Regex Tester: Test & Debug Regular Expressions Online

What Are Regular Expressions?

Regular expressions (regex) are patterns used to match, search, and manipulate text. They're essential in programming for validation, parsing, and text processing.

Why Use a Regex Tester?

Writing regex without testing is like coding without running — you'll spend hours debugging. A regex tester gives you:

Instant visual feedback on matches

Highlighted matches in your test string

Match details including groups and positions

Flag toggles for global, case-insensitive, multiline

How to Use

Visit the [Regex Tester](/tools/regex-tester)

Enter your regex pattern

Set flags (g, i, m) as needed

Enter test text to match against

See highlighted matches and details in real time

Common Regex Patterns

Email Validation

`^[\w.-]+@[\w.-]+\.[a-zA-Z]{2,}$`

URL Matching

`https?:\/\/[^\s]+`

Phone Numbers

`$?\d{3}$?[-.\s]?\d{3}[-.\s]?\d{4}`

IP Address

`\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b`

Date (YYYY-MM-DD)

`\d{4}-\d{2}-\d{2}`

Regex Tips

Start simple and add complexity gradually

Use character classes `[a-z]` instead of listing characters

Test edge cases — empty strings, special characters, boundary cases

Add comments in your code to explain complex patterns

Frequently Asked Questions

Which regex flavor does this use?

JavaScript's built-in RegExp engine, which supports most common regex features.

Can I save my regex patterns?

Copy your pattern to save it. The tool processes everything in your browser session.

Does it support lookbehind?

Yes, modern JavaScript supports lookbehind assertions. ToolSphere uses your browser's regex engine.