Principal, User Experience

Newton Research•Needham, MA

10h•$180,000 - $220,000•Remote

About The Position

Brands and agencies spend billions a year on media and still struggle to answer two questions: what is actually working, and what should we do next? Their tools don't help much. Mediaocean is the system of record for what they bought. The DSP is the system of action for how it ran. Nothing owns the why — the decision itself. That is what Newton is building: the system of decision for media investment, and increasingly the system that acts on those decisions. A causal engine explains what drove the outcome, agents turn that into a plan, and governed action carries it back into the platforms where the money is spent. Today that means decision intelligence for humans. Next it means decisions that execute with approval, and eventually within policy the customer sets. Design is what makes that real. Our users are media planners, buyers, analysts, and CMOs, not data scientists, and they have to trust a recommendation enough to move real budget behind it — and then hand over more of the doing. The conventions for that don't exist yet. Nobody has settled how a media team teaches an agent the way they work, directs a dozen of them at once, or corrects one in a way that makes the whole system smarter next cycle. Whoever defines it for this industry sets the pattern others copy. As Principal, User Experience, you will own that problem end to end. You will set the design direction for the entire Newton platform and be the person who makes agentic software feel obvious to people who have spent their careers in spreadsheets and dashboards. This is a hands-on role first — you will be in Figma and in prototypes every week — and a leadership role second, growing and running the design function as the company scales. You will be our most senior design voice, working directly with the founders, product, engineering, and data science. You will define what good looks like, and then build the team that delivers it.

Requirements

10+ years designing digital products, with deep experience in complex B2B or enterprise SaaS
Demonstrated ability to lead design for a full product surface, not just features — you have owned the whole thing
Experience leading or mentoring other designers, and the appetite to build a team from a small base
A portfolio that shows data-dense, workflow-heavy interfaces made genuinely usable; data visualization craft is a strong plus
Fluency with modern design and prototyping tools, and comfort prototyping in code or with AI tooling to communicate intent fast
Track record of shipping alongside engineering in a fast-moving environment, with a real design system behind you
Excellent communication and storytelling — you can hold your own with founders, engineers, data scientists, and customer executives

Nice To Haves

Adtech, martech, marketing analytics, or other quantitative domain experience is a strong plus
A real point of view on AI-native product design — how people delegate work to agents, follow what they did, and decide when to trust them

Responsibilities

Own and evolve the agent-to-human interface for media: how a planner teaches an agent the way they work, directs several agents at once across a campaign, and corrects their output in a way that makes the system better at that account each cycle
Own the end-to-end user experience across Newton's platform — planning, buying, measurement, and the agentic workflows that connect them
Make complex analytical output — causal models, incrementality results, scenario plans, optimization recommendations — clear and defensible to non-technical decision makers
Design the approval and control experience for governed action: what an agent is allowed to execute, what a human signs off on, and how a customer sets and trusts those limits
Stay hands-on: wireframes, high-fidelity design, interactive prototypes, and close pairing with engineering through implementation
Build and maintain Newton's design system and front-end design standards so the platform stays coherent as products and teams multiply
Run lightweight research and usability work with customers at brands, agencies, publishers, and platforms; turn what you learn into design decisions and product direction
Partner with product and data science to pressure-test concepts early, and with sales and marketing on demos and narrative when design is doing the selling
Hire, mentor, and lead a growing design team, establishing critique, process, and quality bars that scale beyond you
Bring a point of view on where the interface is heading as AI reshapes enterprise software, and push the company toward it