Test and debug regular expressions in real-time. See matches highlighted, capture groups extracted, and get explanations for your regex patterns.
Regular expressions (regex) are patterns used to match character combinations in strings. They are one of the most powerful and most feared tools in a programmer's arsenal. Nearly every programming language supports regex, and mastering them can turn hours of string manipulation into a single line of code.
ed in 1968 which gave us the grepcommand (Global Regular Expression Print). The famous programming joke "now you have two problems" comes from Jamie Zawinski's 1997 quip about regex overuse.Character classes ([a-z], \d, \w) match specific types of characters. Quantifiers (*, +, ?, {n}) control repetition. Anchors (^, $) match positions. Groups (()) capture subpatterns. Lookahead/lookbehind match without consuming characters. Start simple, test incrementally.
Write your pattern
Enter a regex pattern in the pattern field. Add flags like g (global) or i (case-insensitive).
Add test strings
Paste or type the text you want to test against. Matches highlight in real time.
Debug & refine
See captured groups, match indices, and step-by-step explanations to perfect your regex.
Backend developers
Validate emails, URLs, phone numbers, and other structured input formats.
Data engineers
Extract patterns from logs, CSVs, and unstructured text datasets.
DevOps engineers
Write log-parsing rules for monitoring tools like Datadog or Splunk.
Students
Learn regex interactively with real-time visual feedback on matches.
A regular expression (regex) is a pattern used to match character combinations in strings. They are used for searching, validating, and manipulating text in virtually all programming languages.
Common flags include: g (global - find all matches), i (case-insensitive), m (multiline), s (dotAll - dot matches newlines), u (unicode), and y (sticky).
Yes! All regex processing happens directly in your browser. No data is sent to any server.