This is a simple repository to check if a language / regex engine is vulnerable to ReDoS. If you've written a regular expression with catastrophic backtracking, you may be vulnerable to DoS via a text input that exploits that regular expression.
redos.json contains a collection of vulnerable regular expressions, and text inputs that exploits the vulnerabilities.
The "ReDoS Checks" action 
executes simple implementations to execute the vulnerable regular expression on the dangerous input, timing out if it takes too long.