SQL Injection Cheat Sheet : Samples are provided to allow reader to get basic idea of a potential SQL Injection attack and almost every section includes a brief information about...
Pattern Tap : Organized Web Design Collection of User Interfaces for Inspiration and Ideas. The CSS Gallery Alternative
HTTP API design : This guide describes a set of HTTP+JSON API design practices, originally extracted from work on the Heroku Platform API.
regex101 : Free PCRE-based regular expression debugger with real time explanation, error detection and highlighting.
Mobile HTML5 compatibility : HTML5 compatibility on mobile and tablet browsers with testing on real devices
This is a collection of known design patterns and some sample code how to implement them in PHP. Every pattern has a small list of examples (most of them from Zend Framework, Symfony2 or Doctrine2 as I'm most familiar with this software).