We currently host about 40 copies of an application on IIS, each of which belongs to a different customer with a different Authorize.Net account. Each copy of the application has its own Application Pool, but several copies have multiple Authorize.Net accounts associated with them depending on the type of transaction. The application was originally written years ago and posts directly to the AIM method, but we are interested in upgrading to the C# DLL.

In the implmentation instructions, the code begins with:

ApiOperationBase<ANetApiRequest, ANetApiResponse>.MerchantAuthentication = new merchantAuthenticationType() {

    name = "API Login",
    ItemElementName = ItemChoiceType.transactionKey,
    Item = "Transaction Key",
};

I believe it's the case, but I'd like to verify that setting that propery will only apply to the current application copy and current request and not change anything in a global manner, so that it's safe for us to use the DLL in the hosting situation described above, especially where one copy of the software may be making multiple concurrent transactions on different Authorize.Net accounts.

If that is not the case, is there an alternate way of providing the authentication directly with the request so that we can move to the DLL?

Thanks in advance for the help!