Design and code,
one discipline.

Design engineering is what happens when one person owns both the mockup and the code that ships it. A design engineer thinks in systems, things like spacing scales, motion curves and state machines, and then writes the actual UI instead of handing a picture of it to someone else.

The discipline sits where Figma ends and the browser begins. That territory used to belong to nobody. Designers shipped files, engineers shipped features, and everything in between, the hover states, the easing, the way a dialog settles into place, got decided by whoever happened to be holding the ticket.

The title is new but the work is not. People have been doing it under names like UX engineering, creative development and prototyping for years, usually without getting noticed or paid for it. Calling it design engineering just made the job visible enough to hire for.

Most UI debt is translation debt. A design specifies 24px of space and a certain feel for how a menu should open. Somewhere in the handoff that becomes mt-4 and a default tween. One screen survives it. A whole product does not.

The further a decision travels from the person who made it, the more of the decision gets lost. Design engineering shortens that distance to zero. The person who chose the easing curve is the person who writes the transition, so nothing gets approximated on the way to production.

There is also a speed argument. A prototype built in real code answers questions a static mockup cannot: does this feel right at 60fps, does it hold up with real data, does the motion survive contact with actual content. Teams that prototype this way learn faster because they test the real thing.

Every component in this library is designed and engineered together. States, spacing, radii and motion are tuned by hand, then frozen into the component, so the decisions travel with the code when you copy it into your app.

Because the behavior is baked in, you start from an intentional baseline instead of a default one. You can still override anything, but you are editing something that was already designed to work, not filling in gaps that were never decided.

That is the whole promise: components that respect both sides of the craft, the design system they came from and the engineering constraints they run under, because the same pair of hands built both sides.