High technical curiosity and eagerness to learn new platforms.

• Experience in the payments industry (a strong plus).

Additional Information Bring all of you to work

We create the conditions for high performers to thrive, through real ownership, fewer blockers, and work that makes a difference from day one.

Here, you’ll move fast, take on meaningful challenges, and be recognized for the impact you deliver. It’s a place where ambition gets met with opportunity, and where your growth is in your hands.

We work as one team, and we back each other to succeed. So whatever your background or identity, if you’re ready to grow and make a difference, you’ll be right at home here.

It’s important we set you up for success and make our process as accessible as possible. So let us know in your application, or tell your recruiter directly, if you need anything to make your experience or working environment more comfortable.

Life atCheckout.com

We understand that work is just one part of your life. Our hybrid working model offers flexibility, with three days per week in the office to support collaboration and connection.

Curious about what it’s like to be part of our team? Visit our Careers Page to learn more about our culture, open roles, and what drives us.

For a closer look at daily life at Checkout.com, follow us on LinkedIn and Instagram