Go Regex Tester

Test a regex with Go's regexp package (Go 1.27.1 as WebAssembly), loaded on request.

Go's regexp package, in this browser

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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.
(?P<name>...)
Named capture.
(?=...)
Unavailable in Go regexp.
i · m · s
Ignore case / line anchors / dot-newline.
Browse the full reference

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Go 1.27.1 regexp

Not available in Go regexp · Local WASM: x · ignore pattern whitespace; a · ASCII-only classes; u · Unicode; v · Unicode sets; y · sticky; J · duplicate names.

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

Test text

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Verified Fixture FX-G04

What it does

Test a regex with Go’s regexp package (Go 1.27.1) compiled to WebAssembly.

How to use it

  1. Load the Go 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

As written

Text "ba"

JavaScript · This browser
a*

Result: "", "a", ""

Python re · Local WASM
a*

Result: "", "a", ""

PCRE2-8 · Local WASM
a*

Result: "", "a", ""

Go regexp · Local WASM
a*

Result: "", "a"

Recorded by running fixture FX-G04 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