Authorize.net is a payment gateway that processes credit card and electronic check transactions. It's a popular choice for businesses that want a traditional merchant account setup or already have an existing Authorize.net account they want to connect to CartOS.
What you'll need
To connect Authorize.net, you'll need an Authorize.net merchant account. If you don't have one, you can sign up at authorize.net. The signup process includes a merchant account application, which may take a few days for approval.
Once your account is active, you'll need two pieces of information: your API Login ID and your Transaction Key.
Finding your API credentials
Log in to your Authorize.net account at the Merchant Interface. Navigate to Account › Settings › API Credentials & Keys.
Your API Login ID is displayed on this page. For the Transaction Key, you'll need to generate a new one if you don't have it saved—click New Transaction Key and follow the prompts. Store this key securely; you won't be able to view it again after leaving the page.
Connecting Authorize.net
In your CartOS admin, go to Settings › Payments. Find Authorize.net in the list of payment providers and click Set Up.
Enter your API Login ID and Transaction Key in the corresponding fields. Select your environment—choose Production for live transactions or Sandbox for testing. Click Save to connect.
CartOS will verify your credentials. Once confirmed, toggle Authorize.net to Active to enable it at checkout.
Accepted payment methods
Through Authorize.net, your store can accept Visa, Mastercard, American Express, Discover, and JCB credit cards. Depending on your merchant account configuration, you may also be able to accept eChecks (ACH payments).
The specific cards you can accept depend on your merchant account agreement. Contact Authorize.net or your merchant services provider if you need to enable additional card types.
Checkout experience
When a customer pays with Authorize.net, they enter their card details directly on your checkout page. CartOS securely transmits the payment information to Authorize.net for processing. Customers stay on your site throughout the entire checkout—there's no redirect to a third-party page.
Transaction fees
Authorize.net charges a per-transaction fee plus a percentage of the transaction amount. There's also a monthly gateway fee. Exact pricing depends on your account agreement—check with Authorize.net for current rates. CartOS does not add any additional fees on top of Authorize.net's charges.
Refunds
When you issue a refund in CartOS for an Authorize.net transaction, the refund is submitted through the gateway automatically. For transactions settled within the last 120 days, refunds go back to the customer's original card. Partial refunds are supported.
For older transactions or situations where a card refund isn't possible, you may need to process the refund outside of CartOS directly through the Authorize.net Merchant Interface.
Address Verification (AVS)
Authorize.net includes Address Verification Service to help prevent fraud. AVS compares the billing address entered at checkout with the address on file with the card issuer. You can configure how strictly to enforce AVS matching in your Authorize.net account settings.
If legitimate orders are being declined due to AVS mismatches, you may need to adjust your AVS settings in the Authorize.net Merchant Interface under Account › Fraud Detection Suite.
Testing with Sandbox
Authorize.net provides a sandbox environment for testing. Sign up for a sandbox account at the Authorize.net Developer Center, then connect your sandbox API credentials in CartOS with the environment set to Sandbox.
Use Authorize.net's test card numbers to simulate various transaction scenarios. Once your integration is working correctly, switch to your production credentials to go live.
Troubleshooting
If transactions are failing, first verify your API credentials are correct and that you've selected the right environment (Production vs. Sandbox). Check that your Authorize.net account is active and in good standing.
For specific error codes, consult the Authorize.net Response Code Reference in their documentation. Common issues include AVS declines, insufficient funds, and expired cards—these are customer-side issues rather than integration problems.
If you're seeing timeout errors, it may indicate a temporary connectivity issue with Authorize.net's servers. Wait a few minutes and try again.