Combine a customer's orders into one monthly Xero invoice

Some businesses need one monthly invoice per customer or partner in Xero, summarising multiple Shopify orders (for example trade partners, B2B customers, or agents). Post to Xero cannot automatically generate one monthly invoice per contact, but you can achieve this with a simple workflow using draft invoices and Xero’s Copy & Merge feature.

At a high level:

Post to Xero creates one draft invoice per order in Xero, mapped to the correct contact.
At month end, you use Xero’s Copy & Merge to combine those draft invoices into a single invoice per contact.

When to use this workflow

This workflow is useful when:

You receive multiple Shopify orders from the same customer or partner during the month.
You want to send one consolidated invoice in Xero for that period.
You are happy to review and approve invoices manually before sending.

Common examples include:

Trade or wholesale partners billed monthly.
Referral or commission partners where you apply a manual commission or adjustment line on the invoice.
“On account” customers, where Shopify orders remain Payment Pending and the final billing is managed in Xero.

Step 1 – Configure Post to Xero to create draft invoices

First, configure Post to Xero so that every relevant Shopify order creates a draft invoice in Xero under the correct contact.

Key configuration points:

Use payment method, order status, and tags to filter which orders Post to Xero syncs (for example, a specific manual payment method, Payment Pending, and a particular tag).
Map Shopify customers to the corresponding Xero contacts so invoices land under the right customer.
Set the invoice status in Post to Xero to create draft invoices in Xero, not approved invoices, so they can be merged later.

Result: for each qualifying order, Post to Xero creates a draft invoice in Xero tied to the correct contact.

Step 2 – Ensure each draft has the right detail

Whatever is present on the Shopify order is what Post to Xero can send to Xero. Decide what information you want visible per order when you later merge invoices, such as:

Shopify order number.
End customer name (if you’re selling on behalf of a partner).
Order total or specific line descriptions.

If important information only exists in notes or metafields, you can use Shopify Flow or similar automation to add a dedicated line item to the order at creation time, so that data reliably flows through to the Xero invoice via Post to Xero.

Step 3 – Merge per-order drafts into one monthly invoice in Xero

At the end of the month, use Xero’s Copy & Merge to consolidate the draft invoices generated by Post to Xero.

Typical process in Xero:

Go to your Draft invoices list.
Filter by contact to show all draft invoices for one customer/partner for the period.
Select all relevant draft invoices for that contact.
Use the Copy & Merge option to create a single consolidated invoice.
Optionally add any adjustments (for example, a commission deduction line such as “30% Commission”) before approving and sending the invoice.

This gives your customer one clean invoice while still preserving detailed per-order information in the original drafts.

How Post to Xero handles updates and duplicates

Post to Xero is designed to avoid creating duplicate invoices when orders change.

If a Shopify order is edited and re-synced, Post to Xero updates the existing Xero invoice instead of creating a new one.
You can enable automatic updates so draft invoices remain in sync with order changes up until you perform your month-end merge.
Post to Xero does not write back to Shopify (for example, it cannot automatically tag orders as synced), but you can always see sync status in the Post to Xero dashboard and directly in Xero via the presence of draft invoices.