Senior Software Engineer, AI Centre of Excellence Software engineering London

Checkout; Greater London; On-site; GBP 110,000 - 160,000; Full time

Job summary

Checkout.com is seeking a Senior AI Engineer to drive Generative AI adoption across the business. You will mentor peers, shape AI strategy, and build AI solutions that enhance products and processes in collaboration with cross-functional teams.

You’ll partner with product managers, data scientists, and engineers to research, validate, and deliver high-impact AI use cases, while designing scalable APIs and cloud infrastructure.

Qualifications

• Hands-on experience applying LLMs to real-world problems.
• Strong backend APIs and microservices design.
• Proficiency in Python/JavaScript with AI frameworks.

Responsibilities

• Research, validate, and deliver high-impact Generative AI use cases.
• Design and build APIs/microservices that integrate AI into workflows.
• Develop, fine-tune, and deploy LLM-based applications.
• Architect scalable AI infrastructure on cloud platforms.

Skills

LLMs

Backend APIs

Python/JavaScript

Cloud platforms

Docker/Kubernetes

Terraform

LangChain

PydanticAI

AI governance

Tools

Docker

Kubernetes

Terraform

LangChain

PydanticAI

Job description

Company Description

We’re Checkout.com. You might not know our name, but companies like eBay, Spotify, Klarna, Uber, and Sony do, because we’re behind many of the digital experiences you use every day.

We are where the world checks out, enabling over 10 billion transactions yearly for more than one billion global shoppers.

Whether you want to book a holiday, order food, renew a subscription, or check out online, there’s a good chance our tech powers the payments behind the scenes. Our platform helps the most ambitious businesses deliver effortless digital experiences, at scale.

If you want to do career-defining work, you’ve come to the right place. We move fast, think globally, and believe great teams are built by hiring exceptional people with conviction, curiosity, and the desire to make an impact.

With 20 offices across six continents and London as our HQ, we’re shaping the future of fintech – and we’re just getting started.

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., LangChain, 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 at Checkout.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.