Jenkins – 4 Months and Going Strong

The Jenkins/Hudson vote happened a bit over four months ago, on Jan 29th; a good time to check on the health of the Jenkins community.

Below are adoption indicators based on activity on Mailing Lists, Twitter, GitHub, and Web sites.  All these indicator are consistent with those published by Kohsuke a couple of weeks ago (post, slides) and show a very healthy project backed by a wide community.

Mailing Lists

The USER and DEV mailing lists are hosted through Google Groups but can also be accessed through portals like Nabble, and MarkMail.   MarkMail can also be used easily for historical analysis because the mailing groups moved to Google before the split and the Hudson mailing list has been archived there for years.

Below is the traffic on USER, which has remained consistently high, around 800 messages per month, over the last 5 months:

Traffic on Jenkins USER

The volume of traffic on DEV depends on what new development efforts are occurring.  Peak traffic was over 900 messages, in February.  The use of GitHub has modified some of the exchanges between developers, and “pull requests” are possibly also affecting the volume.

Traffic on Jenkins DEV

Combined, the monthly traffic is around 1,2K per month, with a peak of 1800 in February.

Traffic on Jenkins USER & DEV

Jenkins’s mail traffic is comparable to that of the old Hudson’s ML (USERs, DEV and Combined) and is only lower to the all-high records in mid-2009.

Another useful Mailing List metric is the number of subscribers, which have been growing steadily, even despite the growth in other communication mechanisms like twitter and despite the mail volume.  As of this writing, USER has over 1650 subscribers while DEV has over 950:

Subscriptions to Jenkins USER
Subscriptions to Jenkins DEV

Hudson charts can be used as reference and are available here and here.


Twitter has become a very convenient way to keep with the activity of a project, so the number of followers is a good adoption metric, and @jenkinsci shows very good growth:

Subscribers to @JenkinsCI

Subscriber trends for @hudsonci and @jenkins_release can be seen here, as reference points.


Jenkins’s move to Git and GitHub has been extremely successful, simplifying the release and contribution flows and facilitating community development like the Hackatons.  The move started before the Hudson/Jenkins split and has continued to gain momentum since then.  Additionally, many (most?) of the plugins for Hudson and Jenkins have moved to GitHub.

The core of GitHub are the repositories, which, in Jenkins case, are organized under the JenkinsCI organization, which has over 105 members and over 510 repositories.  The main repository (JenkinsCI/Jenkins) has over 200 forks.

The growth has been steady, below are the charts for members, forks, and repositories.  As reference, the corresponding charts for Hudson are here, here and here.

GitHub Members in JenkinsCI Organization
GitHub Repositories in JenkinsCI Organization
GitHub Forks of JenkinsCI/Jenkins Repository

GitHub also provides a very entertaining and pretty “Impact” graph showing how the different forks and contributions of a repository interact.  Here is the one for JenkinsCI/Jenkins (and that for Hudson is here):

GitHub Impact Graph for JenkinsCI/Jenkins

Finally, for entertainment value, the “GitHub Game” for Jenkins is here (and that for Hudson is here).


At this point I’d normally point to Google Trends on term searches, but, like with Hudson, Jenkins is too popular a name for term searches and the web site is not popular enough for website trends.  The best I can provide is use Alexa ranking.

I am not a fan of Alexa because the data is based only on users of the Alexa toolbar, because the data is all about relative rankings (and thus influenced by news events), because its statistical data is only available in some combinations (groupings/time), and because I find their rankings very unstable, but, for what is worth, below are two ranking (smaller is better) graphs; the first one is World rankings, the second is US rankings.  Corresponding graphs for Hudson are here and here.

Alexa World Ranking for Jenkins
Alexa US Ranking for JenkinsCI

Other indicators

Tyler’s post on The State of Jenkins and Kohsuke’s Slides have many other good indicators, including JIRA tickets, GitHub pull requests, Download numbers, and percentages of people choosing Jenkins in upgrades from pre-split releases.

In addition, here are some other indicators

Future: The Foundation Decision

The next key decision is which Umbrella Foundation will host Jenkins moving forward.  This was already discussed in the first Jenkins community meeting (Feb 4th) and was visited again in its last meeting (May 24th).  Pretty much all the information needed to make a decision has been collected – I think the only pending one was whether Apache governance was compatible with using GitHub.

In Closing… Go Jenkins!

All indicators have limitations, but if they all are pointing the same way, that is the way how the adoption is going… and that is the case here… Jenkins is extremely active, and I’m looking forward to its continued growth for years to come.


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