How to auto-apply promotion codes at checkout

What is auto-apply for promotion codes?

Auto-apply allows promotion codes to be automatically included in your partners' referral links. When a visitor clicks a referral link, the promotion code is passed to your website and can be automatically pre-filled in the coupon input field at checkout, creating a seamless discount experience for customers.

Requirements

To use auto-apply promotion codes, you need:

  1. An active integration (Stripe, Paddle Billing, Shopify, or WooCommerce) or a custom API setup
  2. At least one coupon with promotion codes assigned to partners
  3. The Partnero tracking script installed on your website

How to enable auto-apply promotion codes

Follow the two-step process to enable auto-apply promotion codes for your program.

Step 1: Enable "Include promotion codes in referral links"

  1. Go to Program → Settings in your Partnero dashboard.
  2. Scroll down to the Coupon tracking section.
  3. Enable the toggle Include promotion codes in referral links: 
  4. Click Update to save changes.

When enabled, this setting automatically appends the partner's promotion code to all their referral links. For example:

Note: This can also be configured individually for each partner on their profile page.

Step 2: Configure coupon input field IDs

Coupon input field IDs tell Partnero where to auto-fill the promotion code on your checkout page.

  1. In the Coupon tracking section, find the Coupon input field IDs.
  2. Click Add field ID: 
  3. Enter the HTML ID of your coupon input field (e.g., discount-code).
  4. Click Update.

You can add multiple field IDs if your website has different checkout pages with different coupon field names.

Important: Make sure the field ID exactly matches your checkout form (IDs are case-sensitive).

Auto-apply with Stripe

Stripe offers several ways to accept payments. How auto-apply works depends on which Stripe product you're using:

Stripe Payment Links 

Automatic coupon application is fully supported with Stripe Payment Links.

When a visitor clicks a partner's referral link that includes a promotion code (e.g., ?coupon=JOHN20), the coupon is automatically applied at the Stripe Payment Link checkout. No additional configuration is needed; it just works.

Custom checkout page

If you have a custom checkout page (not using Stripe's hosted solutions), configure the coupon input field ID as described in Step 2, and Partnero will auto-fill the code into your form.

How it works

  1. Partner shares their link: The partner's referral link includes their promotion code (e.g., ?coupon=JOHN20).
  2. The visitor clicks the link: When someone clicks the link, Partnero detects the promotion code.
  3. Code is saved: The promotion code is stored in a browser cookie, so it persists as the visitor browses your site.
  4. Auto-fill at checkout: When the visitor reaches your checkout page, Partnero automatically fills the promotion code into the coupon input field.
  5. Sale is tracked: After purchase, the transaction is attributed to the partner who owns that promotion code.

Example setup

Here's an example of a complete auto-apply configuration:

Your settings:

  • "Include promotion codes in referral links" is enabled
  • Coupon input field ID: promo-code

Partner John's referral link:

https://yoursite.com/pricing?via=john&coupon=JOHN20

Customer experience:

  1. Customer clicks John's referral link
  2. Customer browses your website
  3. Customer goes to checkout
  4. The code JOHN20 is automatically filled in the promo code field
  5. Customer sees their discount applied
  6. After the purchase, John receives credit for the sale

Troubleshooting

The coupon code is not auto-filling

  • Make sure the field ID exactly matches your checkout form (IDs are case-sensitive)
  • Verify the Partnero tracking script is installed on your checkout page
  • Check that the URL contains the coupon parameter (e.g., ?coupon=CODE)
  • Try enabling debug mode in your browser console to see Partnero messages

The coupon is not being tracked after purchase

  • Confirm the promotion code is assigned to a partner in Partnero
  • Check that your payment integration is connected and working
  • Verify the same coupon exists in both Partnero and your payment provider (Stripe, Paddle, etc.)

Partners don't see the coupon in their referral links

  • Make sure "Include promotion codes in referral links" is enabled
  • Verify the partner has at least one promotion code assigned to them
  • Check if automatic promotion codes are configured