A question which sometimes was asked by our customers was: “Does the payment method Authorize.net in your themes use SIM oder AIM?

SIM stands for “Server Integration Method”
AIM stands for “Advanced Integration Method”

To answer this in one brief sentence: Currently we are using SIM.

What does the customer experience when he pays via Authorize.net SIM?
At the last step of the checkout process he presses the famous button “Pay now”. The customer is sent now away from your shop website to a secured Authorize.net entry form. There the customers fills in all the necessary CC infos and presses again a payment button.
Authorize.net processes the transaction and sends the customer together with a special payment signal back to your website. Based on the “payment status” Authorize.net provides, the customers sees a “Thank message” or a “something went wrong message” (like: not sufficient funds on CC).

What would the customer experience if he would pay via Authorize.net AIM?
At the last step of the checkout process he presses the button “Pay now”. Then he is not sent away from your website but rather to a different page of your website. There he fills in his credit card information and there he clicks on a “Continue” button. And… then he sees a “Success” or “No success because…” message.

Something very important happened between the last two steps. Your website sent the CC-Data via a hidden CURL call to Authorize.net – the result of the transaction is sent back again in the background.
Like this the customer has the feeling he never leaves the website.

So AIM would be better?
Seen from the customer experience there is no question about it. AIM is more seamless.
However SIM has one big advantage. What if some customer accuses you that you stole his CC number? Well in this case you can very easily answer with: “My friend, you filled in your CC info on a page of Authorize.net and not on me website”. Ok – this is a bit of far-fetched scenario but theoretically possible.

Future plans
I’m sure you guessed it already: we are planning to implement also the AIM method…