What is a regex tester?
A regex tester is a place to write a pattern, point it at some text, and instantly see every match. Instead of guessing, you watch the tool highlight exactly what your expression finds.
This tester shows each match with its position, flags all the common options, and keeps a quick reference of the patterns you will use most.
How to use this tool
- Type your pattern, like d+ for numbers.
- Paste or type the text to search.
- Watch the matches appear instantly as you type.
- Toggle flags to change how the pattern behaves.
A quick reference
- d matches any digit, w any word character.
- + means one or more, * means zero or more.
- ^ and $ anchor to the start and end.
- [abc] matches any one of the listed characters.
Why test before you ship
Regex looks simple and fails subtly. A missing escape or a too-greedy quantifier can silently break validation. Testing against real text first saves you from debugging later.
Frequently Asked Questions
A regular expression, or regex, is a pattern that searches text for matching pieces. Instead of searching for one exact word, you describe the shape of what you want to find.
Every match appears as a card showing its position in the text and the exact text that matched. The status line tells you how many matches were found.
g finds every match instead of stopping at the first, i ignores case, m makes ^ and $ work line by line, and s lets the dot match across newlines.
Regex is literal about spaces and case. Check for extra spaces, wrong case, or a missing escape. The error message usually points to the exact problem in the pattern.
Yes. The pattern and flags are standard JavaScript regex, so they work in any modern language or tool with minor differences in syntax.
No. Testing runs entirely in your browser. Your text and pattern never leave your device.