Discount stacking: test the basket before sending the campaign

Write down the combined promise

Shopify's discount documentation says multiple discounts apply together only when each discount's combination settings allow it. That is a configuration rule with a customer-facing consequence. Imagine a hypothetical footwear shop running an automatic sale while emailing a welcome code. A new buyer may reasonably expect both if the email does not explain the relationship. Before sending a campaign, decide the intended outcome for that basket and confirm the settings produce it. Do not leave the interpretation to the customer who discovers a different total at checkout.

• Shopify: combining discounts ↗

Use a basket matrix

Prepare a short table of realistic purchases: a full-price pair, a discounted pair, a mix of both and a basket near any delivery threshold. Add the welcome code to each and record the expected total before running the test. Include a customer who qualifies for a separate loyalty offer if that exists. Keep the arithmetic simple enough for the campaign owner to verify. A screenshot showing that a code was accepted is weaker evidence than a line-by-line explanation of the amount the customer will actually pay.

Give support a consistent explanation

For each excluded combination, write one sentence that explains what the buyer can use instead. Keep it consistent across the email, promotion page and checkout messaging available in the selected setup. Staff should not have to invent a goodwill rule for every inquiry. If an exception is approved, record why and who authorised it. Avoid publishing a list of technical discount classes as customer instructions. Translate the rule into the products and offer names the shopper recognises, while retaining the detailed matrix internally for troubleshooting. Keep the expected basket totals beside the campaign approval, so a later support question can be checked against what the team intended.

Review the campaign after changes

Repeat the relevant basket tests whenever an overlapping promotion begins or ends, or when eligible products change. Assign someone to remove expired banners and ensure that shared links still describe the live offer accurately. For the footwear shop, the completion check is not merely that the campaign email was delivered. It is that a customer can reproduce the promised price and the team can explain an excluded basket. Use actual order results to assess the campaign later; combining discounts is not, by itself, evidence of improved profitability.