Shopify Migration Checklist: What Breaks Your Shipping Setup and How to Avoid It

Shipping is one of the most fragile parts of any ecommerce store, and it’s usually the part that gets the least attention during a platform migration. Teams spend weeks mapping products, rebuilding themes, and testing checkout, then treat shipping as a configuration step they can handle in an afternoon. That assumption is where most post-migration problems start.

When shipping breaks after a Shopify migration, it rarely fails loudly. Instead, it fails quietly. A rate calculates incorrectly for one region. A carrier stops receiving tracking updates. A product that should ship in a box marked “fragile” gets bundled into a flat rate that doesn’t account for its weight. None of these show up in a QA checklist unless someone is specifically looking for them, and by the time a customer complains, the damage to trust and margin has already happened.

This checklist walks through the shipping-specific failure points that show up most often during a migration to Shopify, along with what to check before you flip the switch. It’s drawn from patterns we’ve seen repeatedly across client migrations at Presta, where shipping is treated as its own workstream rather than an afterthought.

Why Shipping Breaks During a Migration

Shipping configuration is rarely a single setting. It’s a combination of product data, carrier integrations, tax rules, zone logic, and fulfillment workflows, all built on top of each other over time. On the old platform, these pieces often evolved organically, patched by whoever needed a fix at the time. A migration forces you to rebuild that logic from scratch, and any assumption that doesn’t get explicitly re-created gets silently dropped.

The result is a system that looks complete in a staging environment but starts producing wrong numbers the moment real order volume and real edge cases hit it.

The Core Areas That Break

Product weight and dimensions

Shopify’s shipping rates depend heavily on accurate weight and dimension data at the product and variant level. If this data was stored inconsistently on the old platform, or calculated dynamically through a plugin that doesn’t have a Shopify equivalent, migrated products often end up with default or missing values. That single gap can silently distort rates across an entire catalog, especially for stores with heavy or oversized items.

Carrier-calculated rates

Many stores rely on live rates from carriers like UPS, FedEx, or DHL rather than flat or tiered pricing. These integrations are tied to account credentials, service levels, and sometimes custom negotiated rates that don’t transfer automatically. It’s common to migrate the storefront successfully while the carrier connection quietly reverts to a generic rate table, which can either overcharge customers or eat into margin without anyone noticing for weeks. This is one of the reasons a structured migration sprint approach treats carrier reconnection as a dedicated checkpoint rather than a single line item.

Shipping zones and regional rules

Zone logic tends to accumulate complexity over the life of a store: exceptions for certain postal codes, restrictions on international orders, different rules for oversized freight versus small parcel. When this logic is rebuilt manually in Shopify, it’s easy to recreate the obvious rules and miss the exceptions, particularly ones that were only documented in a support agent’s memory rather than in the platform itself.

Tax and duty calculation on shipping

Depending on the client’s markets, shipping charges themselves may be taxable, and international orders may need duty and import tax calculated at checkout. These rules vary by jurisdiction and are easy to overlook when the team’s attention is on getting products and pricing right first.

Fulfillment and inventory sync

If the store uses a third-party fulfillment provider or a warehouse management system, that integration needs to be reconnected and tested with real order flows, not just a single test order. Sync issues often only appear at volume, when multiple orders hit the same SKU close together or when a partial shipment needs to be split correctly. Teams running a dedicated WooCommerce to Shopify migration process tend to catch this earlier, since fulfillment testing is scoped as its own phase rather than folded into general QA.

Tracking and post-purchase communication

Order status emails, tracking number sync, and delivery notifications are often handled by apps rather than Shopify’s native settings. These need to be reinstalled, reconfigured, and tested end to end, because a broken tracking sync doesn’t just look bad, it generates a spike in support tickets right after launch when volume and visibility are highest.

A Practical Pre-Launch Checklist

Before going live on Shopify, it’s worth working through this list specifically for shipping, separate from general QA:

• Audit product weight and dimensions across the full catalog, not just bestsellers
• Confirm carrier accounts are reconnected with the correct negotiated rates, not defaults
• Rebuild zone and regional rules from documented logic, not assumption
• Test tax and duty calculation on shipping charges for every relevant market
• Reconnect fulfillment and inventory integrations, then run a batch of test orders through the full cycle
• Verify tracking numbers sync correctly and trigger the right customer notifications
• Place real test orders from different regions, using different shipping methods, and check the final charged amount against expected pricing
• Compare a sample of before-and-after rates for the same cart contents to catch systemic pricing drift

Testing at Realistic Volume

A single successful test order proves the happy path works. It does not prove the system holds up under real conditions. Before launch, it’s worth simulating a batch of orders that mirrors actual order patterns: mixed cart sizes, international addresses, split shipments, and at least a few edge cases like oversized items or restricted postal codes. This is where sync issues and rate miscalculations tend to surface, and it’s far cheaper to catch them in a test environment than in front of paying customers.

Watching the First Weeks After Launch

Even a careful migration benefits from close monitoring in the first few weeks. Set up alerts for shipping rate anomalies, keep a close eye on support tickets tagged with shipping or delivery issues, and reconcile a sample of orders against expected shipping cost weekly rather than monthly. Problems caught in week one are a quick fix. Problems caught in month three, after they’ve quietly eaten into margin on hundreds of orders, are a much harder conversation.

Final Thought

Shipping doesn’t get the same spotlight as design or checkout during a migration, but it has an outsized effect on both customer trust and margin when it goes wrong. Treating it as its own workstream, with its own checklist and its own testing phase, is what separates a migration that goes smoothly from one that generates a wave of support tickets and quiet losses nobody notices until the numbers stop adding up.