Regex Tester & Explainer
Write and debug your regular expressions with ease. Get real-time highlighting and a breakdown of your pattern's structure to understand exactly what matches and why.
Test String
Pattern Explainer
Match Groups
No matches to show.
Regex Quick Reference
Character Classes
.- Any character except newline\d- Any digit (0-9)\w- Any word character (a-z, A-Z, 0-9, _)\s- Any whitespace (space, tab, etc.)[abc]- Any character in the set
Quantifiers
*- 0 or more+- 1 or more?- 0 or 1{n}- Exactly n times{n,}- n or more times
Anchors & Groups
^- Start of string/line$- End of string/line(abc)- Capture group(?:abc)- Non-capturing group\b- Word boundary
Regex Tester & Explainer FAQs
What is a Regular Expression (Regex)?
A Regular Expression is a sequence of characters that forms a search pattern. It's used for string matching and manipulation, allowing you to search, validate, or replace text based on complex criteria.
How do I use this Regex Tester?
Enter your regex pattern in the top input box (without the leading and trailing slashes). Select any flags you need (like global or case-insensitive) and then provide a test string in the main area. Matches will be highlighted automatically.
What do the regex flags do?
Flags change how the regex engine behaves. 'g' (Global) finds all matches instead of just the first one. 'i' (Ignore Case) makes the match case-insensitive. 'm' (Multiline) treats the start and end anchors (^ and $) as working on each line, not just the whole string.
Does this tool support all regex features?
This tool uses the standard JavaScript RegExp engine, which supports features like lookaheads, lookbehinds (in modern browsers), named capture groups, and Unicode properties.