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Regex Tester

Test a bounded regular expression against local text, inspect match offsets and captures, then export the report.

Match explorer29 chars
A bounded JavaScript-style pattern, without lookarounds or backreferences.
g i m s u
Up to 20,000 characters. The preview shows at most 1,000 matches.
Live match explorer Ready
3 matches · choose one to inspect
Offset
0–3
Full match
"Ada"
Captures
None
Processed on your device

How it works & useful details

Find matches with guardrails

Enter a JavaScript-style pattern and optional g, i, m, s, or u flags. The explorer scans local test text and lets you inspect captured groups and character offsets.

For predictable browser responsiveness, lookarounds, backreferences, repeated alternatives, and repeated groups containing repetitions are refused. A refusal is not a security verdict for any pattern; use a dedicated runtime policy for untrusted regular expressions.

Private, bounded text processing

Code and markup stay as inert text in this browser. These tools do not execute JavaScript, render HTML, load URLs, install packages, contact registries, or save what you paste.

Regex patterns are limited to 500 characters and test text to 20,000 characters. Formatters and package inspection accept up to 100,000 characters; exports are capped at 200,000 characters.