Test regular expressions online. The expression is evaluated as you type. Captures are displayed in a table and matching parts in your test text are marked with unique colors.
Use case-insensitive matching.
Use multiline mode, where ^ and $ match the beginning and end of each line (instead of the beginning and end of the input string).
Use single-line mode, where the period (.) matches every character (instead of every character except \n).
Do not capture unnamed groups. The only valid captures are explicitly named or numbered groups of the form (?<name> subexpression).
Exclude unescaped white space from the pattern, and enable comments after a number sign (#).
Change the search direction. Search moves from right to left instead of from left to right.
Enable ECMAScript-compliant behavior for the expression.
Ignore cultural differences in language.