Regex Form Validation Tester
Regular expressions for forms are famously tricky. Our tester helps you verify that your validation patterns catch invalid inputs while correctly allowing valid ones.
When to use this solution:
Use this during frontend or backend development to ensure your user registration and profile forms are robust.
Common Use Cases
1Step-by-Step Guide
Enter your pattern
Type your validation regex (e.g., ^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$) into the pattern field.
Add test cases
Paste a list of both valid and invalid examples into the test string area.
Check highlighting
Ensure that all valid examples are highlighted in yellow, and invalid ones are not.
Fix and retest
If a valid case isn't matching, adjust your pattern and watch the updates in real-time.
Ready to get started?
Use our free tool to solve this problem in seconds. No installation required.
Test Validation PatternsFrequently Asked Questions
Which flags should I use for validation?
Usually, you don't need 'g' for single-field validation, but 'm' might be useful if you're testing multi-line inputs.
Can I test complex password rules?
Yes, lookarounds and character classes are fully supported by our JavaScript regex engine.