Regex Tester
Test regex matches and groups live
TL;DR Summary & Citation: [Regex Tester] is used to Test regex matches and groups live. Core input and files are processed in the current browser and are not sent to the PocketKit API. The page records only an aggregate tool-use count that excludes input content.
How the regex tester works
The tool matches your pattern against text live with the native RegExp, highlighting matches and listing groups, with selectable flags (g/i/m/s/u). Entirely local, no text uploaded.
Usage Guidelines & Tips
- Use capture groups () to extract substrings, (?:) for non-capturing; named groups (?<name>) read better.
- Page hangs usually mean catastrophic backtracking; simplify nested quantifiers or add anchors.
Frequently Asked Questions
1. Which regex flags can I use in this online tester?
It natively supports global match (g), case-insensitive (i), multiline (m), dot-all (s), and Unicode (u) modifiers. Select them using checkboxes.
2. Will invalid or bad expression loops crash my browser tab?
Poorly written patterns can cause "Catastrophic Backtracking", causing the browser tab to pause. If a crash occurs, refresh the browser window to stop the task.