Stop decompressing entire archives to get one file — introducing ARCX

Most archive formats make a simple task unnecessarily expensive: you need one file, so you download and decompress everything. I built ARCX, a compressed archive format designed to fix that. ARCX combines cross-file compression (like tar+zstd) with indexed random access (like zip), so you can retrieve a single file from a large archive in milliseconds without decompressing the rest. Try it GitHub: https://github.com/getarcx/arcx Install: cargo install arcx Benchmark results Across 5 real-world datasets: ~7ms to retrieve a file from a ~200MB archive up to 200x less data read vs tar+zstd compression within ~3% of tar+zstd Example: Dataset ARCX Bytes Read TAR+ZSTD Bytes Read Reduction Python ML 326 KB 63.1 MB 198x less Build Artifacts 714 KB 140.4 MB 202x less Why this matters Modern systems don't need entire archives. They need one file, immediately. This shows up in: CI/CD pipelines (artifacts) cloud storage (partial retrieval) large codebases package registries ARCX reduces archive acc