We launched our company with a landing page where people would have to pay for a $30/mo recurring subscription upfront before they could try anything (no free tier, no trial). After paying, they would land on a page saying "you will get your API key in the next 30 mins".
Every signup would send us an email saying a "new customer signed up". I built muscle memory to check my email constantly, no matter what I was doing. Whenever a new email would come in, I would rush to get them their API key by email. This included
- running back from a party on sat night in Amsterdam
- waking up in the middle of the night when the notification would go off loudly (many times)
For the first 1-2 months of the product, we were getting a signup a day on avg. Getting the new customer for the day was a huge win. At ~5 months, we hit the point where we were getting multiple new customers every hour. That's when we automated.