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Regex Tester

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About Regex Tester

The Regex Tester lets you write, test, and debug regular expressions against live text with instant match highlighting. Matches are highlighted in real-time as you type. Captured groups are displayed clearly below the text.

One-click templates instantly load a ready-made pattern and sample text for common extraction tasks — emails, URLs, phone numbers, numbers, IP addresses, hashtags, mentions, dates, hex colors, and prices — so developers and marketers can pull structured data out of raw text without writing a pattern from scratch.

This tool supports full JavaScript (ECMAScript) regex syntax, including lookaheads, lookbehinds, named capture groups, character classes, quantifiers, anchors, and Unicode properties.

Regular expressions are a powerful tool for text processing, data validation, log parsing, search-and-replace, and text extraction. Testing them against real data before using them in your code prevents bugs and saves time.

Everything runs locally in your browser. Your data never leaves your device, and no account or sign-up is required.

Practical Uses for Regex Tester

  • Extract every email address from a block of pasted text
  • Pull all URLs out of a document or webpage source
  • Validate a phone number format before saving it to a database
  • Extract all hashtags from a batch of social media posts
  • Pull every price mentioned in a product description
  • Test a regex pattern before deploying it in production code

How to Use Regex Tester

  1. Click a template (Emails, URLs, Numbers, etc.) to instantly load a ready-made pattern and sample text — or write your own pattern in the Pattern field.

  2. Select flags: global (g), case-insensitive (i), multiline (m), dotall (s).

  3. Paste your own text in the input area to test it against the pattern.

  4. Matches are highlighted in real-time and captured groups are shown below.

Examples

Example — Match email addresses
Example — Match numbers
Input
Order 123 contains 4 items costing $56.78
Output
Matches: 123, 4, 56, 78
Example — Extract URLs
Input
Check out https://example.com and https://another-site.org for more info
Output
Matches: https://example.com, https://another-site.org
Example — Extract hashtags
Input
Loving this #newlaunch and #productivity boost!
Output
Matches: #newlaunch, #productivity
Example — Extract hex colors
Input
Brand colors: #FF5733 and #33FF57
Output
Matches: #FF5733, #33FF57
Example — Extract prices
Input
Prices range from $19.99 to $149.00
Output
Matches: $19.99, $149.00

Who Uses the Regex Tester Tool

  • Developers test and debug regex patterns against real sample data before deploying them in code.
  • Data analysts extract emails, phone numbers, or IDs from unstructured text exports.
  • Marketers pull hashtags, mentions, or URLs from social media exports for reporting.
  • QA engineers validate that input-format regex rules correctly match and reject sample data.
  • Content moderators extract flagged patterns like emails or phone numbers from user-submitted text.

Comparisons

Regex Tester vs Find & Replace

The Regex Tester is built for exploring and debugging a pattern — it highlights every match live, shows captured groups separately, and lets you try templates for common patterns like emails or URLs without changing your original text.

Find & Replace is built for applying a pattern to actually transform text — once you know your pattern works, use Find & Replace to run the substitution across your real data. A typical workflow is to perfect the pattern here first, then paste it into Find & Replace to do the actual replacement.

Frequently Asked Questions

What do the template buttons do?

Each template button (Emails, URLs, Phone Numbers, Numbers, IP Addresses, Hashtags, Mentions, Dates, Hex Colors, Prices) instantly fills in a tested regex pattern plus sample text, so you can see real extraction results immediately and adapt the pattern to your own data.

What regex syntax is supported?

Full JavaScript (ECMAScript) regex syntax including lookaheads (?=...), lookbehinds (?<=...), named groups (?<name>...), character classes, quantifiers, anchors (^ $), and Unicode.

How do I match a literal dot or parenthesis?

Escape special characters with a backslash: \. matches a literal dot, \( matches a literal opening parenthesis.

What does the global flag (g) do?

The global flag finds all matches in the text instead of stopping at the first match.

How do I match an email address?

A basic pattern: [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}

How do I match a URL?

A basic pattern: https?:\/\/[^\s/$.?#].[^\s]* — for production use consider a well-tested library.

Can I use named capture groups?

Yes — syntax: (?<groupName>pattern). The named groups are displayed in the capture group panel below the text.

Can I extract all the URLs from a block of text?

Yes — click the URLs template to load a ready-made pattern, then paste your text to see every URL extracted and listed as a match.

Can I validate a phone number format?

Yes — write or load a phone number pattern, then test various sample inputs to confirm your pattern correctly matches valid formats and rejects invalid ones.

Can I extract hashtags from social media posts?

Yes — click the Hashtags template, or write a pattern like #\w+ to match every hashtag in your pasted text.