Ancient Web: zlib Kept 1995 Compression Source Files on a Living Homepage

Part of the Ancient Web Collection.

A humble compression library from 1995 is still receiving updates. Better yet, its homepage still looks like something its original users might recognize.

Visit the zlib homepage.

The front page identifies Jean-loup Gailly as the author of the compression code and Mark Adler as the author of the decompression code, with the webpage originally created by Greg Roelofs. Its heading combines technical seriousness with a deliberately playful claim about being free, compact and unencumbered by patents.

The footer dates the website's copyright from 1996, and the software itself from 1995. The main page was still being updated in February 2026, announcing zlib version 1.3.2 and enumerating security fixes, build changes and compatibility work. The site qualifies because its own old archives and documentation remain part of the working project, not because its current maintenance has stopped.

The archive contains actual software fossils

The fossil directory goes back to source archives such as zlib 0.71 and 0.8 from April 1995. Later versions, including 1996 releases, remain listed by filename, size and modification date. The directory makes it possible to trace the early library through successive distributions rather than merely reading a historical description.

The FAQ is another time capsule. Its very first question asks whether zlib is Y2K-compliant. Elsewhere it discusses Visual Basic, Delphi, Windows DLLs, Solaris shared libraries, endianness and the perennial confusion between zlib's compressed stream and a full ZIP archive.

The homepage links directly to RFC 1950, RFC 1951 and RFC 1952, which standardized the zlib, DEFLATE and gzip formats in May 1996. It also connects zlib to Java's early compression classes, PNG and innumerable software environments.

Importantly, the FAQ does not pretend every older distribution is safe to install. Current projects should use maintained versions and check security notices, not blindly run an archived library because it is historic.

Where a modern software release page might hide previous versions behind a short dropdown, zlib still offers the old reference links, technical notes and unglamorous source tarballs in plain sight. It is a reminder that open standards endure partly because somebody keeps the documentation beside the code.

Explore the dated fossil releases and old FAQs.

Part of the Ancient Web Collection.