Regex Tester Tool | Test & Debug Regular Expressions Online

Regex Tester Tool

Free online tool to test, debug, and validate regular expressions. Experiment with regex patterns in real-time with detailed matching results.

Regular Expression Pattern

i (case insensitive) g (global match) m (multiline) s (dotall) u (unicode)

Test Text

Results will appear here. Enter a regex pattern and test text, then click "Test".

Matches found: 0

Test your regular expressions against sample text with immediate feedback and highlighting of matches.

Identify issues in your patterns with detailed error messages and match information.

Toggle between different regex flags (like global, case-insensitive) to see how they affect matching.

Regex Cheatsheet

Pattern	Description	Example
`.`	Any character except newline	`a.c` matches "abc", "a2c", etc.
`\w`	Word character (a-z, A-Z, 0-9, _)	`\w+` matches words
`\d`	Digit (0-9)	`\d{3}` matches 3 digits
`^`	Start of string (or line with m flag)	`^Hello` matches "Hello" at start
`$`	End of string (or line with m flag)	`end$` matches "end" at end
`*`	0 or more of preceding element	`a*b` matches "b", "ab", "aab", etc.
`+`	1 or more of preceding element	`a+b` matches "ab", "aab", etc.
`?`	0 or 1 of preceding element	`a?b` matches "b" or "ab"
`{n}`	Exactly n occurrences	`a{3}` matches "aaa"
`[abc]`	Any of a, b, or c	`[aeiou]` matches vowels
`(...)`	Capturing group	`(abc)+` matches "abc", "abcabc", etc.
`\s`	Whitespace character	`\s+` matches spaces/tabs
`\b`	Word boundary	`\bword\b` matches whole word

Type your regular expression in the pattern field. Use the checkboxes to toggle regex flags that affect matching behavior.

Enter or paste the text you want to test your regular expression against in the test text area.

Click "Test" to see matches highlighted in the text and get information about the number of matches found.