How do I obtain my Authorize.Net API Login ID and Transaction Key?

To obtain the API Login ID and Transaction Key: Log into the Merchant Interface at https://account.authorize.net.

Click Account from the main toolbar.
Click Settings in the main left-side menu.
Click API Credentials & Keys.
Enter your Secret Answer.
Select New Transaction Key.
Note: When obtaining a new Transaction Key, you may choose to disable the old Transaction Key by clicking the box titled, Disable Old Transaction Key Immediately. You may want to do this if you suspect your previous Transaction Key is being used fraudulently.
Click Submit to continue. Your new Transaction Key is displayed.

If the Disable Old Transaction Key Immediately box is not checked, the old Transaction Key will automatically expire in 24 hours. When the box is checked, the Transaction Key expires immediately.

Be sure to store the Transaction Key in a very safe place. Do not share it with anyone, as it is used to protect your transactions.

The system-generated Transaction Key is similar to a password and is used to authenticate requests submitted to the gateway. If a request cannot be authenticated using the Transaction Key, the request is rejected. You may generate a new Transaction Key as often as needed.