- Is this a real Ruby regex tester if it runs JavaScript?
- Matching runs on JavaScript's RegExp engine, which shares its Perl-derived core syntax with Ruby's Onigmo — character classes, quantifiers, anchors, alternation, groups, lookarounds, and (?<name>) named captures all behave the same. The compatibility table on this page covers the exceptions (flag meanings, POSIX classes, \A/\z). For patterns using Ruby-exclusive syntax, do a final check in irb.
- Why does my pattern work here but not with Ruby's ^ and $?
- In Ruby, ^ and $ always match at line boundaries — there is no toggle. If you're validating a whole string (like user input), use \A and \z in Ruby, otherwise "evil\ninput" can sneak past your validation. This is a well-known Rails security pitfall: format validations should use \A…\z, not ^…$.
- What's the Ruby equivalent of the g (global) flag?
- Ruby has no g flag — you choose per method call: scan returns all matches (like g), while =~ and match find only the first. gsub replaces all occurrences; sub replaces only the first.
- Is this a Rubular alternative?
- Yes, for the common case — live testing with capture-group display — plus a code generator Rubular doesn't have. Rubular runs an actual Ruby engine, so use it (or irb) as the final check for Ruby-exclusive syntax like [[:alpha:]] or \h.
- Is this tester free and private?
- Yes — free, no signup, no limits, and 100% client-side: patterns and test strings are processed in your browser and never sent to a server.
