greenbytes was founded in June 2000 as consulting and software development company with a heavy bias on technologies driving the Net.

Open Source

In 2015 we developed the implementation of the HTTP/2 protocol for the famous Apache HTTP Server, which is used in about half of the web sites on our planet. Initially sponsored by the GSMA, the implementation has been donated to the Apache Software Foundation and become part of the core product.

As a member of the Apache httpd project committee (PMC) we continue to work on improvements and features, especially in the exciting area of HTTP/2 and web performance.


During the last years we have been very active in various working groups in the "Applications and Real-Time" of the Internet Engineering Task Force (IETF): (→WebDAV )

  • The HTTP Working Group, which works both on revising existing documents (such as RFC 2616 and it's successors RFCs 7230, 7231, 7232, 7233, 7234, and 7235), and defining new extensions (such as HTTP/2). For the former, Greenbytes supports these tasks heavily by contributing one of the editors. We also worked on many extension specifications, such as RFC 6266 ("Use of the Content-Disposition Header Field in the Hypertext Transfer Protocol (HTTP)"), RFC 7538 ("The Hypertext Transfer Protocol Status Code 308 (Permanent Redirect)"), RFC 7615 ("HTTP Authentication-Info and Proxy-Authentication-Info Response Header Fields"), RFC 7694 ("Hypertext Transfer Protocol (HTTP) Client-Initiated Content-Encoding"), RFC 7838 ("HTTP Alternative Services"), and RFC 8187 ("Indicating Character Encoding and Language for HTTP Header Field Parameters" - fwiw the first RFC published in recent years using non-ASCII characters!).
  • The HTTP Auth Working Group, which worked both on new and existing HTTP authentication schemes. We contributed in updating the Basic Authentication Scheme, now RFC 7617, and in reviewing work by others in this group.
  • The WebDAV Working Group, which worked on several extensions to HTTP supporting distributed authoring of Web resources. We contributed to most of the specifications, and participated as authors on many of them. Nowadays, WebDAV clients are implemented in all modern operation systems, and few document management systems ship without WebDAV support.
  • The Atom Working Group, which specified both a robust replacement for the ambiguously defined RSS format, and an HTTP based authoring protocol for feeds. In the meantime, both specifications are used in many unforeseen places, which usually is an indication of smart protocol design.

Finally, Greenbytes provides an XSLT-based formatter for the IETF RFC XML dialect: see RFC 7749 for the specification, and Transforming RFC7749-formatted XML through XSLT for the implementation.

Document Management

Our work in the Document Management space has also led us into other standardization efforts, such as the W3C HTML5 Working Group, the JSR-283 (Java Content Repository) Expert Group, and the OASIS Content Management Interoperability Services (CMIS) Technical Committee. If you're looking for experts in these areas, do not look further!

This expertise has been applied successfully into our customers' products and we took experience from those projects back into the standardization work. It is our belief that this way of working will generate the best standards and interoperable, excellent applications. (→customers )