What if my pattern is invalid?

Invalid syntax shows a clear error message without breaking the page. Fix the pattern and testing resumes automatically.

How are global (g) matches handled?

With the g flag, all non-overlapping matches are found. Empty matches advance the search index to avoid infinite loops.

Yes. Use the example buttons for email, phone, and URL patterns to fill the pattern and test text instantly.

Test and debug regular expressions with live highlighting. See matches and groups as you type. Runs entirely in your browser.

Runs locally — nothing is uploaded

1
Enter a pattern
Type a regular expression in the pattern field and select flags (g, i, m, s, u, y) as needed.
2
Add test text
Paste or type sample text. Matches are highlighted live as you edit the pattern or text.
3
Inspect matches
Review the match count, each match index, capture groups, and named groups in the results list.

g, i, m, s, u, and y — toggle them below the pattern field to change matching behavior.

Create styled QR codes for links, Wi‑Fi, contacts, and more. Logo and colors stay in your browser.

Developer Tools

Generate CODE128, EAN13, UPC, and CODE39 barcodes from text. Download as PNG.

Developer Tools

Format, validate, and minify JSON with clear error messages.

Developer Tools

Encode and decode text or images to Base64. Works entirely offline.

Developer Tools