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Regex Tester & Builder

Dev

Build and test regular expressions live: match highlighting, capture groups, replace preview, flags and a starter library.

2 matches
Matches highlighted
Contact ops@shellquest.io or admin@example.com.
Server 10.20.30.42 returned 503 at 2026-06-20 14:03:11.
Docs: https://shellquest.io/tools/ — request id 7a1c9f2e-3b4d-4e5f-8a9b-0c1d2e3f4a5b.
Match details
match 1 @ index 8ops@shellquest.io
match 2 @ index 29admin@example.com
Quick reference
\dany digit (0–9)
\wword char (a–z, 0–9, _)
\swhitespace
.any char (except newline)
^ $start / end of line
\bword boundary
*0 or more
+1 or more
?0 or 1 (optional)
{n,m}between n and m times
[abc]any one of a, b, c
[^abc]none of a, b, c
(…)capture group
(?:…)non-capturing group
a|ba or b

Uses your browser's native JavaScript regex engine (the same one Node uses) — patterns run locally and nothing is sent anywhere. PCRE-only features like recursion or possessive quantifiers aren't supported.

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