How can I sell data on demand?

January 30, 2007 2:05 PM

I want to sell bits of on-demand data via my home computer and hosted website. What would be a good scheme for doing this without serving up data before it's been paid for?

For all practical purposes, just assume I sell files with historical stock info. As it is, this is a very low-volume operation with maybe no more than one transaction a day, and probably wouldn't generate more than $100-200 a month.

Theoretically my home office computer would monitor for customer orders. If it sees an order, a script would assemble the data off a 500 GB mass storage drive I have and then FTP it to my server, then notify the customer with an email with the filename. Technically this is not a big deal and I know how to do it; I am a programmer by trade.

The problem is that I don't know how to go about making sure the order is paid for and has been authorized. How could my scripts check that the order has been paid for? I don't want people putting in bogus credit card numbers and loading up on free data, or re-using authentication info to get extra data.

Is there a non-ripoff gateway of some kind that might help here without a big expensive account setup? I've seen that Paypal has a functionality where it offers shareware downloads only after a payment has been made. Can this do anything for me?

I already have a merchant account with Cardservice but all transactions are done on a pinpad terminal I have, and I don't think it's helpful here. My system doesn't need to be airtight... there would be a lot of manual monitoring of the system and losing data due to fraud is just a pisser and not a big deal.

posted by stam_broker to computers & internet (7 comments total)

I did something like this via paypal, I used their payment authentication service. Essentially, I sent the customer to paypal, where they pay, with information about what they're paying for, an ID, etc. When the payment clears, paypal opens a page on MY site with a little info, which I send back to THEIR site to verify it (this prevents a 3rd party from gaming me by opening the page on my site). So, I didn't even have special links of ftp directories or anything, if they tried to download a file that they had not paid for, then simply it wouldn't allow them to.
posted by RustyBrooks at 2:25 PM on January 30, 2007

Payloadz
posted by davebush at 2:32 PM on January 30, 2007

I checked out Payloadz, but it wasn't porn. Disappointing.

I second the Paypal suggestion (everyone trusts Paypal) but if you have a Cardservice account already, you're probably only a step away from a card-not-present service that you can use to validate and take $ online already. As a programmer, you should be able to install their libraries and wire something together in an afternoon. All the tx providers have "callbacks" that you can use to generate your one-time-download link.
posted by rokusan at 3:32 PM on January 30, 2007

I had no idea why I didn't put 2 + 2 together, but I thought about what RustyBrooks said and I realized any old shopping cart going to Paypal (I use mals-e) works. I can just capture the "Notification of Payment Received" email and process the request from that. I can probably run a few checks to make sure it isn't forged, but that's the ticket.
posted by stam_broker at 3:34 PM on January 30, 2007

I second the Paypal suggestion (everyone trusts Paypal)

Not everyone.
posted by davejay at 4:41 PM on January 30, 2007

The notification of payment received email might be OK, but their actual automatic verification system is not too hard to implement, and I think there are actually sort of little libraries for it. I made one for my web server (AOLServer) which I've used for many clients.

Lots of people have a beef with Paypal. They gave me some grief once. I got my money eventually.
posted by RustyBrooks at 4:52 PM on January 30, 2007

I setup Paypal IPN system in conjunction with Linklok and it worked great.
posted by bleucube at 5:11 PM on January 30, 2007