Currently, Codenvy provides runtime environment for Java (WAR only!), Python, PHP, Node.js and HTML/JS applications. To run your application go to Run > Run Application menu. Building a project (for Java) and starting an application may take a while, depending on the application complexity.
You will see a temporary application URL in the Output tab:
[INFO] Starting project pyhton2... [INFO] Application app-r9foewn3nboypwt3 started on http://app-r9foewn3nboypwt3.apprun3.codenvycorp.com
You can stop the application at Run > Stop application. After 10 minutes the app will stop automatically, so if you need more time to interact with your application, you will have to re-run it.