Principal Product Experience Engineer

Polygon.io, Inc; Northern (KY); Hybrid; USD 140,000 - 210,000; Full time

Benefits offered by this job

Comprehensive medical plans

401(k)

Unlimited time off

Job summary

Massive is seeking a Principal Product Experience Engineer to help define how product development works in an AI-first world. This cross-functional role combines frontend engineering, product judgment, and UX sensibility, with AI as a core part of thinking, building, and iterating.

You will work across problem framing, experience design, and implementation to create new user experiences end to end, owning initiatives from hypothesis to shipped experiences, and collaborating with product, design,

Qualifications

• Proven ability to design and implement complex, high-quality interfaces with excellent interaction and polish.
• Strong architectural instincts for frontend systems that scale in complexity without becoming brittle.
• Comfort owning the frontend end to end, from initial prototype to long-lived production code.
• Strong product judgment with the ability to frame work as hypotheses and evaluate outcomes using real signals.
• Strong instincts around scope, sequencing, and tradeoffs.
• Practical UX sensibility—you can execute thoughtful UX without relying entirely on mocks.
• AI-native workflow with meaningful use of AI tools in day-to-day work.

Responsibilities

• Own product initiatives from hypothesis to shipped experience, with clear intent and validation signals.
• Use AI extensively to accelerate prototyping, implementation, iteration, and exploration of UX ideas.
• Design and build complete user experiences, from interaction models to polished, production-ready frontend code.
• Start with small bets and ship early versions to learn and refine.
• Iterate based on real-world usage and feedback, deciding when to continue, adjust, or stop.
• Partner with product, design, and QA to clarify problems, define quality bars, and maintain coherence without heavy handoffs.

Skills

Frontend engineering

UX design sensibility

Product judgment

AI-native workflow

Ownership

Cross-functional collaboration

Prototype to production

Analytics mindset

Problem framing

Execution under uncertainty

Tools

PostHog

Amplitude

AI tools

Job description

Careers / Principal Product Experience Engineer

We are looking for a Product Engineer to help define how product development works in an AI-first world.

This is a cross-functional role for someone who combines exceptional frontend engineering skill, strong product judgment, and a solid UX sensibility, and who uses AI as a core part of how they think, build, and iterate.

You will work across problem framing, experience design, and implementation to create new user experiences end to end. Rather than moving work through traditional product, design, and engineering phases, you will operate with a high degree of ownership while collaborating closely with product, design, and QA to shape intent, quality, and direction.

This role is about turning ideas into real, testable experiences quickly and learning from what happens next.

Responsibilities

• Own product initiatives from hypothesis to shipped experience, with clear intent and validation signals.
• Use AI extensively to accelerate prototyping, implementation, iteration, and exploration of UX ideas.
• Design and build complete user experiences, from interaction models to polished, production-ready frontend code.
• Start with small, explicit bets and ship early versions to learn and refine rather than over-planning upfront.
• Iterate based on real-world usage and feedback, deciding when to continue, adjust, or stop.
• Partner with product, design, and QA to clarify problems, define quality bars, and maintain coherence without heavy handoffs or queues.

Skills & Qualifications

• Proven ability to design and implement complex, high-quality interfaces with excellent interaction and polish.
• Strong architectural instincts for frontend systems that scale in complexity without becoming brittle.
• Comfort owning the frontend end to end, from initial prototype to long-lived production code.
• Strong product judgment with the ability to frame work as hypotheses and evaluate outcomes using real signals.
• Strong instincts around scope, sequencing, and tradeoffs.
• Practical UX sensibility—you can execute thoughtful UX without relying entirely on mocks.
• AI-native workflow where you already use AI tools meaningfully in your day-to-day work and treat AI as leverage for thinking and building.
• Ownership and follow-through—comfortable carrying work across definition, build, release, and evaluation.
• Experience using product analytics tools such as PostHog, Amplitude, or similar to define signals, evaluate bets, and guide iteration.
• Founder mentality with comfort making decisions under uncertainty and taking responsibility for outcomes.
• Experience working in fast-moving environments where direction is shaped through execution rather than detailed plans.
• Background in financial markets, market data, or data-intensive products is a plus.

About Massive

At Massive we are on a mission to help developers build the future of fintech. We are committed to democratizing access to the world's financial market data and enabling developers to build the future of fintech. Join us and be part of a team that is revolutionizing the way we interact with money and value.

Massive is an equal opportunity employer and complies with all applicable federal, state, and local fair employment practices laws. We strictly prohibit and do not tolerate harassment or discrimination against employees, applicants, or any other covered persons because of race, color, religion, creed, national origin or ancestry, ethnicity, sex, gender, gender identity, age, physical or mental disability, citizenship, sexual orientation, past, current or prospective service in the uniformed services. To request a reasonable accommodation, please email [e-mail] .

• Benefits for full time offers from Massive include, but are not limited to, comprehensive medical plans, 401(k), and unlimited time off.

When determining a candidate’s compensation, we consider a number of factors including skillset, experience, job scope, and current market data.

Before submitting your application, please take a minute to review our Applicant Privacy Notice , which describes the data we collect, why we collect it, and how we use it. By submitting your application, you consent to our Applicant Privacy Notice .

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