Staff Machine Learning Engineer in London

About Us

Permutive’s mission is to rebuild data in advertising to protect privacy. The open internet needs a sustainable foundation that funds the free & open online experiences we all rely on. Permutive’s data collaboration platform uses edge technology to securely process data where it is and AI to discover signals that drive performance—respecting consumers’ privacy preferences while delivering outcomes for publishers & advertisers.

Our customers include some of the world’s largest media companies and advertisers—including News Corp, Warner Brothers Discovery, Hearst, The Guardian, Sky, State Street, Sonos, and Apple—and we’re backed by leading investors like SoftBank Vision Fund and Y Combinator.

Engineering At Permutive

We’re 30+ engineers working to build an outstanding engineering culture so that everyone who joins has the opportunity and the support to do the best work of their life. Small, autonomous teams are important to us, and we want to empower everyone to make decisions confidently and take ownership of their impact.

We operate at a massive scale: our platform handles more requests each day than there are new tweets and Google searches, and each month we serve more than 2 billion user devices. We combine our patented edge-computing capabilities and low-latency cloud services to deliver real-time customer experiences.

We think applying functional programming techniques like compositionality and type-safety is the best way to build the type of massively distributed system our platform comprises, allowing us to move fast without sacrificing quality.

About the Role

We’re looking for a Staff ML engineer to own optimisation across our platform. You’ll be the domain authority on how we use data to make campaigns perform better — from how audiences are composed and scored, to how inventory is priced and allocated, to how campaigns are tuned over their lifetime.

The scope is broad: campaign optimisation, audience quality modelling, lookalike improvement, and measurement all fall within your remit. You’ll work across teams, identifying which problems to solve, designing the approaches, and owning the models through to production.

This is a hands-on technical leadership role with broad scope and real autonomy. You’ll operate across the full platform, with the freedom to identify the highest-leverage problems and design the approaches to solve them. You’ll shape what we build and have a seat at the table when we make product and strategy decisions.

What you’ll be doing?

• Design and build models for campaign optimisation, working across metrics like CTR, CPA, and ROAS using publisher-side signals (cohort membership, contextual data, engagement) combined with advertiser outcome data.
• Develop approaches to inventory allocation that account for audience quality, placement value, and supply dynamics.
• Own your models end-to-end from conception through production monitoring. You’ll work closely with specialist engineers who integrate models into our high-throughput Scala services, SDKs, and data pipelines — you own the logic, they own the infrastructure, with shared accountability for outcomes.
• Influence product direction by identifying opportunities, framing feasibility, and bringing evidence to roadmap decisions.
• Run experiments and prototypes to validate ideas quickly, then evolve the best ones into production systems.

What you’ll need?

Essential:

• Direct experience with optimisation or bidding systems in programmatic advertising — within a DSP, SSP, ad server, or comparable platform. You understand the mechanics of how campaigns are priced, paced, and optimised in practice.
• Strong applied ML and statistical foundations. You can design, evaluate, and iterate on models — and you know when a heuristic beats a neural network.
• Production ML experience. You’ve built models that run in real systems, not just notebooks. You understand latency, data freshness, feedback loops, and the gap between offline evaluation and online performance.
• Fluency with the programmatic ecosystem — bid requests, win notifications, the signals available at decision time, and the differences between publisher-side and buy-side data.
• Strong communication skills. You can explain your thinking to engineers, product managers, and leadership, and you’re comfortable advocating for a technical direction.

We’d be particularly excited if you have one or more of the below

• Experience with cross-publisher or cross-supply optimisation.
• Familiarity with privacy-constrained environments — cohort-based targeting, clean rooms, working without user-level identifiers.

Why this role?

You’re designing optimisation systems for a platform with a genuinely unusual position — deep publisher-side data, privacy-first architecture, and direct activation through SSPs and ad servers. The modelling problems are novel.

Permutive sits right on the supply so you’ll have access to signals that nobody in the bid stream sees — engagement, content, behavioural patterns from inside the publisher.

Small team, high ownership, direct impact. No layers between your work and the product.

What we’re offering…

We take a structured, objective approach to salary-setting, which is based on marketing information, our compensation strategy, and your experience and capability assessed through our interview process. For a typical candidate who meets our requirements, we pay a base salary of £180,000 - £204,000.

Permutive Benefits

• In this together: As a full-time employee, you’ll become a shareholder with stock options, sharing in our collective success.
• Family Comes First: Primary caregivers receive up to 6 months of fully paid leave and secondary caregivers receive 3 months of fully paid leave to bond with their little ones.
• Your Time, Your Way: Flexible hours let you fit work around your life, whether it’s hitting the gym, meditating, or handling family needs.
• Upgraded Workspace: A £350 budget helps you create the perfect home office setup.
• Recharge & Refocus: Unlimited paid time off (with a minimum of 25 days + public holidays) ensures you get the rest you need.
• Grow with Us: Ongoing training and development opportunities fuel your career aspirations.
• Mental Health Matters: We prioritise your well-being with free access to Spill, our mental health partner.
• Comprehensive Care: Enjoy virtual GP visits, healthcare services, work-life consultations.
• Secure your future: Our pension plan with Penfold helps you secure your financial future (employer contributes 3%, employee contributes 5%).

Work Your Way

Permutive trusts you to manage your time and deliver results. Our hybrid model allows you to choose where you work best, whether in your own productive space or our London (Farringdon) or New York (Union Square) offices. That said, none of us work alone; we are part of a team.

To foster collaboration and connection, teams in these locations come together in person at least once a week and are encouraged to benefit from being in our offices to meet with teams more often. Commercial and customer-facing teams are encouraged to embrace in-person interactions to build lasting relationships with clients and colleagues.

Every Permutive employee gets together in person at the company’s Annual Kick Off for a week in February. Each year’s event promises to be an exciting opportunity for us to come together, reconnect with colleagues, and align on our shared vision for the year ahead.

Diversity, Equity & Inclusion

At Permutive, we’re taking a thoughtful, intersectional, long-term approach to diversity, equity & inclusion. We care deeply about creating an inclusive work environment that allows everyone to flourish, and we are taking continual action to progress in that direction.

We’re committed to hiring people regardless of race, religion, colour, national origin, sex (including pregnancy, childbirth, and related medical conditions), sexual orientation, gender identity, age, neurodiversity status, disability status, or otherwise.