Regex Tester (.NET) PRO
Try a regular expression against sample text, see every match with its named and numbered groups, and preview replacements — using the same engine as C# and .NET.
Flags: i ignore case, m multiline, s single line, x ignore pattern whitespace, n explicit capture. Ctrl+Enter runs.
How to use it
- Enter the pattern and optional flags (i, m, s, x, n).
- Paste the test text and, if needed, a replacement like ${year}/${month}.
- Click Test (or Ctrl+Enter) to list matches and groups and see the replaced text.
Frequently asked questions
Why did my pattern time out?
Patterns like (a+)+ can backtrack exponentially. Each run stops after one second; make quantifiers more specific or use atomic groups.
Is .NET regex the same as JavaScript regex?
Mostly, but .NET adds features like named groups with (?<name>), lookbehind of any length and balancing groups. This tester uses the real .NET engine.
Is this tool free?
It's part of Engixy Dev Pro. Everyone can see the page; running it needs a Pro subscription, which you can cancel anytime.