How Continuous Integration Service Basically some kind of task runner You push your code Your Git server triggers the CI service or server Your CI service or server builds and tests your code
Showcase Travis CI https://travis-ci.org Run PHP linter for multiple versions Extend the setup executing unit and functional tests Release new versions automatically to TER
How Software or service analyzing your PHP code Define your code styles Run the tool or trigger the service Possible triggers Own task in your CI build/test Service triggered by a Git push
How Software analyzing your PHP code Own metrics to parse code and find problems Your code is not executed Gets split in an abstract tree of PHP Parser Statements Different defined checks are executed