Senior Design Engineer

Product.ai; Los Angeles (CA); Hybrid; USD 350,000 - 450,000; Full time

Benefits offered by this job

Relocation support

PIU ownership

Hybrid schedule

Job summary

Product.ai seeks a senior design engineer to own and ship end-to-end consumer interfaces across /shop, Verification Checker and SimplyCodes in production React/TypeScript. You will co-own the design system, tokens, motion physics, and rules in code, ensuring precise, trustworthy interfaces that render evidence beside verdicts and support streaming state transitions.

You will collaborate directly with our Founding Designer and founder, shaping the visual, interaction, and motion bar, and

Qualifications

• Real human-computer interaction background.
• Portfolio of shipped interfaces with design taste.
• Production-quality React/TypeScript/CSS.
• Fluent in Figma; strong motion and state design.
• Experience using AI design tools as multipliers.

Responsibilities

• Co-own visual, interaction, and motion bar across surfaces; take directions from sketch to shipped production code with zero handoff.
• Own the canonical master components, tokens, motion physics, and rules in the /shop Design Record.
• Develop live production interfaces end to end for the Verification Checker, conversational shopping assistant, and its evidence side panel.
• Polish motion physics layer: timing, spacing, typography and micro-interactions to convey trust.
• Draft and own the seat charter within the first quarter with measurable machine-checkable proof of working.

Skills

HCI background

Shipped interfaces

React

TypeScript

Figma

Tools

React

TypeScript

CSS

Figma

Job description

You draw the interface and ship it in the same session, on the surfaces where a person asks an AI what’s actually true about a purchase. Partnering directly with our Founding Designer and the founder to set and raise the consumer design bar, you own the /shop Design Record components, motion physics, and live production interfaces end to end.

Product.ai (product.ai) is the verification layer for commerce: when a person or an AI agent needs to know what’s actually true about a purchase, we answer with proof. SimplyCodes (simplycodes.com) is the first proof at scale, the code verification service, at ~$22M a year in revenue. Profitable. Founder-owned since 2009, bootstrapped, no outside investors, no board. Fewer than twenty operators.

Why This Role Exists

We are shipping several consumer surfaces at once: our /shop Verification Checker (where a shopper pastes what an AI, an article, a brand page, or a friend told them to buy, and we grade the claims inside it across five verification states — free to consumers to build habit and trust while AI shopping agents pay per call for verified commerce truth), our conversational shopping assistant that answers with proof beside the answer, and the SimplyCodes pages and browser extension that millions of shoppers use every day.

We need a senior builder who takes consumer interfaces from design exploration to live production code with zero handoff, and who co-owns the /shop Design Record and design system in code. You are senior: you’ve shipped interfaces people love, you have a real human-computer interaction background, and your portfolio shows taste a stranger can see immediately. You partner directly with our Founding Designer and the founder to set and raise the consumer design bar across every surface.

The part that makes this different from a traditional frontend or design seat: our design system is executable law, not a guideline. Its tokens, components, and motion physics in the /shop Design Record are read directly by the coding agents that generate our interfaces, so precision in the design system governs the entire product.

The System You’ll Need to Model

• The Verification Checker and a conversational surface that shows its work. Whether a shopper pastes a recommendation into the Verification Checker or asks a shopping question in chat, the interface grades claims across five verification states, streams citations, and lets a person inspect the evidence beside the verdict without losing the thread. Streaming state, interruption, and motion physics are design decisions, not plumbing.
• Decision-shaped interfaces. The unit of every surface here is a verified answer and how sure we are of it. Confidence has to render as credible, never oversold and never buried, and that’s motion, state, and typography doing trust work.
• The /shop Design Record and a design system agents build inside. Master tokens, a canonical component catalog, and usage rules precise enough that coding agents generating a screen stay within the bar.
• Prototypes that are the real thing. The design-to-engineering handoff is gone here. A direction is explored as a working prototype in a design tool and in production React/TypeScript in the same session, and the winners ship live.
• Cortex, the shared AI brain the company runs on. You work inside it daily, directing coding agents as force multipliers the way our founder does, and since August any operator here can change the rules the company runs on, live, without waiting on founder approval.

If reading that energizes you, keep going. If it feels overwhelming or underspecified, this isn’t the right fit.

