Regex Tester

About Regex Tester

How to use Regex Tester

1. Enter a regex pattern in the 'Pattern' field. As you type, the 'Pattern Explanation' section automatically displays the meaning of each token, making complex patterns easy to understand.
2. Use the flag buttons (g, i, m, s, u) to customize the matching behavior. Select 'g' to find all matches globally, or 'i' to ignore case differences.
3. Paste your test text into the 'Test String' textarea. Matches, positions, values, and capture groups appear instantly in the 'Match Results' panel below.
4. Toggle 'Replace Mode' on, enter a replacement string, and see the substitution result in real time. Use backreferences like $1 or $2 to include capture groups in your replacement.
5. Click 'Common Patterns' to instantly insert popular regex patterns like emails, URLs, phone numbers, or dates, saving time and reducing errors.

Benefits of Regex Tester

• [Real-Time Verification] See match results update instantly as you type, speeding up your debugging workflow and reducing development time significantly.
• [Pattern Explanation] Every token in your regex is automatically explained, making complex patterns easy to understand. Learn syntax in real time while testing.
• [16 Built-In Patterns] Email, URL, phone number, date, hex color, UUID, password validation, and more — insert proven patterns with a single click instead of writing from scratch.
• [100% Client-Side] All processing happens in your browser with zero data transmission. Safely test text containing business data or personal information.
• [Preview Replacements] Test regex-based substitutions with full backreference support ($1, $2, etc.), making it perfect for real-world replacement tasks.