# A role between two rooms · Introduction Nobody agrees on what to call the job. Four people who do it have written down what it is, and they agree on more than they differ. ### The intersection Maggie Appleton, in [A Collection of Design Engineers](https://maggieappleton.com/design-engineers), calls “design engineer” the latest label on a pile that already holds interface designer, UX engineer, and front-of-the-front-end engineer. She keeps it because it names something worth distinguishing: “a person who sits squarely at the intersection of design and engineering, and works to bridge the gap between them.” Such a person can decide how something should work, look, and feel, and has the engineering skill to ship it, iterating between design exploration, research, and live code. ### Defined by output Vercel’s team, in [Design Engineering at Vercel](https://vercel.com/blog/design-engineering-at-vercel), says its **design engineers** (A person who sits at the intersection of design and engineering, able to decide how something should work, look, and feel, and to build it; the definitions in this section are from Maggie Appleton, Vercel, Kathryn Gonzalez, and Jim Nielsen.) “blend aesthetic sensibility with technical skills” so they can understand a problem, then design, build, and ship autonomously. What they care about is not a list of pixels: interactions and affordances, reusable primitives, page speed, cross-browser support, touch and pointer input, user preferences, assistive technology. “There is a lot of work behind the pretty pixels.” There is no handoff. A designer sketches a start and iterates with a design engineer in Figma or code, and animation, keyboard control, and touch are prototyped in the browser because rebuilding them from another medium wastes the effort. ### Three attributes Kathryn Gonzalez built the practice at DoorDash, from first product designer to leading design infrastructure. Her [The Attributes of a Design Engineer](https://www.ryngonzalez.com/blog/the-attributes-of-a-design-engineer) refuses the easy version (“a designer who knows how to sling some React”) and names three attributes: build with significant autonomy, practise and teach great software craft, and elevate the final fidelity of what gets made. A design engineer “loves the craft and the materiality of building software.” The lineage is long: creative technologists, Flash developers, design technologists, UX engineers. Where they cluster Appleton observes that the people she follows come mostly from Vercel, Linear, The Browser Company, and Replit. Several authors in this book have worked at more than one. ### The economic case Jim Nielsen, in [The Case for Design Engineers](https://blog.jim-nielsen.com/2022/the-case-for-design-engineers/), counts the artifacts a responsive design produces when designers and developers work in sequence, up to sixty per iteration, and observes that a design engineer collapses the pile. They hold the medium’s constraints in their head, so they produce one or two artifacts. “There’s no need to explicitly design and document all possible states for whoever is downstream of the designs because they are the ones downstream of the designs.” Read together: the role is ownership of an outcome rather than a slice of a process, fluency in the material rather than a tool, and care for details most people never consciously notice. The book is organised around those details in five parts. **Feel**: [Invisible details](https://learn-ui.com/chapters/invisible-details) and [Motion](https://learn-ui.com/chapters/motion). **Build**: [Components](https://learn-ui.com/chapters/components) and [Craft](https://learn-ui.com/chapters/craft). **Judge**: [Taste](https://learn-ui.com/chapters/taste). **Explain**: [Explaining with interaction](https://learn-ui.com/chapters/explaining) and [Canvases](https://learn-ui.com/chapters/canvases). **Work**: [The career](https://learn-ui.com/chapters/career).