Payment gateways › PRO
NMI Payment Settings
Take cards through NMI in its own secure card fields, sign in with an API key, and add Apple Pay, Google Pay and 3-D Secure. A PRO gateway. 7 parts.
Quick links
Where to find it:WP Admin › EasyCart › Settings › Payment › Network Merchants (NMI)
Connect
Keys and secure card fields
Where NMI is, and the two keys that connect it.
Where NMI lives
A PRO card gateway, set up in a side panel on Settings › Payment
no stored settingsNMI ( Network Merchants ) is a card gateway that many US and Canadian payment providers resell. It comes with WP EasyCart PRO and Premium. Shoppers pay by card on your own checkout page.
Open EasyCart › Settings › Payment, type NMI in Search gateways under Add or change a gateway, and press Set up on Network Merchants (NMI). Its settings open in a side panel. Press Save and turn on to make NMI the gateway on your Card payments line, or Save to keep it off for now.
Once NMI is connected, its line says how cards are taken and how the store signs in: Card entry reads NMI secure card fields or Card form ( cards pass through your server ), and Sign-in reads API security key or Username and password ( retired by NMI at the end of 2026 ). It also shows the result of the last key check, the wallets that are on and whether 3-D Secure is on.
API keys
A private security key, and a public tokenization key for the secure card fields
no stored settingsBoth keys come from your NMI merchant portal, under Settings › Security Keys.
Security key (private): create a private key with API permission and paste it here. It is how your store signs in to NMI. With a security key saved, the username and password are no longer used.
Tokenization key (public): create a public key with Tokenization permission. With it, shoppers type their card into NMI’s own secure fields, so card numbers never reach your server. That moves your store from PCI SAQ D to SAQ A-EP. It needs the security key, and your checkout page must use HTTPS.
Each save checks the security key with NMI. The panel then says NMI accepted the security key with the time of the check, or that NMI refused it, with NMI’s answer. A refused key usually means part of it was not copied, or it lacks API permission. If NMI could not be reached, check the Gateway address under Options and save again.
With a security key and no tokenization key, the panel warns Card numbers still pass through your server: add the tokenization key to switch to NMI’s secure card fields.
💡 Note: Add both keys. The security key alone keeps the older card form, where card numbers pass through your server; the tokenization key switches to NMI’s secure card fields, and Apple Pay, Google Pay and 3-D Secure need them.
Extras
Wallets, 3-D Secure and options
Apple Pay, Google Pay, checking cards with the bank, and the rest of the panel.
Apple Pay and Google Pay
Shown beside NMI’s secure card fields, so they need both keys
no stored settingsGoogle Pay shows to shoppers whose browser has Google Pay. Your NMI account must accept Google Pay; if a test payment is refused, ask your provider.
Apple Pay shows in Safari on Apple devices. Turn Apple Pay on in NMI’s merchant portal ( Settings › Apple Pay ) and add your site’s domain there. Switch Apple Pay on here and Domain to add in NMI shows that domain with a Copy button. WP EasyCart serves NMI’s domain verification file for you, so leave Domain verification file ( only if Apple Pay does not verify ) empty. Only if NMI’s portal will not verify your domain, open the file it lets you download in a text editor and paste it there.
Both wallets need the security key and the tokenization key. At checkout they sit above the card fields, with or pay by card between. After a wallet press the shopper places the order to finish, or chooses Use a card instead.
3-D Secure
Typed cards checked with the card’s bank before they are charged
no stored settingsCheck cards with 3-D Secure checks each typed card with the card’s bank through NMI Payer Authentication before it is charged. Most cards pass without the shopper seeing anything; some shoppers are asked to confirm with their bank.
Switch it on and Checkout key (public) appears. It is a public key with Checkout permission, from Settings › Security Keys in your NMI portal, and a different key from the tokenization key. 3-D Secure also needs both API keys, and NMI must switch Payer Authentication on for your account; it is a paid NMI service. Without the checkout key, NMI’s line says On, but the checkout key is missing and cards are not checked.
