Mobile-first experience is a digital design and development approach that prioritizes the smallest screens and touch interactions first, then progressively enhances for tablets and desktops. It focuses on core tasks, fast performance, accessible content, and streamlined navigation on mobile, while adapting layouts and controls to each device’s strengths rather than porting the same UI everywhere. Done well, it preserves content and feature parity across devices, improves discoverability, and supports SEO by aligning with mobile-centric usage and indexing. See also responsive design and progressive enhancement (NN/g).