Regex Tester
private · runs in your browser
~ $ devkit:regex-test

Regex Tester

Test JavaScript regular expressions with match highlighting and capture groups. Long-running tests stop after one second; up to 1,000 matches are shown.

Test text
Result
Run a test to highlight matches.

How to use Regex Tester

  1. Enter a JavaScript regex pattern without surrounding slashes, and set flags such as g, i or u.
  2. Paste test text and choose Test. Inspect highlighted matches, character indices and capture groups.

Example

Pattern: (?<word>[a-z]+)
Flags: g
Text: abc 123 def
Matches: abc at index 0; def at index 8

Details and limitations

Uses your browser's JavaScript regex engine, not PCRE or Python syntax. Without g, only the first match is returned. Tests run in a worker and stop after one second. Results are limited to 1,000 matches; input limits are 200,000 text characters and 10,000 pattern characters.