# How to run a Shopify affiliate program without editing your theme

> Start with affiliate discount codes and native paid-order webhooks. No theme.liquid change is needed until you want link attribution.

Published: 2026-07-20 · Last reviewed: 2026-07-20

## Discount codes first

The fastest way to launch a Shopify affiliate program is to skip storefront code entirely. Connect your store, approve an affiliate, then create a Shopify discount whose code exactly matches the referral code on that affiliate's Attribloom detail page. Hand the code to the affiliate. When a shopper uses it at checkout, Shopify includes it in the paid order and Attribloom matches it to the affiliate.

Attribloom calls this a validated discount code: a Shopify checkout code that exactly matches an affiliate referral code already recorded in Attribloom. There is no theme edit and no storefront script involved.

## How the sale is confirmed

Shopify emits HMAC-signed paid-order and refund webhooks from its own servers. Attribloom verifies the signature, reads the discount code, and credits the matching affiliate. Commission is calculated on the post-discount merchandise subtotal, excluding tax and shipping, and a refund reverses the matching share on a double-entry ledger.

- No storefront pixel: the order is confirmed from Shopify's server-side webhook.
- Commission basis: post-discount merchandise subtotal, excluding tax and shipping.
- Refunds, full or partial, reverse the matching commission automatically.

## The limit of discount-code attribution

Discount codes only credit an affiliate when the shopper actually enters the code. A visitor who arrives from an affiliate link but checks out without the code is not attributed. If you want to credit a visit without asking the shopper to type a code, you add link attribution, which reads a ?ref parameter and preserves it on the cart. That is the one case that warrants a small theme.liquid change.

Most programs start code-only and add link attribution later, once the affiliate channel is worth the storefront change. The two paths can run together, and Attribloom fails closed if a discount code and a ref value ever identify different affiliates.

## Frequently asked

### Do I have to edit my theme to run a Shopify affiliate program?

No. The discount-code path needs no theme or storefront change. A theme.liquid edit is only required if you later add link attribution that credits a visit without a discount code.

### What does the discount-code path miss?

It only credits a sale when the shopper enters the code. A shopper who came from an affiliate link but did not use the code is not attributed unless you add link attribution.

### How is the commission amount calculated?

On the post-discount merchandise subtotal in the store's currency, excluding tax and shipping. Refunds reverse the matching share.

## Primary sources

- [Shopify: app webhooks](https://shopify.dev/docs/apps/build/webhooks) · checked 2026-07-20
- [Shopify: manage discount codes](https://help.shopify.com/en/manual/discounts/managing-discount-codes) · checked 2026-07-20

## Next steps

- [Shopify affiliate software guide](/guides/shopify)
- [How to launch a Shopify affiliate program](/learn/launch-shopify-affiliate-program)