When a card cannot be checked, it is not charged. A shopper whose bank does not confirm the card is asked to try another card or contact their bank. If a checkout finds Payer Authentication switched off on your NMI account, the panel says so for a week, with the date: ask your provider to switch it on, or turn 3-D Secure off.
Options and test mode
Currency, a reseller’s gateway address, level 3 details, and NMI’s test mode
no stored settingsCurrency: the currency your merchant account charges in: USD, CAD, EUR or GBP.
Gateway address: leave it empty to use NMI’s usual address, secure.networkmerchants.com. If your payment provider gave you their own NMI address, such as secure.yourprovider.com, enter it as a host name. Every NMI call, the secure card fields included, goes to that address.
Your shipping postal code: the postal code you ship from, sent with each sale.
NMI processor ID: optional. Routes sales to a specific processor on your NMI account.
Summary commodity code: optional. Sent with level 3 card data.
Test mode, under Testing, sends each payment in NMI’s test mode, so no card is charged. It works with a live NMI account; a sandbox account is always in test mode. Turn it off before you open the store.
⚠️ Careful: Test mode takes no money. Turn it off and place one real order before you open the store. Diagnostics warns about a gateway left in test mode.
Good to know
Switching sign-in, and at checkout
Moving off the username and password, and what shoppers and your log see.
Moving from username and password to an API key
NMI retires username and password sign-in at the end of 2026
no stored settingsStores set up before NMI’s API keys sign in with an NMI username and NMI password. NMI is retiring that sign-in at the end of 2026. While your store still uses it, NMI’s panel opens on NMI login with that warning, and Settings › Payment shows NMI is retiring username and password sign-in at the top.
To switch:
1. In your NMI merchant portal open Settings › Security Keys and create a private key with API permission.
2. Create a public key with Tokenization permission too, for the secure card fields.
3. Paste them into Security key (private) and Tokenization key (public) under API keys, and press Save.
4. Check that the panel says NMI accepted the security key and that the line’s Sign-in reads API security key.
5. Place a test order, with Test mode on, before you take live payments again.
The username and password then move to Older login, marked Not used while a security key is saved.
Cardinal Centinel is gone. NMI’s older Cardinal Centinel option ran a version of 3-D Secure that the card networks have retired. A store that had it on sees NMI now charges cards without Cardinal Centinel on Settings › Payment and in Store Status; cards are charged through NMI Direct Post. Open NMI’s settings and save them to turn the old setting off, and use Check cards with 3-D Secure for 3-D Secure.
⚠️ Careful: NMI retires username and password sign-in at the end of 2026. A store still signing in that way needs a security key before then to keep taking card payments through NMI.
What shoppers see, declines and refunds
NMI’s card fields on your checkout, and NMI’s reasons in your log
no stored settingsWith both API keys saved, the card number, expiry and security code are NMI’s own fields, labelled Card number, Expiration ( MM / YY ) and Security code, in place of the store’s card inputs. They work on the classic checkout and the one-page checkout. On Place order the card becomes a one-time token, and only the token reaches your store. The fields need JavaScript: if they cannot load, the card is not charged and the shopper is asked to enable JavaScript and try again.
Declines. A declined card is not charged, and the shopper is told it was declined, as your Declined payment message in Settings › Checkout protection allows. Each payment writes one line to the gateway log in Settings › Log entries: NMI’s response and reason, the address and security code checks, the card brand and last four digits and the 3-D Secure result. Never the card number, a token or your key.
Refunds. A refund from the order screen goes to NMI, in part or in full. A full refund of a sale that has not settled yet, which NMI cannot refund, is voided instead. A refund NMI refuses shows NMI’s reason.
Keep going
Related panels
Every gateway, test mode and the gateway list.
The gateway log, with NMI’s reason for each payment.
Refunds that go back to NMI.
The checkout the card fields sit on.
Flex-Fees, such as a card fee.
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