Text-Tools

Regex Tester

Test and debug regular expressions with live matches.

100% Private - Your text never leaves your browser
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g = globali = insensitivem = multilines = dotall

About Regex Tester

Test regex patterns against sample text with real-time highlighting of matches, groups, and detailed match information. This free online tool processes your text instantly in your browser - no data is ever sent to any server, ensuring complete privacy.

How to Use Regex Tester

  1. Paste or type your text in the input field on the left
  2. The result appears automatically in the output field
  3. Adjust any options below the text fields if available
  4. Click "Copy Result" to copy the output to your clipboard
  5. Use "Download" to save the result as a text file

Features

  • ✓100% Free - No registration required
  • ✓Instant processing as you type
  • ✓Complete privacy - works offline
  • ✓No file size limits
  • ✓Works on all devices
  • ✓Download results as text file

Why Use Our Regex Tester?

Unlike other online tools that require uploads or send your data to servers, our regex tester runs entirely in your browser using JavaScript. This means your sensitive text never leaves your computer, making it perfect for processing confidential documents, personal information, or any text you want to keep private. The tool is also lightning-fast since there's no network latency involved.

When to Use This Tool

Email Validation

Test and refine regex patterns for validating email addresses in forms.

Data Extraction

Extract specific patterns like phone numbers, URLs, or dates from large text files.

Code Refactoring

Find and replace code patterns across multiple files using regex search.

Log File Parsing

Extract error messages, timestamps, or specific events from server logs.

Examples

Email Pattern

Pattern: [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}
Test: [email protected]
Match: [email protected]

💡 Validates standard email format

Extract Numbers

Pattern: \d+
Test: Order #12345 costs $99
Matches: 12345, 99

💡 \d+ matches one or more digits

URL Matching

Pattern: https?://[^\s]+
Test: Visit https://example.com now
Match: https://example.com

💡 Matches HTTP and HTTPS URLs

Common Mistakes to Avoid

⚠️

Greedy vs. lazy quantifiers

Solution: Use .*? (lazy) instead of .* (greedy) when you want the shortest match. Example: Extract text between tags.

⚠️

Forgetting to escape special characters

Solution: Characters like . + * ? [ ] { } ( ) | \ ^ $ need backslashes: \. to match a literal period.

⚠️

Not testing edge cases

Solution: Test with empty strings, very long strings, special characters, and Unicode. Regex that works in theory often fails in practice.

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