PCRE2 Regex Tester

Test a regex with PCRE2 10.48 compiled to WebAssembly (UTF mode, no JIT), loaded on request.

PCRE2 as WebAssembly, in this browser

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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.
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PCRE2 10.48, UTF, no JIT

Not available in PCRE2-8 · Local WASM: a · ASCII-only classes; u · Unicode; v · Unicode sets; y · sticky.

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

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Verified Fixture FX-S06

What it does

Test a regex with PCRE2 10.48 compiled to WebAssembly, in UTF mode without JIT.

How to use it

  1. Load the PCRE2 engine (its size is shown before the download).
  2. Type or paste the regex.
  3. Paste the text to test; add more texts with Add text.
  4. Results appear as you type; press Ctrl/Cmd+Enter to run with the longer deadline.

Verified example

Example

Text "ID=42 code=9"

JavaScript · This browser
(?<=ID=)\d+

Result: "42"

Python re · Local WASM
(?<=ID=)\d+

Result: "42"

PCRE2-8 · Local WASM
(?<=ID=)\d+

Result: "42"

Counterexample

Text "code=9"

JavaScript · This browser
(?<=ID=)\d+

Result: no match

Python re · Local WASM
(?<=ID=)\d+

Result: no match

PCRE2-8 · Local WASM
(?<=ID=)\d+

Result: no match

Recorded by running fixture FX-S06 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