Browser-first · No sign-up
Regex Tester – Test Regular Expressions Online
Test regular expressions with flags and see matches instantly.
No uploads. Everything runs locally in your browser.
Regex tester
Test regular expressions with flags, see matches and positions instantly, and tweak patterns without sending data to a server.
Use examples to jump-start common patterns like emails, URLs, dates, and numbers.
Pattern
Flags
Text
Matches
- foo at index 0
- bar at index 8
What is this tool
This regex tester lets you try regular expressions with flags, preview matches and positions, and iterate quickly—all in your browser.
Use cases
- Validate form inputs like emails, URLs, and numbers.
- Debug search-and-replace patterns before using them in code.
- Test extraction rules for logs, CSVs, or text files.
- Prototype regex for scripts, API filters, or data pipelines.
Popular ways to use this tool
How to use
- Enter a regex pattern and optional flags (g, i, m, s, u, y).
- Paste sample text to test against the pattern.
- Review matches with their positions and tweak the regex as needed.
Features
- Client-side regex testing for privacy
- Supports standard flags (g, i, m, s, u, y)
- Shows matched text with positions
- Quickly switch patterns with examples
- Works on desktop and mobile browsers
FAQ
Is this regex tester free?
Yes. It runs in your browser at no cost.
Is my text sent to a server?
No. Matching happens locally in your browser.
Can I test with flags?
Yes. Use flags like g, i, m, s, u, y as needed.
Does it work on mobile?
Yes. You can test regex patterns on phones and tablets.
Can I see match positions?
Yes. Each match shows its index in the text.