Learn what the Courier Reference Code is in Zonal, when to enter or update it, and why each courier must have its own unique code for Shopify.

<h2 data-pm-slice="1 1 []" id="isPasted">What is a Courier Reference Code?</h2>When you create a courier in Zonal, you need to enter a Courier Reference Code.This code is the unique identifier Zonal passes to Shopify so Shopify knows which courier to offer to the customer at checkout.The code can come from a third-party provider, such as a courier company or an EPOS system, but it does not have to. You can also create your own code as long as each courier has a different one.<hr>INFOThe Courier Reference Code is used to identify the courier in Shopify. It should be unique for every courier you set up in Zonal.<hr><h2 id="when-you-need-to-enter-it">When you need to enter it</h2>1. Create a courier -&#xA0;In Zonal, go to the screen where you add a new courier and complete the courier details.2. Enter Courier Reference Code -&#xA0;In the Courier Reference Code field, enter the identifier you want Shopify to use for that courier.3. Save the courier -&#xA0;Save the courier once you have confirmed the code is unique and matches the courier you want Shopify to offer.<h2 id="when-you-may-be-asked-to-update-it">When you may be asked to update it</h2>If you edit a courier that already has a Courier Reference Code, Zonal may show a prompt asking you to update it if another courier is already using the same code.This prompt is there to help prevent duplicate courier identifiers.<hr>WARNINGIf two couriers share the same Courier Reference Code, Shopify may become confused about which courier to show and can offer the wrong courier in some situations.<hr><h2 id="best-practice-for-choosing-a-code">Best practice for choosing a code</h2><ul><li>Use a code that is unique to that courier only.</li><li>If you already have a reference from a courier company or EPOS system, you can use that.</li><li>If you do not have an existing reference, create your own naming pattern and keep it consistent.</li><li>Do not reuse the same code across multiple couriers, even if the courier names are similar.</li></ul><h2 id="why-unique-codes-matter">Why unique codes matter</h2>Shopify uses the Courier Reference Code to decide which courier option to offer to the customer.If more than one courier shares the same code, Shopify may not be able to reliably tell them apart. That can lead to the wrong courier being shown during checkout or in other delivery selection scenarios.<h2 id="if-you-see-a-duplicate-code-prompt">If you see a duplicate code prompt</h2><ol><li>Review the Courier Reference Code on the courier you are editing.</li><li>Check whether another courier in Zonal is already using that same code.</li><li>Update the code so it is unique.</li><li>Save your changes.</li></ol>If the code came from a third-party system, make sure the updated value still matches the identifier you expect Shopify to use.<h2 id="quick-checklist">Quick checklist</h2><ul><li>Every courier has a value in Courier Reference Code.</li><li>No two couriers use the same code.</li><li>The code matches your intended courier mapping in Shopify.</li><li>Any third-party reference you use is entered exactly as needed.</li></ul>

About courier reference codes

Understand how Blacklisted Postcodes and Whitelisted Postcodes work in Zonal, including wildcard matching, rule scope, and how to avoid unintended postcode matches.

