Free browser tool

Regex Tester

Test JavaScript regular expressions with presets, validation, match summaries, warnings, copyable output, and reset controls.

Updated 2026-05-15

Pattern Flags JavaScript flags. Global is added automatically.

Test text

How to use this tool

Paste or type your input into the tool.
Choose the action or option that matches your task.
Review the output before copying it into another app.

Notes

Run JavaScript regular expressions in the browser, try email or URL presets, review match counts and indexes, catch invalid patterns, and copy the match list.

Inputs are processed in the browser for this static MVP. Avoid pasting secrets into any online tool unless you understand the environment.

FAQ

Which regex syntax does this use?

It uses JavaScript regular expression syntax because the test runs in the browser. Flags such as i, m, s, u, and y follow browser support, and the global flag is added so all matches can be listed.

Why are only some matches displayed?

The tool shows and copies the first 50 matches to keep long inputs responsive. The summary still reports the total number of matches found.

Why did I get an empty-match warning?

Patterns such as .*? can match zero characters. That is sometimes intentional, but it often means the pattern is too broad for a practical search.

Can I paste private logs here?

The tool is designed for browser-side testing, but you should still avoid pasting secrets, tokens, private customer data, or production logs into any web page unless your rules allow it.

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