Travis CI is a hosted continuous integration service used to build and test software projects hosted on GitHub, Bitbucket, GitLab, Perforce, Apache Subversion and Assembla.
Travis CI was the first CI service that provided services to open-source projects for free but as December 2020 no longer does so. TravisPro provides custom deployments of a proprietary version on the customer's own hardware.
The main software is proprietary. Some adjacent tools like API clients are open-source.