<h2 data-pm-slice="1 3 []" id="isPasted">How postcode rules work in Zonal</h2>In Zonal, postcode rules are added at the Shipping Rate level, not on the courier itself. You add them when creating or editing a rate from Shipping Rates by opening the Add Shipping Rate popup.Use Blacklisted Postcodes to stop a rate from being offered in specific areas. Use Whitelisted Postcodes to make a rate available only in specific areas.<hr>INFOYou can enter postcodes as a full postcode or as a partial postcode with a wildcard.<hr><h2 id="where-to-add-postcode-rules">Where to add postcode rules</h2>1. Open Shipping Rates -&#xA0;In Zonal, go to Shipping Rates.2. Add or edit a rate -&#xA0;Click Add Shipping Rate, or open an existing rate you want to update.3. Open the rate popup -&#xA0;In the Shipping Rates section, use the rate popup where you set Min. Weight (g), Max. Weight (g), Min. Order Value, Max. Order Value, and Price.4. Enter postcode rules -&#xA0;Add your entries in Blacklisted Postcodes or Whitelisted Postcodes. Enter multiple values separated by commas.5. Save the rate -&#xA0;Click Add Rate to save the postcode rule as part of that shipping rate.<h2 id="supported-postcode-formats">Supported postcode formats</h2><h3 id="full-postcode">Full postcode</h3>Enter the whole postcode with no spaces.Example: <code>NE61AA</code>This matches that exact postcode only.<h3 id="partial-postcode-with-wildcard">Partial postcode with wildcard</h3>Add an asterisk at the end of the partial postcode to match any postcode that starts with that value.Example: <code>NE6*</code>This matches any postcode beginning with <code>NE6</code>.<hr>TIPIf you want a broad area match, use a wildcard. If you want a precise match, use the full postcode without spaces.<hr><h2 id="how-wildcard-matching-affects-scope">How wildcard matching affects scope</h2>Wildcard rules are prefix matches. This means Zonal checks whether the customer&apos;s postcode starts with the characters you entered before the <code>*</code>.For example, if you add <code>NE6*</code>, the rate can apply to postcodes such as:<ul><li><code>NE61AA</code></li><li><code>NE62BB</code></li><li><code>NE63CC</code></li></ul>Because those postcodes all begin with <code>NE6</code>, they are all treated as matches.<hr>WARNINGA wildcard can cover more postcodes than you expect. If a rate is appearing for a wider area than intended, the postcode pattern is usually too broad.<hr><h2 id="example-when-a-rule-is-too-broad">Example: when a rule is too broad</h2>If you want to allow postage to <code>NE1</code> but not to <code>NE61</code>, using <code>NE6*</code> will not work.That is because <code>NE6*</code> also matches longer postcodes that begin with <code>NE6</code>.In this situation, the rule needs to be more specific. For example:<ul><li><code>NE61A*</code></li></ul>A more specific wildcard narrows the match so the rate applies only to postcodes starting with that longer prefix.<h2 id="choosing-between-blacklist-and-whitelist">Choosing between blacklist and whitelist</h2><h3 id="use-whitelisted-postcodes-when">Use Whitelisted Postcodes when</h3><ul><li>the rate should be available only in defined areas</li><li>you are setting up a local, regional, or limited-delivery service</li><li>you want tighter control over where the rate appears</li></ul><h3 id="use-blacklisted-postcodes-when">Use Blacklisted Postcodes when</h3><ul><li>the rate should be available in most areas except a few exclusions</li><li>you need to block surcharge areas or unsupported destinations</li><li>you already have a broad rate and only need to remove certain postcode ranges</li></ul><hr>NOTEIf you add Whitelisted Postcodes, the rate becomes restricted to matching postcodes only. If you use Blacklisted Postcodes, matching postcodes are excluded from that rate.<hr><h2 id="best-practices-for-accurate-postcode-rules">Best practices for accurate postcode rules</h2><ul><li>Remove spaces from full postcode entries.</li><li>Use full postcodes when you want an exact match.</li><li>Use wildcards only when you are confident the broader prefix is correct.</li><li>Make wildcard rules as specific as possible if nearby postcode ranges must behave differently.</li><li>Review other conditions on the same rate, including weight, order value, and destination, so you understand the full scope of the rule.</li></ul><h2 id="troubleshooting-postcode-matches">Troubleshooting postcode matches</h2>Q. Why is my shipping rate showing for more postcodes than expected?A. The most common reason is a wildcard that is too broad. For example, <code>NE6*</code> matches every postcode that starts with <code>NE6</code>, including longer values such as <code>NE61</code>. Make the rule more specific if you only want a smaller range.<hr>Q. Why is my shipping rate not appearing for a postcode I expected to match?A. Check whether the postcode is entered in the correct field, whether the entry is too specific, and whether another rule on the same rate is preventing it from applying. Also review the selected Shipping Zone or Single Country, weight limits, and order value limits.<hr>Q. Should I use spaces in postcode entries?A. No. For postcode rules in the Add Shipping Rate popup, enter full postcodes without spaces, such as <code>NE61AA</code>.<hr>Q. Can I add multiple postcode rules to one rate?A. Yes. Enter multiple values separated by commas in Blacklisted Postcodes or Whitelisted Postcodes.

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About courier reference codes

Postcode rules in shipping rates