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Getting Started with the NMI Payment Gateway

Updated

Table of Contents

Overview

This guide is for partners and merchants who are new to our payment gateway. Whether you're evaluating our platform or preparing for integration, we provide flexible testing options to help you get started quickly and confidently.

What is Pathfinder?

Pathfinder is our free sandbox environment. It allows you to explore our platform, test payment flows, and integrate with our APIs — all without processing real transactions.

This is ideal for:

  • Partners who want to demonstrate capabilities

  • Merchants evaluating our solution

  • Developers testing integrations before going live

How to Create a Sandbox Account (For Partners & Merchants Who Haven’t Signed Up Yet)

If you don’t have a live account with us yet, you can request access to our sandbox environment to try out the portal.

Please visit our www.nmi.com website → Click on Developers → Explore Sandbox.

First Time Signing In?

  1. Enter your email address.
  2. You’ll be prompted to provide your First Name, Last Name, and Company Name.
  3. Agree to the Terms and Conditions.
  4. Then, check your email for a login link.

Already Have a Sandbox Account?

  1. Enter your email address and click the login link sent to your inbox.
    Or, select Continue with Google to sign in immediately.

Once logged in, you’ll have access to use cases, integration guides, partner test keys, and a default merchant test key. You’ll also be able to test payments, onboard merchants, run reports, and unlock even more capabilities.

We’re continuing to expand what Pathfinder can do — keep an eye out for new tools and enhancements.

Testing Options for Registered Partners & Merchants

If you’re already signed up with the NMI gateway, you can access additional testing tools for merchants. Check out our articles on Standard, Mobile, and Test Merchant Accounts, and learn more about using the Test Mode option for live accounts.