JavaScript Regex Tester

Test a regex with this browser's JavaScript RegExp, flags and capture positions included.

This browser's JavaScript RegExp

Checking engine…

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Workspace actions
Regular expression
Reference

Regex quick reference

^ · $
Start/end; m = lines.
[abc] · \d
Listed character / digit.
* · + · ?
Zero or more, one or more, optional.
(...)
Capture a numbered group.
(?<name>...)
Named capture.
(?=...)
Ahead; lookbehind varies.
i · m · s
Ignore case / line anchors / dot-newline.
Browse the full reference

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the RegExp of this browser (version not pinned)

Not available in JavaScript · This browser: x · ignore pattern whitespace; a · ASCII-only classes; U · lazy by default; J · duplicate names. u and v cannot be combined.

To run: enter a regex; enter a test text.

Test text

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Verified Fixture FX-S05

What it does

Test a regex with the JavaScript RegExp of this browser, with capture positions and named groups.

How to use it

  1. Type or paste the regex.
  2. Paste the text to test; add more texts with Add text.
  3. Results appear as you type; press Ctrl/Cmd+Enter to run with the longer deadline.

Verified example

Example

Text "TX-00057"

JavaScript · This browser
(?<id>TX-\d{5})

Result: "TX-00057"; groups "TX-00057"

Python re · Local WASM
(?P<id>TX-\d{5})

Result: "TX-00057"; groups "TX-00057"

PCRE2-8 · Local WASM
(?<id>TX-\d{5})

Result: "TX-00057"; groups "TX-00057"

Go regexp · Local WASM
(?P<id>TX-\d{5})

Result: "TX-00057"; groups "TX-00057"

Counterexample

Text "TX-7"

JavaScript · This browser
(?<id>TX-\d{5})

Result: no match

Python re · Local WASM
(?P<id>TX-\d{5})

Result: no match

PCRE2-8 · Local WASM
(?<id>TX-\d{5})

Result: no match

Go regexp · Local WASM
(?P<id>TX-\d{5})

Result: no match

Recorded by running fixture FX-S05 on : rp.js@1 on Node v24.21.0 (V8), v24.21.0, CPython 3.14.2 (Pyodide 314.0.7), PCRE2 10.48, go1.27.1. JavaScript results come from the rp.js@1 core on Node’s V8; your browser runs the same core.

Engines

Limits