Regex Tester
Test and debug regular expressions with real-time matching and capture groups
About the Regex Tester
Test regular expressions against sample text and see matches highlighted live. Regex is powerful but famously easy to get wrong — testing against real examples before deploying saves hours of debugging.
Regular expressions describe text patterns, and they appear everywhere in development: validating email addresses and phone numbers in forms, searching and replacing across a codebase, parsing log files, extracting data from text, URL routing rules, and input sanitisation. Nearly every language and editor supports them.
The building blocks are worth memorising: \d matches any digit, \w a word character, \s whitespace, . any character, * zero or more, + one or more, ? optional, ^ start of string, $ end. Two mistakes cause most pain: greedy matching, where .* grabs far more than intended (use .*? for lazy matching), and forgetting to escape special characters — a literal dot must be written \. or it matches everything.