Regex Tester
Pattern
/
/
g
Regular expressions (regex) are a pattern language for matching and extracting text. They are supported in virtually every programming language and are essential for tasks like input validation, search-and-replace, and parsing structured data from logs or documents.
1.
Enter your regular expression in the pattern field
2.
Paste test text below - all matches are highlighted in real time
3.
Use the flags (g, i, m, s, u, y) to adjust matching behaviour
▸
Testing regex patterns for form validation (email, phone, postal code)
▸
Extracting structured data from log files or raw text
▸
Building search-and-replace patterns for scripts or editors
Which regex flavor does this use?
This tool uses JavaScript's built-in RegExp engine, which follows the ECMAScript regex specification. Patterns work the same as in Node.js and browser JavaScript.
How do I enable case-insensitive matching?
Click the i flag chip below the pattern field to toggle it on. All six flags (g, i, m, s, u, y) can be toggled independently.
What does the g flag do?
The global flag (g) finds all matches in the text instead of stopping after the first one. Match count and highlights update accordingly.
Is my text sent to a server?
All matching runs locally in your browser. No text or patterns are transmitted anywhere.
Why does my pattern match unexpectedly?
Special characters like . * + ? ( ) [ ] { } | ^ $ have meaning in regex. Escape them with a backslash if you want to match them literally (e.g., \. to match a period).