What You Will Own

• Partnering directly with our Founding Designer and the founder to set and raise the consumer design bar. You co-own the visual, interaction, and motion bar across our consumer surfaces — taking directions from sketch or interactive rig to shipped production code with zero handoff.

• The /shop Design Record and design system in code. You own the canonical master components, tokens, motion physics, and rules that govern our consumer interfaces and coding agents across /shop, the Verification Checker, SimplyCodes, and the browser extension.

• Live production interfaces, end to end. Design and code for the Verification Checker, the conversational shopping assistant, and its evidence side panel: how a verdict renders across five verification states, how proof opens beside it, how streaming and state transitions feel in the hand, and how our frontend architecture composes them cleanly in React and TypeScript.

• The polish and motion physics layer. Motion, state, spacing, typography, and micro-interactions: the thousand small decisions that make a trust interface feel unmistakable.

• Your seat charter. Within your first quarter you co-sign a charter for this seat. It names one machine-checkable number that proves the seat is working, and a high-ownership partnership model with our Founding Designer and the founder.

The craft you must already own: a real human-computer interaction background, not a gloss of design vocabulary; a very strong design eye, proven by a live portfolio of shipped work; building interfaces in React, TypeScript, and CSS at production quality; fluency in Figma; motion physics and state designed on purpose; and AI coding and design tools as force multipliers you verify by hand.

Comparable experience: a senior design engineer or frontend engineer with real design taste and an HCI background, a principal/senior product designer who ships their own production React code, or someone who designed and shipped a consumer product end to end.

Who You Are

How you think. You see a screen as a system: what state it’s in, what it’s telling the person, and where friction hides. You think about the person on the other side of the screen the way a human-computer interaction education teaches: what they’re trying to decide, what they can perceive, and how layout, typography, and motion earn their trust.

How you work. A design tool, a coding agent, and a browser open together, most of the day. You use AI tools as force multipliers for design and code, and you verify every detail because you can build it by hand.

What you’ve probably built. Interfaces real people used, that you can show live and say what you decided and why: a product people trusted with a decision, a design system other engineers built inside, a prototype that became the shipped production surface. The portfolio is more important than the resume.

Who this isn’t for. This is wrong if you want to be handed finished designs to implement, or finished code to style; here both halves are yours end to end. It’s wrong if you want a traditional design-management bureaucracy instead of building directly alongside our Founding Designer and the founder. You’ll be happiest here if you want your work in front of real shoppers every day and you’d rather ship the live interface than present a slide deck.

How We Hire

We don’t run traditional design or engineering interviews.

1. Async video screen (or Fast-Track Portfolio/GitHub review). About 15 minutes, on your own time, replacing the recruiter screen — or, if you have a standout live portfolio of shipped interactive work and GitHub repos.

2. Calls with company stakeholders. Short conversations with the people you’d build beside, including our Founding Designer.

3. Conversation with the founder. How you see a screen, how you use your tools, and what you’d elevate first across the Verification Checker and /shop.

4. Paid work trial (PRJ-75). A paid real-work trial in our environment: taking a live /shop Verification Checker or consumer interface from direction to shipped production React/CSS inside the /shop Design Record. We look for visual taste, motion physics, how you use AI tools as force multipliers, and how we collaborate together.

We hire on the work and the reasoning, not the pedigree.

Compensation & Ownership

Total first-year comp: $350,000 to $450,000 (base + performance-based PIU ownership and profit-share program). Base: $220,000 to $280,000, top of market for senior design engineering.

Product.ai is a profitable, founder-owned company generating ~$22M a year in revenue with zero venture debt. Beyond base salary, senior operators participate in our Profit Interest Unit (PIU) ownership and profit-share program ($0 strike price units that share directly in annual free-cash-flow distributions and annual company tender liquidity, earned on performance milestones). Grants are performance-based and earned after joining, never day-one vesting, with formal terms governed by the plan documents at the offer stage; 100% family premium coverage; and an effectively unlimited token budget, steered by return, never capped.

Based in Santa Monica, Los Angeles, on our high-trust hybrid rhythm: four focused in-office half-days together (Monday, Tuesday, Thursday, Friday from 9am to 2pm), with Wednesdays open for deep work and afternoons yours to work from wherever you do your best work. Relocation support available for the right builder.