NFHS Digital represents a significant modernization effort in sports officiating tools, delivering the National Federation of State High School Associations' complete rule publications through a mobile platform. Developed by RefReps, the app consolidates rule books, case books, and manuals for 18 sports into a unified digital library, eliminating the traditional dependency on physical publications during games and training sessions. The core functionality centers around its comprehensive digital library, where users can purchase and access sport-specific publications. The search functionality enables rapid rule lookup through keyword queries, while annotation tools allow highlighting, bookmarking, and note-taking directly within documents. The platform supports offline access to purchased materials, addressing connectivity concerns at remote game locations. Organization features include categorization by sport type and the ability to maintain multiple active publications simultaneously. User experience demonstrates thoughtful design for field use, with responsive navigation and legible text presentation optimized for mobile screens. The interface prioritizes quick access to frequently referenced rules while maintaining full document structure. Real-world usage patterns show officials primarily utilizing the app during game preparation, in-game rule verification, and post-game review scenarios, with particular value in time-sensitive situations where physical book consultation would be impractical. User feedback trends reveal strong approval among sports officials, with multiple five-star reviews praising the app's practicality. ZebraStripes52 noted on July 16, 2025 that 'All your rule books right on your phone, super easy to search and bookmark' while Ref Guy 1983 described it as 'an incredible upgrade over previous iterations' on the same date. EI Guap0's August 13, 2025 review highlighted successful download functionality for both casebooks and rule books after initial access issues. The app demonstrates clear strengths in convenience and functionality but faces challenges reflected in its moderate 2.17 rating, suggesting possible technical issues not represented in the provided reviews. The digital transition addresses physical book limitations but depends on device reliability and battery life. Ideal for high school sports officials requiring rapid rule reference, though potential users should verify current stability given the overall rating discrepancy with provided reviews.