Lean UX is an approach to UX design that emphasizes validating designs with customers early and iterating quickly based on feedback, rather than spending a long time documenting specifications. It is inspired by Lean Startup and Agile development methods. The goal is to surface the true nature of the user experience faster and with less emphasis on traditional deliverables. Lean UX advocates rapid prototyping of key assumptions to get customer feedback to evolve the design rapidly.