Text Counter
Count characters, lines, words, and bytes in real time.
Regex Tester
Test regular expressions and highlight matches in real time.
Input data is processed in your browser
Data is never sent to a server
Tool
What is a Regular Expression?
A regular expression (regex) is a notation for describing a set of strings using a single pattern. It enables concise expression of complex string searching, replacing, and validation operations.
How to Use
- Enter a regex pattern in the pattern field.
- Enter test text in the text area.
- Matches are highlighted in real time.
- Adjust flags (g, i, m) as needed.
FAQ
Which regex engine is used?
JavaScript's built-in regular expression engine.
Can capture groups be inspected?
Yes. Each matched group's content and index position are displayed.
More Tools in This Category
- Regex Replace TesterTest regex search and replace in real time with match highlights and capture group details.
- Regex ExplainBreak down a regex pattern into color-coded tokens with plain-language explanations for each part.
- Regex EscapeAutomatically escape regex metacharacters in a string for safe use in patterns.
- Regex Cheat SheetA searchable quick reference for regex syntax — click any card to copy.