Invoice slips flowing from separate trays into a central binder ring, with a rubber stamp, a magnifier and a coin scale.

Invoicing is where a marketplace's clean split-order model meets the unglamorous reality of accounting. A single checkout can produce several invoices flowing in different directions — to the customer, from vendors, and between the platform and its vendors — and every one of them has to reconcile. Get the document flow right and month-end is boring; get it wrong and your accountant spends the first week of every month reconstructing what happened. Here is the invoice map, the reports that summarise it, and the audit trail that proves it.

Who invoices whom

The first source of confusion is that "the invoice" is not one document. On a marketplace there are typically three flows, and they answer different questions.

InvoiceFromToCovers
Customer invoiceThe seller of recordThe customerGoods plus shipping, with VAT, per vendor sub-order
Commission invoiceThe platformThe vendorThe platform's fee for the sale, as a taxable service
Settlement / payout statementThe platformThe vendorAmount owed: sales minus commission minus refunds

Exactly who is named on the customer invoice depends on who the seller of record is — the vendor or the platform — which is the same decision that drives your VAT position, covered in VAT for online marketplaces. What matters structurally is that the customer's single payment must reconcile with one customer-facing document set, while each vendor sees its own sales, its commission and its payout.

Per-vendor invoices from a single checkout

Because we split every basket into per-vendor sub-orders, each sub-order is the natural unit an invoice attaches to. A basket spanning three vendors produces three customer-facing invoice lines with three VAT breakdowns, all tied back to one payment reference on the parent order. This is not bureaucratic overhead — it is what makes a later refund, a VAT return or a vendor query answerable in seconds. When a customer asks "what did I actually pay vendor B?", the sub-order and its invoice already hold the exact answer, shipping VAT and all.

The alternative — one flat invoice for a mixed basket — looks simpler until the first exception. A partial refund, a per-vendor VAT question or a vendor disputing what it was credited all require you to un-blend a document that was never meant to come apart, and you end up doing at claim time the work you skipped at checkout. Splitting the invoice with the order pays that cost once, when the data is freshest.

Invoice registers and sequential numbering

Accountants and tax authorities expect invoices to be enumerable: a complete, gap-free register you can produce for any period. That means every invoice needs a stable identifier, a date, the parties, the net, the VAT and the gross, and it must be findable in a list rather than reconstructed from orders. Keep credit notes for refunds in the same register, linked to the invoice they reverse, so a partial refund is a traceable document and not a mysterious negative number. A register that is complete and ordered turns an audit from an ordeal into a query.

Two properties matter more than the exact numbering scheme. It should be immutable once issued — you correct an invoice with a credit note and a new invoice, never by editing the original, because a document that can be silently changed is worthless as evidence. And it should be complete: no missing sequence entries, because a gap is precisely what an auditor asks about first. Decide early whether the customer invoice numbering is per-vendor or platform-wide, keep it consistent, and never reuse a number.

The monthly report that keeps the accountant happy

The single artefact that makes bookkeeping calm is a monthly report that already contains what the accountant would otherwise assemble by hand.

From production

Our monthly bookkeeping report pulls together orders, VAT, refunds, the invoice register and per-vendor totals into one document, and reconciles it against the payment provider's status. Because the underlying orders are modelled correctly — VAT per sub-order, shipping VAT included, refunds reversing the tax they refunded — the report is a summary of true records rather than an estimate. Handing an accountant a reconciled monthly report instead of a raw order export is the difference between a review and an investigation.

The report's job is to answer the recurring questions before they are asked: how much VAT is due, what was refunded, how much each vendor is owed, and whether every payment the provider processed is accounted for in your books. Reconciliation against the provider is what closes the loop — see marketplace payments for the sweep that keeps order state and provider state in agreement.

Generate the report on a schedule and store each period as an immutable artefact, so last month's figures never quietly change when this month's data lands. That gives you a stable trail: the report your accountant reviewed is exactly the one that will still be there at year-end and, if it ever comes to it, at audit. A regenerated-on-demand number that shifts every time you open it is worse than no report at all.

Audit trails: who changed what

The last piece is provenance. On a marketplace, several parties can touch an order — an operator, a vendor working its own shop, an automated process issuing a refund — and when a number looks wrong months later, you need to know how it got that way. We audit every mutation: a role-scoped admin means a vendor can only act on its own orders, an operator has a broader view, and each change is recorded. An audit trail is not about distrust; it is what lets you answer "why is this figure what it is?" without guessing, and what lets you safely give vendors self-service access to their own data. For the offboarding case — when a vendor leaves and its data has to be handled correctly — see vendor offboarding.

Key takeaways

  • Treat invoicing as three flows, not one: the customer invoice, the platform's commission invoice to the vendor, and the settlement statement.
  • Attach invoices to per-vendor sub-orders so one payment reconciles to several VAT-correct documents and any query is answerable in seconds.
  • Keep a complete, gap-free invoice register with credit notes linked to the invoices they reverse, so an audit is a query, not an ordeal.
  • Produce a monthly report of orders, VAT, refunds, the register and per-vendor totals, reconciled against the payment provider.
  • Audit every mutation with role-scoped access, so you can always answer who changed a figure and why, and safely give vendors self-service.
  • Let the seller-of-record decision drive naming; confirm the invoicing and VAT structure with an accountant.

Frequently asked questions

Who issues the invoice on a marketplace?
The seller of record issues the customer invoice — either the vendor or the platform, depending on your model. Separately, the platform invoices each vendor for its commission as a taxable service, and provides a settlement statement of sales minus commission minus refunds. Which name is on the customer invoice follows your seller-of-record decision.
How does invoicing work when one order has several vendors?
The basket is split into per-vendor sub-orders, and each sub-order carries its own invoice with its own VAT breakdown, all tied to the single payment reference on the parent order. So a three-vendor basket produces three customer-facing invoice lines that reconcile back to one payment.
What should a monthly marketplace bookkeeping report contain?
At minimum: orders, VAT, refunds, an invoice register and per-vendor totals, reconciled against the payment provider's status. Because it summarises correctly modelled orders rather than re-deriving them, it lets an accountant review real records instead of reconstructing the month from a raw export.
Why keep an audit trail of order changes?
Because multiple parties — operators, vendors and automated processes — can touch an order, and when a figure looks wrong later you need to know how it got there. Auditing every mutation, with role-scoped access so vendors only touch their own orders, lets you answer why a number is what it is without guessing.

Month-end that's a review, not an investigation.

We produce per-vendor invoices and reconciled monthly reports on a marketplace that lives on your domain.

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