Principal Machine Learning Engineer, Matching and Recommendations (UK Based)

What you'll do

• Define and lead the technical strategy for AI and Machine Learning systems that power recommendations, ranking, and personalization across Bumble products, delivering measurable improvements in user engagement and safety.
• Design, develop, and deploy production-grade models using modern ML frameworks such as PyTorch, ensuring scalability and reliability in high-traffic environments.
• Build and deploy production AI Agents using raw and fine-tuned foundational Large Language Models (LLMs), along with sub-agents, tools, and MCP integrations.
• Architect end-to-end ML pipelines, integrating data processing (e.g. Spark, Airflow) with model training, evaluation, and deployment workflows.
• Drive experimentation frameworks, including A/B testing and offline evaluation, to continuously improve model performance and product outcomes.
• Partner cross-functionally with Product, Engineering, and Data leadership to translate business challenges into impactful ML solutions, collaborating with purpose and influencing at senior levels.
• Mentor and elevate senior individual contributors, fostering a culture of Excellence, Curiosity, and continuous learning across the ML community.
• Take ownership of complex, ambiguous problem spaces, seeing initiatives through from insight to impact while adapting approaches with an agile mindset.
• Champion responsible AI practices, ensuring fairness, transparency, and user safety are embedded into all machine learning systems.

About You

• Typically requires 10–15 years of experience, though we welcome candidates with alternative backgrounds that demonstrate equivalent skills.
• Deep expertise in machine learning, with hands-on experience building and deploying large-scale systems in production environments.
• Strong proficiency in Python and at least one major ML framework (e.g. PyTorch, TensorFlow), with experience in areas such as recommendation systems, ranking models, or NLP.
• Expertise in prompting and fine-tuning Large Language Models (LLMs) and building production AI Agents.
• Proven experience designing scalable data and ML pipelines using tools such as Spark, Airflow, or similar distributed systems.
• Demonstrated ability to operate as a senior individual contributor, influencing technical strategy and decision-making without direct authority.
• Experience partnering effectively across functions, collaborating with purpose and taking ownership of outcomes in complex organisational environments.
• A track record of mentoring and uplifting others, role modelling Respect and Excellence while building inclusive, high-performing teams.
• Strong AI fluency, with the ability to independently design, evaluate, and optimise ML systems, and guide others in the responsible and effective application of AI.

Benefits & Perks

• Annual personal learning & development budget
• Private Medical Insurance (PMI)
• Private Dental Insurance
• Babylon Health app
• Mental health support
• Enhanced parental leave, including a highly competitive maternity package
• Unlimited PTO
• Subsidised gym membership
• ‘Double matched’ pension contributions up to 6%
• Premium App Access

Inclusion at Bumble Inc.

Bumble Inc. is an equal opportunity employer and we strongly encourage people of all ages, colour, lesbian, gay, bisexual, transgender, queer and non-binary people, veterans, parents, people with disabilities, and neurodivergent people to apply. We're happy to make any reasonable adjustments that will help you feel more confident throughout the process, please don't hesitate to let us know how we can help.

AI in Bumble Inc. Hiring

At Bumble, we may use AI tools to support parts of our recruitment process — such as helping us record, transcribe, and summarize conversations, and supporting job alignment by comparing resumes and job descriptions to highlight skills and potential roles that may be a good match. These tools help us work more efficiently and stay focused on you during our conversations. Importantly, all hiring decisions are made by people. AI is used only to support our team’s efficiency and improve the candidate experience — not to evaluate or decide on your candidacy.