In Shopify, if you want to use Postman to create a Discount, firstly you need to create a Price rule. The price rule will allow you to know what value of the discount, when and how you can apply it to customers.

Price rules have 2 ingredients: Entitlements and prerequisites. You can understand as follows:

• Entitlements are the precise resources to which a discount applies, such as goods, variations, or collections. 
• Prerequisites are the conditions that must be satisfied in order for the discount to apply to the resources that are eligible.

Example: Free Shipping for all customers buying over $50.

Now, I will show you how to create a price rule that gives the buyer $10 for an order. 

Step 1: Generate API credentials from the Shopify admin

• Log in to your Shopify admin
• Go to Apps – Manage private apps

• Click Create a new private app
• In the App details section, enter a name for your app, and an emergency developer email
• In the Admin API section, select the areas of your store that you want the app to access

• Click Save

The Admin API section displays the app’s API key and password when you save the app’s details.

Step 2: Create A Price Rule Using Postman In Shopify

• Log in to your Postman and create a new workspace
• Create a new POST with this URL:

https://{username}:{password}@{shop}.myshopify.com/admin/api/{api-version}/{resource}.json
Code language: JavaScript (javascript)

1. {username} – The API key that you generated.
2. {password} – The API password that you generated.
3. {shop} – The name of your development store.
4. {api-version} – The supported API version that you want to use.
5. {resource} – A resource endpoint from the REST Admin API.

Or you can copy this example in the Shopify Admin, remember change {resource} to {price_rules}:

https://33a72f01e02987636e1c1a9a4e95c840:[email protected]/admin/api/2021-10/price_rules.json
Code language: JavaScript (javascript)

• Paste the URL above.

In the body section, enter this code, then click Send.

{
    "price_rule": {
        "title": "SUMMERSALE10OFF",
        "target_type": "line_item",
        "target_selection": "all",
        "allocation_method": "across",
        "value_type": "fixed_amount",
        "value": "-10.0",
        "customer_selection": "all",
        "starts_at": "2021-12-10T13:00:10Z"
    }
}
Code language: JSON / JSON with Comments (json)

Explain of parameters in the payload: 

1. {Target_type} – There are 2 types: line_item and shipping_line
2. {Target_selection} – There are 2 selections: all and entitled
3. {allocation_method} – There are 2 methods (Each method: The discount is applied to each of the entitled items. Cross method: The calculated discount amount will be applied across the entitled items)
4. {value_type} – It can be a percentage, a fixed amount, or free shipping
5. {value} – The number of the discount value
6. {customer_selection} –  There are 2 selections: All and Prerequisite
7. {starts_at} – The date and time when the price rule was created.

Response:

The API will return all information about the created price rule.

I have shown you all steps to create a price rule with Shopify API using Postman. If you have any questions please leave a comment below or refer to our Devdocs. 

If you still do not understand the tutorial’s content, you can watch the video below for a more overview.

Hopefully, you can do it!