Senior Product Designer & AI UI Prototyper

Mercor; Pennsauken Township (NJ); On-site; USD 120,000 - 160,000; Full time

Job summary

Cincinnatus LLC is seeking senior product designers and design-minded engineers to shape UI/UX for an AI lab, building high-quality prototypes in code or with AI tools. You will work directly with researchers to define what great design looks like for web and games, and you will explain why one approach works better than another.

This is a full-time W-2 role with Cincinnatus LLC, offering placement at a leading AI lab as part of their extended workforce and under standard employment terms.

Qualifications

• 7+ years of experience as a product designer, design lead, design engineer, or creative front-end engineer at a product- or design-led company or top design agency.
• Hands-on prototyping skills: you build working web prototypes yourself, in code or with AI-native tools.
• A strong grounding in user-centered design, interaction design and rapid prototyping.
• Senior-level design judgment, and the confidence to set direction and explain clearly why a design works.
• Ability to engage reliably for 40 hours/week during weekdays.
• Clear written communication and the ability to give precise, constructive design feedback.
• Nice to have: motion/animation or 3D/WebGL, and game design experience in 2D or 3D.

Responsibilities

• Partner with AI researchers to identify best-in-class UI and UX patterns, and turn them into clear principles and rubrics.
• Build polished, interactive web prototypes in code or with AI-native tools that showcase strong design patterns.
• Review AI-generated interfaces and prototypes, and give specific, actionable written feedback.
• Explore a wide range of visual styles, frameworks and animation approaches across product categories.
• Collaborate with designers and researchers to keep standards consistent and raise quality.

Skills

Prototyping

Frontend tech

User-centered design

Design leadership

Communication

40h/week

Tools

Cursor

v0

Lovable

Bolt

Framer

Job description

Cincinnatus LLC is seeking senior product designers and design-minded engineers to shape UI/UX for an AI lab, building high-quality prototypes in code or with AI tools. You will work directly with researchers to define what great design looks like for web and games, and you will explain why one approach works better than another.

This is a full-time W-2 role with Cincinnatus LLC, offering placement at a leading AI lab as part of their extended workforce and under standard employment terms.