Authorize.net, SIM (php), and adding variable tax for in-state purchase

Question

I am helping a client with a simple "shopping cart" using SIM through authorize.net. Limited number of items, they don't change, really don't need a full-on shopping cart, EXCEPT that we must charge tax to Colorado customers (and we'd like to vary the shipping method, based on whether they need it fast or slow or international). Obviously the tax rate varies depending on where you are in the state. I'm sure that MANY others have faced this issue and that there is an answer, I presume in the form of a preprocessing script that can generate the item + tax + shipping, which is then submitted to authorize.net.

For the likes of this forum this is probably pretty basic, but that's where I'm at.

TIA

Answer 1

easiest way is to go with a solution like shopify or one of the other fine services or carts that can automatically handle taxation rates...

you can also use a web service to determine the tax rates for any jurisdiction in real-time:

• FastTax
• zip2tax

are a couple web services... i think some companies can also give you a data dump.

during checkout, query the web service and add the tax amount if the shipping address is in CO.

the state tax rate would be 2.9%, official city/country tax rates here:

Search: https://www.taxview.state.co.us/QueryTaxrates.aspx?selected=1

PDF: http://www.colorado.gov/cs/Satellite?c=Document_C&cid=1185353127906&pagename=Revenue%2FDocument_C%2FREVXAddLink (enable popups to view)

Answer 2

For something like this, I would usually recommend Shopify. But, if you want to go with Authorize.NET, how about looking at AIM instead of SIM. http://SharpAuthorize.com makes it easy.