Merging Customer Accounts in Shopify: What Happens to Orders, Emails and Addresses

When you merge customer accounts in Shopify, two profiles become one. One profile survives, and the other's orders, draft orders, addresses, notes, tags, tax settings, timeline events and customer-specific discounts move onto it. Contact details don't combine the same way: the merged profile keeps one email, one phone, one name and one default address, and the rest is discarded. The customer isn't told, and you can't undo it.

That split between "everything combines" and "only one survives" is what catches merchants out. This guide goes through each part of a profile, explains how Shopify decides which profile stays, and covers what to tell the customer afterward. For the click-by-click merge steps, see how to merge duplicate customers in Shopify.

What happens when you merge two customer accounts in Shopify?

Shopify keeps one profile and folds the other into it. According to Shopify's help documentation, a merge combines orders, draft orders, addresses, email address, phone number, name, notes, tags, tax settings, timeline events, credit cards, customer accounts, gift cards and discounts.

"Combines" means two different things depending on the field. Lists, like orders or addresses, are added together. Single values, like the email or first name, can only hold one answer, so one profile's value wins and the other is dropped. Here is how each part behaves, drawn from the Help Center page and the fields Shopify's merge preview API reports:

Two rows deserve care. Store credit isn't in the list at all: a profile with a store credit account can't be merged. And while the Help Center lists credit cards and gift cards among merged data, it also lists a vaulted (saved) credit card as a merge blocker, and the API has a CUSTOMER_HAS_GIFT_CARDS error code. In practice, expect profiles with saved cards or store credit to be refused, and some with gift cards too.

What happens to orders when customer accounts are merged?

Every order from both profiles ends up on the one profile that survives. Nothing is lost, and the orders themselves aren't edited: the order numbers, line items and payment records stay as they were.

This is also the only way to move orders between customers. Shopify's help documentation says orders stay permanently linked to the account that placed them, and editing an order's contact email doesn't change that. So if a customer checked out once as a guest with a work email and once with a personal email, merging the two profiles is how both orders appear in one order history.

The kept profile's order history now shows both sets of orders. A customer who looked like two one-time buyers becomes one repeat customer, which is often the whole point of the cleanup.

Which customer profile does Shopify keep?

The profile that survives is decided by the email address you keep. In the admin, Shopify's help documentation describes three cases:

You choose the email in the Merged customer section by clicking Change contact information (on the web) or Edit (in the mobile app). That choice matters beyond the email itself, since it also decides which customer ID lives on.

Shopify's GraphQL Admin API documents the same logic in more detail. If you pass customerIdOfEmailToKeep in the customerMerge mutation's override fields, that customer is kept. If you don't and both profiles have an email, the account state decides first: a profile with an enabled customer account wins. After that, an invited account can win unless email marketing consent points the other way, and if nothing separates them, the second customer ID passed in is kept. Developers can call the customerMergePreview query and read resultingCustomerId before merging, and the mutation returns the same field afterward.

Other single values can be chosen separately. The API's override fields cover the first name, last name, phone number and default address one by one, plus the final note and tag list. So you can keep one profile's email and another profile's phone.

What happens to the customer's email and sign-in?

The merged profile has one email, so the customer signs in with that email from then on. The discarded email isn't attached to any profile anymore.

This is where a merge can quietly undo itself. With new customer accounts, customers sign in without a password, using a one-time 6-digit code sent to their email (or with Shop, Google or Facebook where you've turned those on). Shopify's customer accounts documentation says the email on the profile identifies the account, and that signing in with an email that doesn't match any profile creates a new one. If your customer keeps typing the old address, they get a fresh, empty profile and a new duplicate.

Three things help:

• Keep the email they actually use. If one address is an old work email, keep the personal one, even if the work profile has more orders. The orders move either way.
• Tell them. Shopify doesn't notify the customer about a merge. A short note saying "your orders are now under jane@example.com" prevents the confusion.
• Don't change emails to merge. Shopify's documentation is explicit that editing an account's email doesn't merge profiles, and customers can't combine accounts themselves.

What happens to addresses, tags, notes and consent?

These combine, with a few limits worth knowing before you start.

Addresses. Both profiles' addresses end up in one list, and one default address is kept. Check which default is kept in the Merged customer section; you can pick the other profile's default before confirming.

Tags and notes. Tags are combined, and so are notes. The merge fails if the combined tags exceed 250 or the combined note exceeds 5,000 characters including spaces. The API's preview flags exactly these two as "blocking fields." If you're folding three or four profiles into one, the totals grow with each merge, so tidy tags and notes before the last one.

Marketing consent. If the customer is subscribed to email or SMS marketing on one profile but not the other, the merged profile is subscribed. Shopify's page mentions email and SMS only. That's convenient if the opt-in was real, but if one profile had explicitly unsubscribed, review the result rather than assuming the newer choice wins.

Timeline. Timeline events from both profiles land on the kept profile, so staff comments and history stay visible.

What doesn't change, and what to check outside Shopify?

The merge only changes Shopify's customer records. A few things sit around it:

• Nothing is sent. No email or SMS goes to the customer.
• There's no undo. Shopify states that a merge can't be reversed. Export your customers first if you want a record of both profiles as they were.
• Some profiles can't merge at all. Shopify refuses if either profile has or ever had a subscription contract, is linked to a B2B company or past B2B orders, has a vaulted card, has a store credit account, signs in through Multipass, was deleted or redacted, or is part of another merge or a customer data request in progress.
• Apps keep their own records. Email, loyalty, reviews and helpdesk apps often store their own copy of a customer, keyed to an email or a Shopify customer ID. How each one reacts to a merge depends on the app, so check its own documentation, especially for anything with a balance, like loyalty points.

A short pre-merge checklist covers most of this:

1. Confirm the two profiles are really one person (same email after normalizing, same phone, or same name and address).
2. Decide which email the customer will sign in with.
3. Check the default address, phone and name in Merged customer.
4. Count tags and note length if either profile is heavily tagged.
5. Note any loyalty or subscription data held in apps.
6. Merge, then tell the customer which email to use.

If you aren't sure which profiles are duplicates in the first place, start with how to find duplicate customers in Shopify.

How Twinfold helps

Twinfold is a Shopify app by NewClick (independent, not made by Shopify) that finds duplicate profiles and merges them in bulk through Shopify's own customer merge, so every rule in this guide applies the same way.

On each group you pick the profile to Keep as main profile and choose which name, phone and default address to keep, and After merging shows the result. Following Shopify's rule, the merged profile keeps the main profile's email and the other email is removed. Every merge is previewed with Shopify before you tick I understand that merged customers can't be unmerged and click Merge N customers. When Shopify refuses a merge, for example for store credit or a subscription history, Twinfold shows the reason and leaves those profiles unchanged, and Merge history with Download CSV gives you a record of what was merged.

Whichever way you merge, the decision that matters most is the email you keep. Get that right and tell the customer, and the rest of the account comes along with it.