Job Description

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 Staff Data Scientist specialising in the AI Centre of Excellence you will lead LLM-based solutions' design, development, and deployment, collaborating with cross-functional teams to deliver impactful AI-driven applications across our business.

How you'll make an impact:

In collaboration with product managers and engineers, research, scope and validate use cases where LLMs can improve Checkout.com's product features and business processes Design, develop, and fine-tune LLMs for various applications such as chatbots, virtual assistants, text generation, and more. Ensure we have the right processes and tools to curate and preprocess large datasets for training and evaluating LLMs, implement strategies for data augmentation, labeling, and annotation. As the technical thought leader, increase the AI fluency in the wider business through supporting training programs and mentoring others. Ensure that LLM applications adhere to ethical standards and comply with relevant regulations.

Qualifications:

Proven track record of developing and deploying LLM-based solutions in an enterprise setting as a senior/staff scientist. Proficiency in Python and libraries such as TensorFlow, PyTorch, Hugging Face Transformers, and spaCy.Strong understanding of LLM architectures (e.g., GPT, BERT, T5) and experience fine-tuning them for specific tasks. Demonstrable experience in utilising different model architectures and training techniques to optimise performance Familiarity with prompt engineering techniques and frameworks like LangChain, LlamaIndex, or DSpy. Good understanding of LLM models, including other components like VectorDBs and document loaders. Strong analytical and problem-solving skills, with the ability to work with complex datasets and extract meaningful insights. Excellent verbal and written communication skills, with the ability to explain complex technical concepts to non-technical stakeholders. Strong ability to collaborate and communicate with a large and varied group of stakeholders to embed AI into workflows and product features.

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