Apache Traffic Server™ software is a fast, scalable and extensible HTTP/1.1 compliant caching proxy server. Formerly a commercial product, Yahoo! donated it to the Apache Foundation, and it is now an Apache TLP. Here's a Traffic Server overview.


Important security announcement: All versions of Traffic Server prior to v3.0.4 and v3.1.3 have a vulnerability where a large Host: header can crash the server under certain conditions. Everyone is encouraged to upgrade as soon as possible. For more details, see CVE-2012-0256. New releases addressing this issue are available on the Download page. The latest release is v5.0.0.

Downloads
  • Caching

    Improve your response time, while reducing server load and bandwidth needs by caching and reusing frequently-requested web pages, images, and web service calls.

  • Proxying

    Easily add keep-alive, filter or anonymize content requests, or add load balancing by adding a proxy layer.

  • Fast

    Scales well on modern SMP hardware, handling 10s of thousands of requests per second.

  • Extensible

    APIs to write your own plug-ins to do anything from modifying HTTP headers to handling ESI requests to writing your own cache algorithm.

  • Proven

    Handling over 400TB a day at Yahoo! both as forward and reverse proxies, Apache Traffic Server is battle hardened. Also visit our Customers page (see link above) for some of our corporate users and supporters.

  • Having trouble with builds, configurations or are you getting errors you don't understand? Subscribe to our Users Mailing List or join our #traffic-server channel on irc.freenode.net to get help!

  • Can't get your plugin to work? Get help from developers or start a discussion on our dev discussion list.

  • Report or confirm bugs or try out the latest patches from our Bug Tracker

  • Learn here how to ask good questions, create useful bug reports and how to apply patches.

  • Subscribe and help out on the users Mailing List or simply share your usecase or experience. For (hopefully) speedier responses check out our IRC channel #traffic-server on irc.freenode.net.

  • Impress developers or help others by participating on our dev discussion list or follow the latest development on our commits list.

  • Report issues or bring patches to our Bug Tracker

  • Visit our wiki to see a list of Projects we are currently working on.

  • Learn here how to create patches to the code or the documentation and how to debug Apache Traffic Server..

  • Or just fix a random bug!

  • A low entrance barrier is helping us clean up our code: Fix clang build warnings.

