I am pretty sure the OutCast3k coinbin site is safe. It won't sign Bitcoin Cash HODL transactions though.
I wasn't referring to coinb.in tool but txid.io tool which is a fork of OutCast3k's coinbin
there is no info about the creator (on the site) or its Ann on bctalk forum,
it won't let me create double spend (unsigned raw) tx without inputting private key
That txid.io was mentioned to me a few weeks ago on Reddit, but that thread is gone now. It had a few bug fixes and fixed a couple of problems. Their HODL stuff doesnt work though, so I incorporated their fixes into my site.
I can't find anything on it on Github. Don't use that that double spend page, I absolutely don't trust it. You will notice I didn't use it in my site.
BTW, I created a double spend by hand a few days ago when a 256 byte transaction refused to go through even though it had a $17 fee. I wasn't able to send the double spend to any of the miners without a duplicate tx error though. I finally did a child pays for parent tx using the change. Cost me another $72 fee to get it to confirm.