Ask HN: How to make an Amazon Web Service style billing ? | Hacker News Reader

Ask HN: How to make an Amazon Web Service style billing ?

4 pointsXixi4 comments

I have to admit that I like pay-per-use style billing, where you pay exactly for what you are using, providing it's cheap. So I would like to use that kind of pricing scheme for my startup (www.assemblive.com, currently in private beta, pretty soon public).

I was wondering if some of your startups are using that kind of billing, and, very pragmatically, how did you implement it ? Are there some providers (like Paypal, Amazon, etc.) that offer that kind of payment scheme, where you just bill for actual usage at the end of the month ? I might be a bit naive, but it would seem to me that's it's basically like a subscription, but with a different amount each month...

From the end user point of view, I'd like them to be able to allow the payments just once. And then they just use the service as much as they want and don't have to do anything anymore regarding payments.

Tarsnap works with a prepaid usage-based billing model; every day at 00:00 UTC a cron job looks at how much storage people are using and processes the server logs to figure out how much bandwidth people used over the past 24 hours, and throws the numbers into Amazon SDB. Some time later, users' current account balances are updated.

When people connect to the Tarsnap server, it queries SDB to get the user's current balance and any payments they've made since the balance was last updated; if the balance is below zero, it sends back a "send more money" error message.

I considered taking the AWS approach of adding up usage and charging credit cards at the end of each month, but this wouldn't work for two reasons: 1. Half of the people using Tarsnap spend less than $0.30/month, so I'd lose most or all of the money in credit card processing fees; and 2. Dealing with bogus/expired/cancelled/etc. credit cards is not something I want to worry about.

That's actually exactly what I don't want to have to deal with: bogus/expired/cancelled/etc. credit cards. Hence I'm looking for some kind of middle man.

But that's actually a solution I'm looking at: prepaid usage-based.

I highly recommend Braintree. Variable monthly billing is very different from monthly billing from the card processor viewpoint. Most providers will let you schedule recurring payments, but only fixed ones. Braintree let you do variable billing, without needing to go through the PCI process, because the credit card information never touches your servers.

It seems interesting, but US only, and my startup is in France...

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