SmartPack is a lossless archiver built entirely with Python’s standard library. It adapts compression per block, skips incompressible data, deduplicates repeated blocks, optimizes zero-filled data, and verifies integrity with SHA-256. In my first benchmark, 64 MB of duplicate-heavy data became 8 MB vs 37 MB with xz, while mixed-data compression came within ~0.2% of xz’s size at about 3× the packing speed. No third-party dependencies.