Shrink cold text & logs below zstd and xz — and decode byte-for-byte on any machine.
FP-CODEC is a classical context-mixing coder, frequency-count context models, a single logistic mixer and an arithmetic coder with lpaq-style APM/SSE refinement. On enwik8 it hits ≈2.03 bits/char, below zstd-19 (≈2.29) and lzma-9e (≈2.23), byte-exact lossless, and because it is integer-only it is bit-identical across x86-64, wasm32 and ARM64 by construction.
Bit-identical across platforms
The coder is integer-only, no float, no fused-multiply-add, no transcendentals, so the same source compiled to native, wasm32 and ARM64 produces byte-identical compressed streams. Verified: 0 divergent bits over 10⁶ symbols on text, real logs and random data; SHA-256 of the stream matches on every arch.
Beats zstd-19 AND lzma-9e on text
Frequency-count context models feed a single logistic mixer and an arithmetic coder, with lpaq-style APM/SSE lookup-table refinement. On enwik8 that lands ≈2.03 bits/char, below zstd-19's ≈2.29 and lzma-9e's ≈2.23, byte-exact lossless. It also wins materially on Apache / Linux / SSH / HDFS / BGL system logs.
Verified & never-worse
Every archive carries a SHA-256 verified-lossless trailer, and a never-worse fallback: if context-mixing does not win, FP-CODEC delegates to xz / zstd / stored. So the output is never larger than the baseline and is provably the exact original bytes.
Tiny, portable decoder
No model files, no tables to ship, the decoder is the same small integer-only kernel that made the archive. An optional tiny domain-matched prior warms the small-file and log tier without changing the determinism guarantee.
One small command surface.
Compress, decompress and verify, the decoder is the same integer-only kernel that made the archive, so a file made anywhere decodes byte-exact everywhere.
# compress a cold text / log archive to a verified deterministic stream at1 fpcodec c access.log access.log.at1 # byte-exact, integrity-sealed, never-worse at1 fpcodec c corpus.txt corpus.txt.at1 --prior logs # optional tiny domain-matched prior at1 fpcodec d access.log.at1 access.log # exact original bytes, on any platform at1 fpcodec verify access.log.at1 # -> integrity: PASS (SHA-256 matches original)
Top-tier ratio, and the only one you can trust across machines
Dedicated research coders (paq / cmix) can push raw text ratio a little further, that's not the claim. FP-CODEC is the one that pairs a top-tier text ratio with cross-platform bit-identical determinism, a verified-lossless trailer, and a never-worse fallback. paq/cmix are neither deterministic across platforms nor verified.
| Codec | enwik8 bits/char | Cross-platform bit-identical | Verified lossless | Never- worse |
|---|---|---|---|---|
zstd-19 fast general codec, great speed, but gives up ~11% on text and makes no cross-platform-determinism or verification guarantee | ≈2.29 | in practice | ||
lzma-9e (xz) strong general codec, still ~9% behind on enwik8, no verified-lossless trailer, no by-construction determinism | ≈2.23 | in practice | ||
generic context-mixing (paq / cmix) top raw text ratios, but float-based mixing is NOT bit-identical across platforms, and ships no integrity trailer or fallback | ≈1.8 | |||
FP-CODEC top-tier text ratio AND integer-only bit-identical determinism, SHA-256 verified, never worse than xz/zstd | ≈2.03 |
Cold text and log archives, enwik-class corpora, Apache / Linux / SSH / HDFS / BGL system logs, that you store forever and decode rarely, and that must decode byte-identical on any machine. Maximum ratio plus a portable determinism guarantee is exactly the trade this tier wants.
It is a context-mixing coder, so it is slower than zstd, this is a cold-archive tier, not a hot-path general codec. If you need high-throughput compression, reach for zstd; if you need queryable typed data, reach for format-aware columnar or ATLAS. We say so plainly.
Built for
Long-lived text & log archives · compliance and audit stores that must decode byte-identical years later · any cold tier where you store forever, decode rarely, and need one compressed artifact that is provably the original on every platform.
Decoding and verifying an FP-CODEC archive is always free and needs no account; encoding is metered against a connected account.