After logging into your Authorize.net account, click Account. This screenshot below shows the 3 areas you need to access.
First, click API Login ID and Transaction Key. This will give you a series of letters and numbers you need to copy and paste into CrossPostIt under the Authorize.net Login ID. Next, it will ask for a password so you can get the Transaction Key to paste into CrossPostIt.
The next page you need to access is the MD5-Hash. In CrossPostIt, the screenshot above shows “test”. Copy the code in CrossPostIt and then go to Authorize.net to paste it into the page shown below.
Last is the Relay Response URL. In Authorize.net, click Relay Response and then enter the URL shown in CrossPostIt.
Your store is now setup! Please click here if you need assistance creating an Authorize.net account.