User Experience (UX) design is the process of enhancing user satisfaction by improving the usability & accessibility provided in the interaction between the user and the product.
Developer Experience (DevX or DX) is the equivalent to User Experience (UX) when the user of the software or system is a developer. DX describes the experience developers have when they use your product, be it client libraries, SDKs, frameworks, open source code, tools, API, technology or service.
When creating systems for user facing software, user experience is more important than developer experience. In a large number of cases improving developer experience is the best way to improve user experience, so rather than being in conflict these goals are often in congruence.