The SaaS CTO Security Checklist - The security checklist all CTOs should follow
rubular - A ruby based regular expression editor
The Security Checklist - The Practical Security Checklist for Web Developers
RegExr - RegExr.com is an online tool to learn, build, and test Regular Expressions.
Google Capture the Flag 2017 - Google's 2nd annual worldwide security competition
RegEx Generator - RegEx Generator is a simple-to-use application that comes with the brilliance of intuitive regex and is also helping you out to test the regex.