misa77 is an LZ-based codec targeting the write-once, read-many niche with SOTA decompression throughput in its ratio class. It achieves 1.5-3x faster decompression than LZ4 on x86 and ARM while offering comparable ratios to LZ4 at high effort levels. The tradeoff is slow compression and no entropy backend.

Benchmarks on Intel i7-14650 HX show misa77 -0 decoding at 5219 MB/s (42.64% ratio) versus LZ4 at 2505 MB/s (47.59% ratio). On enwik8, misa77 -0 reaches 4802 MB/s decode. The codec uses constant memory (<=5 MB compression, 0 MB decompression) and features two effort levels: -0 for maximum decode speed, -1 (default) for better ratios.

misa77 requires C++20, CMake >= 3.20, and a little-endian 64-bit system. The CLI operates on single files with commands for compress, decompress, and parameter suggestion. Experimental modes like --adaptive and --yolo optimize for decode speed. The format may change in v0.x.y and is not hardened against invalid input. Licensed under MIT.