Machine Learning Engineer II in London

Amex GBT is a place where colleagues find inspiration in travel as a force for good and – through their work – can make an impact on our industry. We’re here to help our colleagues achieve success and offer an inclusive and collaborative culture where your voice is valued.

Location: London, UK (hybrid)

Amex GBT is at the center of revolutionizing business travel with our cutting‑edge technology and the most desirable products in the industry. We’re a global, product‑focused AI team with hubs in Bellevue, Chicago, Paris, London, Gurgaon, and now extending to Manchester. Since 2017, we’ve been delivering AI systems at scale – from ranking models and savings optimization engines to client‑facing LLM‑powered experiences used by business travelers worldwide.

We are looking for a Machine Learning Engineer II to join our Product AI Engineering team. You will help us design, build, and optimize intelligent systems. This is not just a modeling role; you’ll own the full lifecycle: from raw data to deployed models / compound systems to measurable business impact. If you’re passionate about solving real‑world problems at scale, collaborating across disciplines, travel, and making AI systems that truly matter – this is for you.

What You’ll Be Doing

• Utilize AI techniques, including machine learning, deep learning, generative AI, and statistical modeling, to develop and implement solutions for tackling real‑world problems such as ranking, chatbot, intent recognition, agentic AI systems, recommender systems, computer vision, NLQ etc.
• Apply strong coding skills, analytical abilities, and innovative thinking to quickly understand new domains and transform creative ideas into functional solutions.
• Employ statistical and data science methods to make data‑driven decisions.
• Manipulate large data sets for business insights and drive actionable solutions.
• Utilize appropriate methods and approaches to develop practical solutions for the business.
• Structure work, frame issues, and produce analyses/ML models/Compound AI systems that answer complex business questions in a pragmatic approach.
• Communicate complex data science topics in a clean & simple way to multiple partners and senior leadership.
• Collaborate with a global team across different continents to achieve project goals.

What We’re Looking For

• 6+ years of experience with a bachelor’s degree or equivalent, or 3+ years with a master’s degree or equivalent.
• Proven ability to conceptualize business problems and solve them through data science solutions.
• Proven knowledge of AI techniques such as Bayesian methods, Clustering, Ensemble tree models, NLP, etc., with an excellent grasp of statistical concepts and methods.
• Good understanding of LLMs, guardrails, RAG, agentic AI.
• Strong passion for solving problems and finding patterns and insights within structured and unstructured data.
• Industry experience in leveraging AI techniques on real‑world large data sets.
• Understanding of the concepts and steps involved in working with real‑world large data sets: from domain‑specific problem understanding, data preparation, travel‑related data processing, feature engineering, data structures for ML, data pipelining, modeling, offline evaluation, online evaluation, and monitoring.
• Strong knowledge of hands‑on practice in Python. Familiarity with popular machine learning libraries and frameworks such as scikit‑learn, Hugging Face, PyTorch and TensorFlow.
• Experience with MLFlow, AWS SageMaker and Bedrock is preferred.
• Familiar with MLOps concept.
• Comfortable with data cleansing using SQL and PySpark.
• Good written and oral communication skills, including the ability to communicate across business areas and increase overall knowledge across the organization.
• Experience with feature stores, machine learning models as service, and monitoring dashboards is a plus.
• Some infrastructure knowledge (AWS, Kubernetes) and cost‑awareness are a plus.

#TeamGBT Experience

• Flexible benefits are tailored to each country and start the day you do. These include health and welfare insurance plans, retirement programs, parental leave, adoption assistance, and wellbeing resources to support you and your immediate family.
• Travel perks: get a choice of deals each week from major travel providers on everything from flights to hotels to cruises and car rentals.
• Develop the skills you want when the time is right for you, with access to over 20,000 courses on our learning platform, leadership courses, and new job openings available to internal candidates first.
• We strive to champion Inclusion in every aspect of our business at Amex GBT. You can connect with colleagues through our global Inclusion Groups, centered around common identities or initiatives, to discuss challenges, obstacles, achievements, and drive company awareness and action.
• And much more!

Location: London, United Kingdom

All applicants will receive equal consideration for employment without regard to age, sex, gender (and characteristics related to sex and gender), pregnancy (and related medical conditions), race, color, citizenship, religion, disability, or any other class or characteristic protected by law. Furthermore, we are committed to providing reasonable accommodation to qualified individuals with disabilities. Please let your recruiter know if you need an accommodation at any point during the hiring process. For details regarding how we protect your data, please consult the Amex GBT Recruitment Privacy Statement.

What if I don’t meet every requirement? If you’re passionate about our mission and believe you’d be a phenomenal addition to our team, don’t worry about “checking every box”; please apply anyway. You may be exactly the person we’re looking for!