Regex Tester – Test Regular Expressions Online
Enter a regular expression pattern and a test string to see matches highlighted instantly. Supports global, case-insensitive, and multiline flags.
How to Use
- 1
Enter a regular expression pattern in the pattern field
- 2
Type or paste your test string in the text area
- 3
Matches are highlighted in real time — adjust your pattern as needed
Frequently Asked Questions
What is a regular expression?
A regular expression (regex) is a sequence of characters that defines a search pattern. It is used to find, match, and manipulate text based on rules like character classes, quantifiers, and anchors.
What does the global flag do?
The global flag (g) finds all matches in the string instead of stopping after the first one. Without it, the regex engine returns only the first match.
How do I match a literal dot or bracket?
Escape special characters with a backslash. For example, \. matches a literal dot, and \[ matches a literal opening bracket. Without escaping, . matches any character.
What does the multiline flag do?
The multiline flag (m) changes how ^ and $ behave. With multiline on, ^ matches the start of each line and $ matches the end of each line, not just the start and end of the whole string.
Test regular expressions live
A regex tester lets you write a regular expression and see in real time what it matches in your sample text. Matches are highlighted as you type, so you can refine the pattern without running code.
It turns the trial and error of regex into immediate, visible feedback.
What patterns get built for
- Building and debugging patterns for search, validation or scraping.
- Learning regex syntax by experimenting safely.
- Checking a pattern before dropping it into your code.
- Comparing two texts instead? Use the text diff. Counting words? The word frequency counter.
Your pattern and test text stay local
Your pattern and text are processed in your browser, so nothing is uploaded.