Microsoft added a very cool feature to VS-Online which called "Service Hooks".
The new feature (which will be added to the next version of TFS on premise) connect between your other
ALM/DevOps/etc. system to TFS.
Take a look at the list below for currently supported services:
In the list you may find a lot of useful services (Jenkins is also integrated...), I guess that one of the most popular hook will be the Web Hooks which provided event communication via HTTP, which is familiar to the TFS SOAP alerts. The Web Hooks give you the ability to choose what data to send (and not just the original template), also you may select the format of the message (text, HTML, Markdown, None etc.)
In order to config your own hooks you should:
1. Login to your Visual Studio On-Line
2. Select the project that you want to get hooked
3. go to "Service Hooks" Tab
*As for today its still in "Preview" mode