That’s a great question. I’ve been trying to decide if that’s the best way to go. I’ve built a metered plan internally that has the following tiers:

• 0 - 100 PDFs: $0.20 per PDF

• 100 - 1,000 PDFs: $0.10 per PDF

• 1,000 - 10,000 PDFs: $0.05 per PDF

• 10,000 - 100,000 PDFs: $0.02 per PDF

• 100,000+ PDFs: $0.01 per PDF

I don’t like that the customer is invoiced at the end of the month, instead of paying at the beginning. I was worried that someone would generate a lot of PDFs, and then their card would be declined. I might have spent a lot of money on hosting and wouldn’t be able to collect payment. For brand-new customers, I could also collect payments at certain intervals (E.g. $50, $100, $500, $1000, $5000.) After 2 months, I could trust them more and just have one charge at the end of the month.

I could continue to have monthly plans with quotas, and add the pricing tiers based on usage. If a customer knows that they will generate at least 100 PDFs per month, then they could pay a discounted rate at the beginning of the month, and save 30% on the first 100 PDFs.

I was also thinking that customers could buy “credit packages” at a discounted rate. This would useful if they are running a one-time batch job, and wanted to get a discount for the next 1,000 PDFs. The credits would also roll over to the next month, and I don’t think I would set an expiry date. I paid for some credits on KeyCDN, and it was really annoying when they expired after a year.

I’ll continue to think about this and A/B test different pricing over the coming months.