Develop your hosted payment gateway integration

A hosted payment simulator built in Sinatra is available here. Follow the instructions available on the GitHub repository or below to test the simulator. This should give you a good idea of how Hosted Payment integrations work.

To run a test transaction with the Hosted Payment Simulator:

1. Add a payment gateway or change the “Redirect URL” of your gateway to https://offsite-gateway-sim.shopifycloud.com/.

2. Your gateway will now be available in your development store (see "Creating a development store") under the Credit Cards drop-down list or Alternative Gateways drop-down list. Find it and activate it using these credentials:

   • Username - any non-empty value

- Password / HMAC Key - iU44RWxeik

This gateway will now be available in your development store Shopify Checkout and will redirect customers to https://offsite-gateway-sim.shopifycloud.com/.

1. Complete a test purchase on your shop. If you don't have any products in your test store, then you might need to add one before you can complete a test purchase.

At the end of checkout you should be redirected to the simulator. This will let you get familiar with the various redirects and callback.

All requests and responses must be signed/verified using HMAC-SHA256 where:

• key is a value known to both the Shopify merchant and you. This is typically the "Password" field for the merchant.

• message is a string of all key-value pairs that start with x_ prefix, sorted alphabetically, and concatenated without separators.

Assuming your HMAC key is "iU44RWxeik", the signing mechanisms would look like this:

A working example of HMAC-SHA256 signing is available in our Hosted Payment Simulator GitHub repository.

If your integration looks like it is working, you can now add your payment gateway to your Shopify Partners account before publishing it.