Travis CI - Focus on writing code. Let Travis CI take care of running your tests and deploying your apps.
CircleCI - CircleCI gives web developers powerful Continuous Integration and Deployment with easy setup and maintenance.
Sentry.io - From error tracking to performance monitoring, developers can see what actually matters, solve quicker, and learn continuously about their applications - from the frontend to the backend.
10words.io - Discover new apps and startups in 10 words or less
Buildbot - Python-based continuous integration testing framework
Heroku CI - Continuous Integration from Heroku