❗️

Never Use Real Data

Never use real credit card or bank account information when testing.
The gateway provides several methods for testing transactions without sending any data to the credit card or ACH processor.

Sandbox Account

How it works

• Log in to guide.nmi.com to retrieve Sandbox Keys or access the Sandbox Partner and Merchant Portals.
• Build and test your integration.
• All transactions are simulated; no charges are processed.

Best for

• Full integration testing before going live.
• Safe development without impacting production accounts.

Test Transaction

How it works

• Set test_mode to "enabled" on a single transaction.
• Use one of the Test Credit Card Numbers with expiration date 10/25.
• Processes only that transaction in test mode; all other account transactions remain normal.

Example

{
  "security_key": "your_live_key",
  "test_mode": "enabled",
  "ccnumber": "4111111111111111",
  "ccexp": "1025"
}

Best for

• Testing in a development environment while your live site processes real transactions.
• Quickly validating a specific payment scenario.

Notes

• Only available on live accounts (not supported in Sandbox).
• To view in reporting, temporarily toggle account to test mode.

Demo Account

How it works

• Use the Payment Gateway Demo Account — always available, no setup required.
• Security key:

6457Thfj624V5r7WUwc5v6a68Zsd6YEm

• Completely isolated from your own accounts.

Best for

• Quick tests, training sessions, or demos.
• Shared testing between teams or external partners.

Notes

• Fully sandboxed—no actual processing occurs.
• Safe to embed in code samples or documentation.

Test Mode

How it works

• Toggle any merchant account into test mode.
• All valid credit cards will be “approved” without actual charges or processing.

Best for

• Testing all transactions in a controlled environment.
• Bulk or repeated tests.

Notes

• While in test mode, all transactions are simulated.
• Avoid enabling in a live production environment serving customers.

Test Values

Card and ACH

Triggering Specific Responses

3D Secure (3DS) in Sandbox

Not Enrolled – Frictionless Flow

Cards return Enrolled: "N", skipping authentication.

Expected:

• cardholder_auth: "attempted"
• CAVV: (empty)
• ECIFlag: "07" (Not enrolled)

Frictionless Authentication Flow

Cards return Enrolled: "Y" with CAVV present.

Expected:

• cardholder_auth: "verified"
• CAVV: "mock_cavv_0002_1234567890"
• ECIFlag: "05" (Authenticated)

Challenge Flow

Triggers a 3DS challenge with mock interaction.

Expected:

• Enrolled: "Y"
• PAResStatus: "C" (Challenge required)
• ECIFlag: "02" (Challenge required)
• User sees a mock challenge interface.

Challenge Actions