Free · Browser-Based · Flags · Replace Preview

Regex Tester

Test regular expressions with flags, inspect match positions, review captured groups, and preview replacements before using the pattern in code.

Pattern

Flags

Ignore case (i) Multiline (m) Dotall (s) Unicode (u)

Test Text

Replace With

Output

🎯 Common Use Cases

Debug patterns before putting them in code

Inspect exact match positions and capture groups

Try replacement strings safely

Toggle flags without retyping the regex

What makes this stronger than a basic regex box?

It supports quick flag toggles, match positions, capture groups, and replacement preview in one workflow.

What regex engine does it use?

It uses the browser's JavaScript RegExp engine, which matches common frontend and Node.js behavior closely.

Can I inspect groups?

Yes. Each match prints its capture groups, which helps when debugging replacements and nested patterns.