  • June 17, 2014:We are extremely pleased to announce the release of our latest major release, v5.0.0! This has been a year in the making, and includes a number of new features and bug fixes.
  • April 29, 2014:A bug-fix release for v4.2 is now available. Fetch the latest v4.2.1 tarballs from the Downloads section. This is our LTS branch for 4.x.
  • March 19, 2014:A minor release for v4.x is now available. Fetch the latest v4.2.0 builds from the Downloads section. This is our LTS branch for 4.x.
  • December 17, 2013:A bug fix release for v4.x is now available. Fetch the latest v4.1.2 builds from the Downloads section.
  • October 4, 2013:A bug fix release for v4.0.x is now available. Fetch the latest v4.0.2 builds from the Downloads section.
  • August 30, 2013:We are extremely pleased to announce the release of our latest major release, v4.0.1! This has been a year in the making, and includes a number of new features and bug fixes.
  • August 19, 2013: The Apache Traffic Server community welcomes our latest committer, Yunkai Zhang. Welcome!
  • August 16, 2013: Our latest developer release, v3.3.5-dev, is now available from the download page.
  • July 31, 2013: The Apache Traffic Server community is extremely pleased to announce the immediate availability of ATS v3.2.5. It can be downloaded from the normal download page, or via one of the Apache mirrors.
  • June 12, 2013: You can now follow Traffic Server on twitter (@trafficserver) and Google Plus. Also see the link to our new blog above!
  • June 10, 2013: Our latest developer release, v3.3.4-dev, is now available from the download page.
  • April 18, 2013: Our latest developer release, v3.3.2-dev, is now available from the download page.
  • March 14, 2013: Our latest developer release, v3.3.1-dev, is now available from the download page.
  • March 11, 2013: The Apache Traffic Server community welcomes our latest committer, Uri Shachar. Welcome!
  • January 25, 2013: The Apache Traffic Server community is extremely pleased to announce the immediate availability of ATS v3.2.4. It can be downloaded from the normal download page, or via one of the Apache mirrors.
  • November 19, 2012: The Apache Traffic Server community welcomes our latest committer, Bin Chen (chenbin) and Arno Töll (arno). Welcome!
  • September 7, 2012: The Apache Traffic Server 3.3.0-dev is now available on the Apache mirrors.
  • September 6, 2012: The Apache Traffic Server community welcomes our latest committer, Phil Sorber (sorber). Welcome!
  • August 30 , 2012: The Apache Traffic Server community welcomes our latest committer, Otto van der Schaaf (oschaaf). Welcome!
  • June 20, 2012: The Apache Traffic Server community is extremely pleased to announce the immediate availability of ATS v3.2.0. It can be downloaded from the normal download page, or via one of the Apache mirrors.
  • June 15, 2012: The Apache Traffic Server community welcomes our latest committers, Wei Jin (taorui) and Daniel Gruno (Humbedooh). Welcome!
  • June 6, 2012: The Apache Traffic Server v3.0.5 stable, and 3.1.4-unstable are now available on the Apache mirrors.
  • March 21, 2012: The Apache Traffic Server v3.0.4 and v3.1.3-unstable are now available on the Apache mirrors. These releases both address a vulnerability discovered in all previous Apache Traffic Server versions. Users of ATS are encouraged to upgrade to one of the two releases as soon as possible. For more details, see CVE-2012-0256.
  • February 8, 2012: The Apache Traffic Server 3.1.2-unstable is now available on the Apache mirrors.
  • January 27, 2012: The Apache Traffic community welcomes our three new committers: James Peach, Brian Geffon and Bart Wyatt!
  • December 07, 2011: The Apache Traffic Server 3.0.2 is now available on the Apache mirrors.
  • November 18, 2011: The Apache Traffic Server 3.1.1-unstable is now available on the Apache mirrors.
  • August 25, 2011: The Apache Traffic Server 3.1.0-unstable is now available on the Apache mirrors.
  • August 24, 2011: The Apache Traffic Server Project proudly welcomes William Bardwell as a new Committer!
  • August 19, 2011: The Apache Traffic Server Project proudly welcomes Lian Zhang (mohan_zl) as a new Committer!
  • July 19, 2011: The Apache Traffic Server 3.0.1 is now available on the Apache mirrors.
  • June 14, 2011: We are extremely pleased to announce that Traffic Server 3.0.0 is now available on the Apache mirrors.
  • June 13, 2011: The Apache Traffic Server Project proudly welcomes Zhao Yongming as a new Committer. Congratulations!
  • May 30, 2011: Traffic Server 2.1.9-unstable is now available on the Apache mirrors.
  • May 5, 2011: Traffic Server 2.1.8-unstable is now available on the Apache mirrors.
  • March 21, 2011: Traffic Server 2.1.7-unstable is now available on the Apache mirrors.
  • March 3, 2011: Traffic Server 2.1.6-unstable is now available on the Apache mirrors.
  • January 12, 2011: Traffic Server 2.1.5-unstable is now available on the Apache mirrors.
  • November 15, 2010: Traffic Server 2.1.4-unstable is now available on the Apache mirrors.
  • October 25, 2010: Please congratulate Igor Galić for becoming a committer and PMC member. Welcome!
  • September 27, 2010: Traffic Server 2.1.3-unstable is now available on the Apache mirrors and fixes a cache corruption issue in 2.1.2.
  • September 1, 2010: We are pleased to announce that Traffic Server 2.1.2-unstable and the stable 2.0.1 are now available on the Apache mirrors. Both releases improve resilience against DNS poisoning and forging of response packets. The 2.1.2 release fixes a few bugs with 2.1.1 and cleans up several other code areas.
  • July 14, 2010: Please congratulate Theo Schlossnagle for becoming a committer and PMC member. Welcome!
  • June 7, 2010: We are pleased to announce that Traffic Server 2.1.1-unstable is now available on the Apache mirrors. This is an unstable release from the development line so all issues reported will be fixed in the trunk. That said, 2.1.1-unstable brings a completely new, flexible configuration layout, simplifying the build and packaging task for binary distributions; performance improvements on cache for larger(ish) objects; and the HTTP state machine is now 64-bit "clean", allowing for caching and proxying documents larger than 2GB.
  • May 18, 2010: We are pleased to announce that Traffic Server 2.1.0-unstable is now available on the Apache mirrors. This is an unstable release from the development line so all issues reported will be fixed in the trunk. That said, 2.1.0-unstable brings a number of features and performance improvements including support for FreeBSD, MacOSX and Solaris, improved cache seek/write efficiency, 64-bit support, and dramatically reduced miss latency.
  • May 10, 2010: Please congratulate Jason Giedymin for becoming a committer and PMC member. Welcome!
  • May 4, 2010:Apache Traffic Server 2.0.0 was released.
  • April 21, 2010: the Apache Software Foundation Board promoted Traffic Server to a top-level project (TLP).