RegExr
Tool for creating, testing, and learning about Regular Expressions
... in My Patterns. Explore results with the Tools. Replace & List output custom results. Details lists capture groups. Explain describes your expression in plain English. It provides full RegEx Reference with help & examples. Undo & Redo with ctrl-Z / Y in editors. Search for & rate Community Patterns. You can also group multiple tokens together and create a capture group for extracting a substring or using a backreference.