DEVELOPER UTILITIES / LOCAL TOOL
Regex Tester
Test patterns with clear match highlights.
HOW IT WORKS
A pattern against real sample text
JavaScript RegExp evaluates the selected pattern and flags, then reports each match with its index.
Limits to keep in mind
Catastrophic backtracking can freeze a tab, and JavaScript syntax differs from other regex engines.
A PRACTICAL WORKFLOW
Use the result carefully.
01Enter a pattern on the first line and flags on the second line. Matches are tested against a sample string.
02Run the utility and inspect the complete output.
03Start with small sample text and avoid running unknown complex patterns against large input.
COMMON QUESTION
Why do matches change with the g flag?
The global flag asks the engine to continue finding matches after the first one.