Regex tester online
Free online regex tester. Test regular expressions with match highlighting, capture groups and customizable flags in real time.
How it works
- 1
Write the regular expression
Enter the regex pattern in the dedicated field, using standard JavaScript syntax (e.g. \d+, [a-z], etc.).
- 2
Configure flags and paste text
Toggle the desired flags — g (global), i (case-insensitive), m (multiline), s (dotAll) — and paste the text to test the regex against.
- 3
Analyze the matches
The tool highlights all matches in green in real time and shows position, capture groups and total match count.
FAQ
What is a regular expression?
A regular expression (regex) is a search pattern used to find, validate or replace text. For example \d+ finds all numbers in a text.
What do the flags mean?
g = find all matches (not just the first), i = ignore case, m = ^ and $ work per line, s = dot . includes line breaks.
What are capture groups?
Parentheses () create capture groups that extract specific parts of the match. For example (\w+)@(\w+) captures user and domain separately from an email.
