Regex Tool: Pattern Editor Help & FAQ

How to test a regex pattern on iPhone

Build and verify a pattern in seconds with live highlighting.

1. Open Regex Tool and tap the New Pattern button.
2. Type your pattern in the top field (for example, \b\w+@\w+\.\w+\b).
3. Paste sample text into the test area below.
4. Watch each match highlight as you type. Capture groups are listed under the match.
5. Toggle the i, m, or s flags from the toolbar if you need different matching behavior.

How to extract all email addresses from a block of text

A common real-world task that takes one pattern and one tap.

1. Paste the block of text into the test area.
2. Use the pattern: [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}
3. Make sure the global flag is on so all matches are listed (this is the default).
4. Open the Matches panel and tap Copy All to put every match on the clipboard, one per line.
5. Paste into Notes, Mail, or any other app.

For very strict email validation use a fuller pattern, but the one above catches almost everything you encounter in the wild.