NMI is one of the most-used gateways behind high-risk MIDs and reseller programs. It does not appear on Shopify's default approved third-party gateway list, so Shopify native checkout will not offer it as a payment option. Own-domain checkout via CascadeCheckout wires NMI in directly: buyers still land on your Shopify storefront, checkout runs on your subdomain, capture goes through NMI's Customer Vault + 3DS2 flow.
Operator gets an NMI MID from a reseller — Fluid Pay, iTransact, Payment Cloud, Payline, or direct through Network Merchants. Reseller sends over API keys, gateway ID, tokenization guide. Operator opens Shopify → Payments → looks for NMI. Not there. Realises Shopify's native checkout does not accept NMI directly. Default workarounds are a custom Shopify Ruby app (weeks of engineering) or switching stores.
Own-domain checkout is the shorter path. Point the Buy button at checkout.your-brand.com. On our page, when the buyer enters their card, we tokenize with NMI's Customer Vault, capture through NMI's transaction API, and write the resulting Shopify order via Admin API. Order lands in Shopify with the standard buyer, line items, discount and shipping.
API key + username. If it is a whitelabel NMI reseller, we accept the reseller endpoint URL too.
Add a second MID as route 2 — offshore acquirer, a second NMI reseller, or a mainstream gateway. Cascade rotates on NMI-specific decline codes.
Captured order writes to Shopify Admin tagged [cascade:nmi]. Refund, fulfillment, apps all work normally.
NMI reseller vs direct. Doesn't matter for the integration. NMI's platform powers dozens of whitelabel resellers, and they all expose the same core API surface. Bring whatever creds your reseller gave you.
NMI is not on Shopify's default approved third-party gateway list. Native Shopify checkout will not present it as a payment option. Own-domain checkout via CascadeCheckout wires NMI in without touching Shopify's approved list.
Customer Vault tokenization, 3DS2 authentication, card capture, refund, void, and standard NMI decline codes. The cascade uses NMI decline responses to decide whether to rotate to a backup route.
Either works. NMI's whitelabel platform is used by dozens of resellers (Fluid Pay, iTransact, Payment Cloud, etc). CascadeCheckout speaks the NMI API, so any reseller MID that surfaces standard NMI endpoints connects the same way.
Yes. Common pattern is NMI as route 1, offshore acquirer as route 2. If NMI declines above threshold, route 2 captures without buyer-visible failure.
Bring NMI keys + Shopify domain. We do the wiring.
High-risk processor → · Payment gateway cascade → · How it works →
CascadeCheckout