Regex Tester

Validate your regular expressions with real-time matching, detailed group analysis, and syntax highlighting.

info

Enter both pattern and test text to start matching.

//
g

Flags

Global (g)

Don't return after first match

Multiline (m)

^ and $ match strat/end of line

Case Insensitive (i)

Case-insensitive matching

Match Information

0

Matches

0

Groups

No results found.

helpQuick Reference

  • .Any Character
  • \wWord Character
  • \dAny Digit
  • \sWhitespace
  • [abc]Character Class
  • (...)Capture Group
  • ^ / $Start / End
  • * / +Zero+ / One+

starMost Popular Regexes

Email Address

Matches standard email addresses.

/^[\w.-]+@([\w-]+\.)+[\w-]{2,4}$/g

URL / Website

Matches HTTP and HTTPS URLs.

/^https?:\/\/(?:www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b(?:[-a-zA-Z0-9()@:%_\+.~#?&\/=]*)$/g

IPv4 Address

Validates an IPv4 address.

/^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/g

Phone Number (US)

Matches US phone numbers, including extensions.

/^(?:(?:\+?1\s*(?:[.-]\s*)?)?(?:\(\s*([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9])\s*\)|([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9]))\s*(?:[.-]\s*)?)?([2-9]1[02-9]|[2-9][02-9]1|[2-9][02-9]{2})\s*(?:[.-]\s*)?([0-9]{4})(?:\s*(?:#|x\.?|ext\.?|extension)\s*(\d+))?$/g

Strong Password

1 uppercase, 1 lowercase, 1 number, 1 special char, 8+ length.

/^(?=.*?[A-Z])(?=.*?[a-z])(?=.*?[0-9])(?=.*?[#?!@$%^&*-]).{8,}$/g

Hex Color

Matches 3 or 6 digit hex color codes.

/^#?([a-fA-F0-9]{6}|[a-fA-F0-9]{3})$/g

rulePattern Debugger

Regex Tester Online (Regex Match and Pattern Debug Tool)

Use this Regex Tester Online to test regular expressions instantly, debug edge cases, and validate matching logic before deploying code. It is designed for fast pattern checks with real-time feedback, making regex work easier for developers and analysts.

Build better validators, parsers, and extractors with a free regex tool that runs directly in your browser.

How to Use the Regex Tester

Follow these quick steps to test a regular expression:

  1. 1Enter your regex pattern in the pattern input field.
  2. 2Enable flags like g, i, or m based on your matching behavior.
  3. 3Paste sample text or logs in the test string area.
  4. 4Review highlighted matches, indexes, and capture groups instantly.

This workflow helps you verify expected behavior and catch matching errors early.

Why Use an Online Regex Tester?

Regex is powerful but easy to get wrong. A tester helps you:

  • task_altDebug pattern behavior before using regex in production code.
  • task_altValidate capture groups for parsing and extraction workflows.
  • task_altTest multiline and case-insensitive behavior in one place.
  • task_altReduce false matches that can cause data or validation issues.

Testing patterns before release reduces bugs in parsing, search, and validation flows.

Features of This Regex Pattern Tester

  • check_circleReal-time regex matching as you type.
  • check_circleSupport for global, multiline, and case-insensitive flags.
  • check_circleCapture group visibility for each match.
  • check_circleInline match highlighting over test input.
  • check_circleClient-side processing for privacy and speed.
  • check_circleWorks across desktop and mobile browsers.

Common Regex Testing Use Cases

Teams use regex test tools in many day-to-day workflows:

  • task_altValidating emails, URLs, phone numbers, and identifiers.
  • task_altBuilding log filters and extraction rules.
  • task_altTesting search-and-replace expressions safely.
  • task_altCreating form validation patterns for web apps.
  • task_altVerifying patterns before shipping backend parsers.

A tested pattern is more reliable than one copied without validation.

Regex Pattern Debug Tips

Keep these best practices in mind when refining your expressions:

Use non-greedy quantifiers like *? when needed.Escape special characters such as . + ? ( ) [ ] { }.Turn on m when using ^ and $ with multi-line text.Avoid over-broad wildcards to reduce false positives.

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Frequently Asked Questions (FAQ)

What is a regex tester?

A regex tester online lets you test regex patterns against sample text and instantly review matches, positions, and groups before shipping validators or parsers.

What is a Regular Expression (Regex)?

A regular expression (regex) is a pattern language used to search, validate, and extract text such as emails, IDs, dates, and log fragments.

What are capture groups?

Capture groups are parts of a pattern wrapped in parentheses. They isolate submatches so you can extract values, reuse them in replacements, or analyze parsed segments.

What do the regex flags mean?

Flags change matching mode: g finds every match, i ignores letter case, and m makes ^ and $ apply per line in multiline text.

Is this regex tester safe?

Yes. This regex pattern tester runs entirely in your browser, so your regex and sample text stay local and are not uploaded.

Can I test regex for JavaScript patterns here?

Yes. It follows JavaScript RegExp behavior, so it is suitable for front-end form validation, Node.js parsing, and JS regex debugging.