Free Regex Tester Online

Test and debug regular expressions instantly. Highlight matches, apply flags, and validate patterns with ease.

⚡ Instant Formatting 🔒 100% Secure 💻 Browser-Based

Use Tool Learn more

No sign-up, no tracking of your input, and nothing is stored on our servers.


// DevUtilityLab quick demo
const token = getJwt();
const payload = DevUtilityLab.jwt.decode(token);
if (payload.expired) {
  console.log("Token expired");
}

Regular expressions are a superpower, yet, as with any power, we require practice. Experimentation in a regex tester online with immediate feedback and your data not being shared is the quickest method of learning.

Regex Tester Tool

The regex tool of DevUtilityLab is all that, simple, fast, and safe. It works well regardless of whether you are a beginner who wants to understand the functionality of regex or a senior developer who wants to have a reliable tool for generating regex matches.

Regex Tester

Test regular expressions and highlight matches in real time.

Pattern

Flags g i m

Test String

Matches 0 matches

What is a Regular Expression (Regex)?

A regex (regular expression) is a pattern of characters expressing a search pattern. You can use it to search, substitute, or authenticate data.

Why DevUtilityLab is the Best Regex Tester Online?

🔍 Test Patterns Instantly

Check your regex patterns against real text in seconds.

⚡ Real-Time Feedback

See matches highlighted immediately as you test patterns.

🧠 Debug Faster

Understand complex regex expressions with visual results.

🔒 Client-Side Privacy

The regex patterns and text do not leave your browser. We do not keep your data on a server like other testers.

Example

Pattern

\b\d{3}-\d{3}-\d{4}\b

Match Result

123-456-7890

Key Features

Test regex patterns instantly
Supports multiple flags (g, i, m)
Real-time match highlighting
Fast and lightweight
Secure — no data stored

How to Test Regex Online Like a Pro

Ready to give it a try?It is a basic workflow to utilize our regex tester most:

Start with a small example. Pasting a large file is inappropriate; instead, paste a short string, which depicts your use case.
Use flags wisely. The g (global) flag includes all the matches; i is case-insensitive.
Check capture groups. In case your pattern has parentheses ( ), the table view will give you the precise data that each group has taken.
Iterate. Test the pattern, observe how matches vary, and perfect.

When you familiarize yourself with regex, you will use it as your text utility of choice. And when dealing with structured data, such as cleaning up a sloppy JSON file or rewriting SQL queries, our JSON Formatter or SQL Formatter can make the data clear to you, and then you apply your regular expression patterns.

How It Works

Type or paste your regular expression (e.g., \b\w+@\w+\.\w+\b for emails).
Paste the text you wish to search.
Instantly see matched strings highlighted. Filter search by changing the flags and patterns.

Frequently Asked Questions

What is a regex tester?

A regex tester is a program that lets you write and test regular expressions on a sample string. It displays matching graphically to allow you to debug your pattern logic.

How do I test a regex online?

Just enter your pattern in the Regex field, enter your text in the Test String field, and the matches will appear immediately.

Is this tool free to use?

Our regex tester is free, yes. The API also comes with a generous free plan for developers.

Can my information be secure in this tool?

Absolutely. We prioritize privacy. Our regex tester executes it all locally inside your browser using JavaScript. Your regex patterns and data are not sent to a server.