The leading open source automation server, Jenkins provides hundreds of plugins to support building, deploying and automating any project. As an extensible automation server, Jenkins can be used as a simple CI server or turned into the continuous delivery hub for any project. Jenkins is a self-contained Java-based program, ready to run out-of-the-box, with packages for Windows, Mac OS X and other Unix-like operating systems. Jenkins can be easily set up and configured via its web interface, which includes on-the-fly error checks and built-in help. With hundreds of plugins in the Update Center, Jenkins integrates with practically every tool in the continuous integration and continuous delivery toolchain. Jenkins can be extended via its plugin architecture, providing nearly infinite possibilities for what Jenkins can do. Jenkins can easily distribute work across multiple machines, helping drive builds, tests and deployments across multiple platforms faster.
Currently CircleCI only provides early, limited access for iOS builds on CircleCI Enterprise that run on their own cloud of macOS machines.Continuous Integration Tools CircleCI (Linux)