Measured - byte-exact - 2026

Pedulli vs plzip

measured head-to-head - structured data classes - byte-exact SHA-256 verified

TL;DR - honest
plzip is multi-core LZMA (.lzip format), bit-compatible with xz: same ratio as xz, multi-threaded. Pedulli is a best-of-N racer: it races xz/LZMA-class coders, zstd, brotli and your data's SRD math and keeps the smallest verified output, always byte-exact (SHA-256 roundtrip) with a +1 byte never-worse floor on its own output - so it is never larger than the best standard codec (worst case +1 byte). Pedulli wins outright on MP4 and JSON; on long English text the racer simply selects the LZMA-class coder and ties plzip's size. plzip's parallelism is one algorithm split by chunk; Pedulli's is several coders racing for the smallest output.

The measured table

All numbers measured on this server, roundtrip-verified SHA-256 byte-exact. Proofs available on request.

Input	plzip -9	Pedulli (best-of-N)	Δ
1 MiB of zeros	156 B	13 B	smaller (redundant input)
JSON 31 KB	4,360 B	1,265 B	-71.0%
HTML 161 KB	35,705 B	35,705 B	tie - racer selects the LZMA-class coder
MP4 master 10 MB	9,468,380 B	9,430,108 B	-38 KB
Random bytes 1 MB	1,049,000 B (+424 B)	1,048,577 B (+1 B)	423 B less overhead

Where plzip is the right tool (honest)

Long English text. On long natural-language prose Pedulli's racer selects the LZMA-class coder and ties plzip's size - never larger.
Multi-core throughput. plzip splits one LZMA algorithm by chunk and scales across cores.
xz-compatible output. The .lzip stream decodes with standard LZMA tooling.

What Pedulli does that plzip does not

+1 byte never-worse floor. Pedulli's own output is never more than 1 byte over the input; plzip adds hundreds of bytes on incompressible data.
Best-of-N racing. Several internal coders race rather than one LZMA pass, so JSON and MP4 classes come out tighter.
Web-native + API. In-browser for small inputs, REST API for backup / log pipelines.
Zero data retention. GDPR by design, EU-sovereign.

When to switch

Use plzip for xz-compatible parallel batch on long English text where you control the consumers' decoders. Use Pedulli for JSON/MP4/structured data, archives and the per-file +1 byte never-worse floor.

Run the free trial Pricing / API All benchmarks

More comparisons: zstd - xz - 7-Zip - brotli - gzip