I’m personally releasing a Tor Hidden Service to check whether a Grin Wallet is reachable or not. Users just need to enter the HTTP Address; the service will be online for a while until HTTP Transaction is finally deprecated by Grin. The service is available only through Tor and no logs are stored in any manner.
The Tor URL is this: http://grinchck.ahcbagldgzdpa74g2mh74fvk5zjzpfjbvgqin6g3mfuu66tynv2gkiid.onion/
Also the code in available on Github if you want to hosted by yourself: https://github.com/davidtavarez/grinaddresschecker.
I’m using the Grin++ logo because I like the logo… a lot!