Invoices
The billing documents — what you charge customers, and what suppliers charge you.
An invoice records money owed. Carbon has two kinds that behave almost identically: a sales invoice is what you bill a customer, and a purchase invoice is the bill a supplier sends you. Both are drawn from an upstream document, both post to the ledger, and both are settled by a separate posted transaction — a or a applied to the invoice, not a field you flip.
Where they come from
A sales invoice is raised from a , or from a : billing on the order or billing on what actually shipped. A purchase invoice is raised from a , keeping the lines that still have something to bill. Either way the new invoice opens at Draft, fully editable, and links each line back to the order line it bills.
A purchase invoice reconciles on the purchase order line, not on a . There's no direct receipt link, and a receipt isn't even required to bill. Posting clears the accrual against the shared order line and books any price difference to .
Status lifecycle
Both start at Draft and lock the moment they leave it — numbers that have entered the books can't be edited in place. The two sides share a shape but name a few states differently.
| Sales invoice | Purchase invoice | |
|---|---|---|
| Drafting | Draft, Pending | Draft, Pending |
| Posted | Submitted | Open |
| Paying | Partially Paid → Paid | Partially Paid → Paid |
| Reversed | Voided | Voided |
| Memo applied | Credit Note Issued | Debit Note Issued |
| Past due | Overdue | Overdue |
The posted state has a different name on each side, Submitted for sales and Open for purchase, but means the same thing: posted to the ledger, awaiting payment. Overdue, Partially Paid, and Paid aren't set by hand; they're computed from the invoice's settlements and due date. An unpaid invoice past its dateDue reads Overdue; once settlements cover the whole balance it reads Paid.
Line types
An invoice line is one of a handful of types, most of which pull an item's details in for you. The two sides differ in one place:
| Type | Sales invoice | Purchase invoice |
|---|---|---|
| Part, Service, Material, Tool, Consumable | Yes | Yes |
| Comment (a note, no charge) | Yes | Yes |
| Fixed Asset | Yes | — |
| G/L Account (charge straight to an account) | — | Yes |
A G/L Account line lets a purchase invoice book a cost directly to a ledger account with a description — freight, a fee, anything without an item behind it. Sales invoices don't offer it; they carry a Fixed Asset line instead, for billing a capitalized asset.
Posting
an invoice writes its general-ledger entries, but only when accounting is enabled for the company: receivables against sales for a sale, payables against inventory or WIP for a purchase. Posting also bumps the invoiced quantity on each order line and stamps the posting date.
Posting never marks an invoice Paid — it lands on Submitted or Open. Settling it is a separate, deliberate step. A posted invoice can't be deleted either; to undo one you void it, which writes reversing entries rather than erasing history.
Settling an invoice
A posted invoice is settled by a separate posted document applied to it, never by flipping a field. Two kinds of document do the settling, and an invoice settlement is the row that links one to an invoice for a given amount.
A moves cash. A Receipt is money in from a customer (it settles sales invoices); a Disbursement is money out to a supplier (it settles purchase invoices). A payment carries a bank account, a date, a currency, and a total, and moves Draft → Posted → Voided like the invoice itself. While it's Draft you stage which invoices it applies to and for how much; posting it books the cash to the ledger — bank against the receivables or payables control account — and freezes those applications.
A settles without cash. It's a party, an amount, and a reason: a Credit memo lowers what a customer owes (a return or allowance) or raises what you owe a supplier; a Debit memo does the reverse. Its offset is a general-ledger reason account, not the bank. A memo posts Draft → Posted → Voided too, and posting an applied credit against a customer invoice is what flips that invoice to Credit Note Issued (a supplier invoice reads Debit Note Issued). A memo belongs to exactly one party — a customer or a supplier, never both.
An invoice settlement carries three amounts, not one: applied (cash or credit that reduces the balance), discount (an early-payment discount you're granting), and write-off (a tiny remainder you're forgiving to the write-off account). At least one has to be positive. A memo-sourced settlement can only carry an applied amount — discounts and write-offs are for cash payments.
What if a payment overpays?
Applying more than an invoice's open balance is blocked per-invoice — a settlement can't exceed what's left to collect on that invoice. But a payment's cash total can exceed everything it applies: the excess stays on the party's account as an unapplied credit, ready to apply to a later invoice. You can also run the reverse — a payment with zero cash that only applies the party's existing posted credits to open invoices. Applying more credit than the party actually has, though, errors out.
Voiding and dust
Void reverses, it doesn't erase. Voiding a posted payment or memo writes a mirror-image journal and moves it to Voided. You can't void an invoice that still has payments applied — reverse (or unapply) those first. And you can't edit a payment's applications once it's posted; to change how a posted payment lands, void it and re-enter it.
Carbon forgives dust. When settlements leave a balance under one cent — smaller than the currency can represent — the invoice is treated as fully Paid and its balance reads zero, rather than sitting forever a fraction of a cent short.