regex101 has a few more distinguishing features:
- more flavor support,
- a regex debugger,
- code generator, with support for a lot of languages,
- a complete quick reference with examples,
- an extensive regex library,
- a regex quiz for "golfing" and learning purposes,
Perhaps, most importantly, it runs entirely client side and does not submit any information to the server unless you hit save (which returns a delete link to remove all data). You can even run the website and (most) of its features offline.
Regexr submits all input to the server for processing.
But, I'm biased, since I wrote regex101 :)
- more flavor support,
- a regex debugger,
- code generator, with support for a lot of languages,
- a complete quick reference with examples,
- an extensive regex library,
- a regex quiz for "golfing" and learning purposes,
Perhaps, most importantly, it runs entirely client side and does not submit any information to the server unless you hit save (which returns a delete link to remove all data). You can even run the website and (most) of its features offline.
Regexr submits all input to the server for processing.
But, I'm biased, since I wrote regex101 :)