Tag magento codesniffer
Available Magento Code Sniffer rulesets
Basically I recommend following the PSR-2 standardfor Coding Style Guidelines in Magento projects. Verifying your coding styles makes sense in any case – whether you are working in a large team of developers or as a freelancer for several clients. Agreeing to one common coding standard and following the rules improves readability and comparability. But as we all know Magento has some quirks that do not fit very well this standard (like underscore class names, underscore prefixed variables, etc.