Authorize and save the method
Reserve funds now and capture later, while saving the method.
Prepare the order
Use matching sandbox merchant credentials and a fresh component token. Resolve the amount on your server. Obtain consent to save the payment method and confirm Customer Vault is enabled. online
Submit from your server
This request uses the REST Payments API. Replace placeholders and the example amount with the authorized test order. POST /api/v5/payments/auth HTTP/1.1 Host: sandbox.nmi.com Authorization: <sandbox-private-merchant-key> Content-Type: application/json { "amount": 10.0, "payment_details": { "payment_token": "<fresh-sandbox-token>" }, "customer_vault": { "add_to_vault": true, "id": "CUST-EXAMPLE-001" } }
Record the outcome
Check the gateway result, not only HTTP success. Store the payment ID and returned vault ID against the correct merchant and customer. An authorization is not a capture. Capture the existing payment when fulfillment is ready.
Verify failure handling
Test approval, decline, and a lost response. Keep ambiguous attempts unresolved until investigated; do not create another charge automatically. Handle uncertain outcomes