Various Continuous Integration monitoring/reporting tools exist. These tools work by polling Continuous Integration servers for summary information and presenting it appropriately to users.
If a Continuous Integration server can offer a standard summary format, and a reporting tool can consume the same, then we get interoperability between reporting tools and CI Servers.
Over the years the CCTray format has become the de-facto standard for this purpose. Many CI servers implement their own, richer, APIs but also implement the CCTray feed to support various monitoring tools.
The current spec provides technical information about the CCTray format.
The servers page lists known servers and whether they support the CCTray format.
The clients page lists known clients that can read the CCTray format.
If you notice missing, inaccurate or out of date information, please submit a pull request on GitHub to get the information updated.