Show HN: Reduce bounce rate for transactional emails

I've run a bunch of side projects in the past and I always had problems with people signing up with fake email accounts for what ever reason. Then you send them a welcome email, it bounces, this happens many times and you find yourself with a bad reputation or low sender score.

I built this quick app last weekend and I've started using it for one of my projects. There are other services like this but I need it to be cheap, really cheap.

Appreciate any feedback on this or interest to try it out in production.