Engine	Description	Online Testing
	re module	(not available)	metadata
	Package regexp	Beta	metadata source status uptime
	Text.Regex	Beta	metadata source status uptime
	java.util.regex.Pattern	Running	metadata source status uptime
	RegExp object	Running	metadata source status uptime
	String Regular Expression Operators	(not available)	metadata source
	System.Text.RegularExpressions.Regex	Running	metadata source status uptime
	perlre	Beta	metadata source status uptime
	PCRE Functions	Beta	metadata source status uptime
	regexp_* functions	Beta	metadata source status uptime
	re module	Running	metadata source status uptime
	Regexp class	Beta	metadata source status uptime
	Regex crate	Beta	metadata source status uptime
	regexp command	Beta	metadata source status uptime
	XRegExp object	Beta	metadata source status uptime

Check out the API specs if you want to add support for another engine

See the different options supported by each engine.