Staff Machine Learning Engineer – Ads Bidding

Responsibilities

We are representing a confidential marketplace technology client in London who is tackling a genuinely cutting-edge problem in advertising economics. Our client is migrating their advertising platform from cost-per-click to cost-per-order bidding—a complex challenge that very few companies have successfully solved, with no established playbook to follow.

In this role, you will:

• Own the design and execution of the CPC-to-CPO migration, including resolving core strategic questions around whether the system maintains CPO-facing interfaces while optimising CPC internally, or implements a hybrid approach
• Build and improve the bidding infrastructure, including goal-based automated bidding, Target CPO, optimised CPC, and Target ROAS capabilities
• Own yield management systems tied to return-on-spend targeting
• Collaborate daily with distributed engineering teams across time zones to align on technical approach across markets
• Set technical direction for the ads bidding domain and drive decision-making in ambiguous problem spaces
• Partner cross-functionally with product, commercial, and engineering stakeholders to deliver measurable business impact

What We're Looking For

Our client needs someone with deep expertise in advertising economics and marketplace bidding systems. The ideal candidate will have:

• Demonstrated expertise in ad economics, marketplace bidding, or auction theory
• Direct hands-on experience working with optimised CPC, target CPO, goal-based automated bidding, and target ROAS systems
• Strong self-driven leadership—you'll be setting strategic direction in an ambiguous problem space, not executing against established patterns
• 7+ years writing production code in Python with solid ML fundamentals in ranking, recommendation systems, or bidding/auction systems
• A bias toward simplicity and a track record of shipping work with measurable business outcomes
• Strong cross-functional communication skills and experience collaborating with product, commercial, and engineering teams
• Experience working in fast-moving, high-ownership environments where you can see your impact quickly

This is a staff-level position requiring someone who can operate independently, make strategic technical decisions, and influence direction across a distributed organisation.

How We Work with You

Get A Job.ai partners with exceptional technology companies to connect them with senior engineering talent. When you apply through our platform:

• A recruiter from our team will screen your application and conduct an initial conversation to understand your background and goals
• If there's a strong match, we'll submit your profile to our client for consideration
• We'll coordinate the interview process and provide guidance throughout
• Please do not contact the client directly—all applications must come through Get A Job.ai to be considered

This role is based in London and offers the opportunity to solve genuinely novel problems in advertising technology at significant scale.

Pay

Compensation details will be discussed during the screening process and will be competitive for a staff-level machine learning engineer in the London market.

Equal Opportunity

Get A Job.ai is committed to fostering an inclusive recruitment process. We welcome candidates from all backgrounds regardless of age, gender, ethnicity, disability, sexual orientation, gender identity, socio-economic background, religion, or belief.