Senior Design Engineer

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.

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