Foxy connects to NMI with a private security key. Here's how to create one and add it to Foxy (these instructions are current as of 6th October 2026. Please let us know if your portal looks different):

1. Log into your NMI account's Merchant Portal as an admin user. Only admin users can create security keys.
2. Click (on the left) Options→Settings→Security Keys and select Add a New Private Key.
3. Name the key so you'll recognise it, such as “Foxy Commerce”, select the user it belongs to, and give it the API permission.
4. Create the key and copy it.
5. Open your Foxy admin's and go to Settings > Payments, and select your payment set. Then select to add a new payment method.
6. From the options, select NMI (Native Integration).
7. Enter api_key into account username and paste the security key into transaction key and save the changes.
8. Test.

NMI is retiring username and password logins for its API by the end of 2026. From 15 December 2026, Foxy's NMI (Native Integration) will work only with an NMI security key. If you're set up with a username and password, create a security key as in the first four steps above. Then update your NMI (Native Integration) settings in Foxy: replace the username with api_key and the password with the security key. Do this for every payment method set that uses NMI, and for test credentials as well as live ones. Test afterwards to confirm payments still go through.

After 15 December 2026, stores still using a username and password will have their NMI payments declined.

Note: If you get an error about “Overriding Duplicate Threshold is not allowed” you'll need to contact your merchant account provider to have them remove that restriction.

As always, test with a live card before you assume things are working.

Contact your merchant account provider to obtain a test account as NMI support will be unable to provide you one.

Otherwise, you can use testing credentials found below. Keep in mind, your production gateway account may have settings that differ from the sandbox/developer account below.

• Username: demo
• Password (Transaction Key): password

These card numbers will only work in Test Mode.

• Visa: 4111111111111111
• MasterCard: 5431111111111111
• Discover: 6011601160116611
• American Express: 341111111111111
• Expiration: 10/35
• CVV: 999

If you get a “The processor response format is invalid” error, you can contact NMI support to find out the reason, but you may need to get ahold of the processor directly for a solution. In some cases the processor can return “INV CVV2 MATCH” so it results in a decline response from the gateway. This generally means that the card holder entered an incorrect Card Security Code, and the processor or Bank has rejected the transaction.

If you get a Response Reason Code: 122, there are a couple possible issues there.

Firstly, you can try to update your payment gateway settings in FoxyCart. Make sure the Security Key entered into the Foxy admin correctly matches the value shown from the NMI Security Key page in the Settings section. Also confirm that the username is set as api_key.

Other possibilities include:

• The transaction amount is greater than the max allowed ticket amount set for your NMI account. To change that amount, your Merchant Service Provider's customer service team will need to approve that increase.
• There is a duplicate transaction check at the gateway that is set to a number of seconds (default is 120). Talk to your account rep to set it to 3 to match what NMI saw as the setting at Foxycart coming through, and also enable the option to allow for the merchant to override for the duplicate check. (Note: This is feedback from a user. Please check with your account rep to discuss this.)

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