Hi- thanks! I open sourced the code so that no one is locked into the service. You can run your own instance if you like very easily.
If it becomes very expensive for me, I'll try to just operate it at close to cost. I don't think this is a huge market, and I just made this as a weekend project because I needed something like it and thought others might find it useful.
Also, the site says you get up to 30,000 verifications for free, so that puts some cap on how expensive this could be.
Does this help you trust it?