Jenkins - Jenkins is an open-source continuous integration server with 300+ plugins to support all kinds of software development
CircleCI - CircleCI gives web developers powerful Continuous Integration and Deployment with easy setup and maintenance.
Semaphore - Semaphore is a fully managed, high performance testing and deployment solution for your company. A Continuous Integration tool.
Travis CI - Focus on writing code. Let Travis CI take care of running your tests and deploying your apps.
Heroku CI - Continuous Integration from Heroku
Codeship - Codeship is a fast and secure hosted Continuous Delivery platform that scales with your needs.