Regex Tester

Test regular expressions with live highlighting. AI generates regex from plain English. Free, instant, 100% private.

/ /g

AI Regex Generator

Match Details

Regex Quick Reference

PatternMatches
\dAny digit [0-9]
\wWord character [a-zA-Z0-9_]
\sWhitespace
.Any character
* + ?0+, 1+, 0 or 1
{n,m}n to m times
^ $Start / end of line
\bWord boundary
[abc]Character class
(...)Capture group
(?:...)Non-capturing group

About Regex Tester

Test and debug regular expressions in real-time. JavaScript and PCRE flavors. See matches, groups, and match positions. Explain mode breaks down complex patterns. All in your browser.

Real-Time Matching

Type your regex and see matches instantly. All matches highlighted with color-coded capture groups.

Match Details

See full match, individual groups, start/end positions, and match count. Export results as JSON.

Flags Support

Toggle global (g), case-insensitive (i), multiline (m), dotAll (s), and unicode (u) flags.

Cheat Sheet

Built-in regex reference with common patterns, quantifiers, character classes, and anchors.

📋 Common Use Cases

Building Validation Patterns

Test and refine regex patterns for form validation — emails, phone numbers, postal codes — against multiple inputs to catch edge cases.

Debugging Complex Expressions

Step through layered regex patterns one capture group at a time to understand which part matches which portion of your text.

Extracting Data from Logs

Write regex to pull specific fields like IP addresses, timestamps, or error codes from structured or semi-structured log files.

Learning Regular Expressions

Experiment with regex syntax in a risk-free environment, seeing each metacharacter and quantifier's effect highlighted in real time.

🪜 How to Use This Tool

  1. Enter your regex pattern
    Type or paste a regular expression in the pattern input field without surrounding delimiters.
  2. Add test text
    Paste sample text into the test area to see which portions match your pattern with live highlighting.
  3. Toggle regex flags
    Enable flags like global (g), case-insensitive (i), multiline (m), or dotall (s) and watch matches update instantly.
  4. Review capture groups
    Inspect extracted capture group values in a separate panel to verify your groupings produce the expected sub-matches.

📚 Related Guides

Frequently Asked Questions

Are these dev tools free?▼
Yes. All dev tools are completely free. No signup, no account.
Is my data sent to a server?▼
No. Base64 encoding, URL encoding, JWT decoding, hash generation, and regex testing all happen in your browser. Your tokens and secrets stay on your device.
Can I decode JWTs safely?▼
Yes. JWT decoding happens entirely in your browser. The token never leaves your device. Only the header and payload are decoded — signatures are not verified server-side.

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