Test String

Substitution

The substitution result will appear here.

Match Results

No matches found.

Library

1. Input Your Pattern

Enter your regular expression pattern between the two forward slashes (/). Configure flags like **g (Global)** or **i (Case-insensitive)** next to the pattern input. Any syntax errors will be displayed in real-time.

2. Enter Your Test String

Paste or type the text you want to test in the large text area on the left. All matching parts of the text will be **highlighted instantly**, providing immediate visual feedback.

3. Check Results and Substitution

The right panel shows the total number of matches and detailed information for each match, including captured groups. Use the 'Substitution' section below the test string to preview how your regex and replacement pattern will modify the text.

Q. Is my data saved on your server?

A. **No.** This tester runs entirely using 100% local (client-side) JavaScript within your web browser. Neither your regex patterns nor your test strings are ever sent to a server, ensuring complete privacy and security.

Q. How does the Share link work?

A. The 'Share' button encodes your current regex, flags, and test string into the URL's Hash (#) segment. When shared, the recipient's browser loads the exact same state locally without relying on any server-side database.

Q. Which regex flavor is supported?

A. This tool uses the native JavaScript engine, meaning it primarily supports the **ECMAScript (JavaScript)** regular expression standard. However, the 'Code Generation' tab provides boilerplate code for Python, PHP, and Java as well.