Regex Tester — Live Match Highlighting

Test regular expressions with instant highlighting, flag toggles, and a detailed match list.

Regular Expression

//gi

Test String

Matches 11

Hello World! The quick brown fox jumps over the lazy dog.

Match Details

1Hello@0

2World@6

3The@13

4quick@17

5brown@23

6fox@29

7jumps@33

8over@39

9the@44

10lazy@48

11dog@53

How to Use the Regex Tester

1
Enter your regex pattern
Type your regular expression in the pattern field. The / delimiters are shown for clarity but should not be included in your input.
2
Toggle flags
Enable g (global), i (case insensitive), m (multiline), or s (dotall) flags using the flag buttons.
3
Type your test string
Enter or paste the text you want to test against in the Test String area.
4
See live highlights
All matches are highlighted in amber in the preview area as you type.
5
Review match details
The match list shows each match, its position index, and a copy button for individual matches.

Your Privacy Is Guaranteed

Unlike most online tools, Toolivon processes everything directly in your browser using the Web APIs built into Chrome, Firefox, Safari, and Edge.

✓Your files are never uploaded to any server
✓Nothing is stored after you close the tab
✓No account or email is required
✓Works offline once the page is loaded
✓GDPR-friendly by design — no data leaves your device

Learn how it works →

Your data never leave your device

All processing runs directly in your browser using built-in Web APIs — the Canvas API, Web Audio API, and WebAssembly. Nothing is uploaded to any server. There is no account, no email, and no data retention. You can verify this yourself: open your browser's DevTools Network tab and watch zero outbound file requests while the tool processes your data.

GDPR-friendly · Works offline after page load · No file size limits beyond your device memory

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How to Use the Regex Tester

Enter your regex pattern

Type your regular expression in the pattern field. The / delimiters are shown for clarity but should not be included in your input.

Toggle flags

Enable g (global), i (case insensitive), m (multiline), or s (dotall) flags using the flag buttons.

Type your test string

Enter or paste the text you want to test against in the Test String area.

See live highlights

All matches are highlighted in amber in the preview area as you type.

Review match details

The match list shows each match, its position index, and a copy button for individual matches.

Your Privacy Is Guaranteed

Unlike most online tools, Toolivon processes everything directly in your browser using the Web APIs built into Chrome, Firefox, Safari, and Edge.

✓Your files are never uploaded to any server

✓Nothing is stored after you close the tab

✓No account or email is required

✓Works offline once the page is loaded

✓GDPR-friendly by design — no data leaves your device