diff --git a/event/event.go b/event/event.go
index 35bf269..4165b59 100644
--- a/event/event.go
+++ b/event/event.go
@@ -64,9 +64,15 @@ const (
 	// InvoiceIssued is emitted when an order is invoiced (pay-later placement or
 	// manual invoice issuance). Payload is an order.InvoiceIssued (platform/order).
 	InvoiceIssued Type = "invoice.issued"
-	// InvoicePaid is emitted when an invoiced order payment status crosses to paid.
-	// Payload is an order.InvoicePaid (platform/order).
+	// InvoicePaid is emitted for EVERY registered payment on an invoiced order
+	// (each event = one payment fact with its own amount/paidAt; the ledger
+	// books 1930→1510 per event). Payload is an order.InvoicePaid (platform/order).
 	InvoicePaid Type = "invoice.paid"
+	// InvoiceCredited is emitted when a credit note is issued against an issued
+	// invoice. Payload is an order.InvoiceCredited (platform/order): the credited
+	// amount + per-rate VAT split, which the ledger books as the reversal
+	// voucher (1510 C / 304x D / 261x D per rate).
+	InvoiceCredited Type = "invoice.credited"
 
 
 	// Analytics (tracking). Replaces the integer enum 0–6 that finder and
diff --git a/order/order.go b/order/order.go
index d171e76..1d93de7 100644
--- a/order/order.go
+++ b/order/order.go
@@ -59,16 +59,28 @@ func Decode(raw []byte) (Created, error) {
 	return c, err
 }
 
+// VatBucket is one VAT rate's split on an issued invoice: the net basis and
+// the VAT amount, both in minor units. RateBp is basis points (2500 = 25 %).
+// Summing ExVat+Vat across buckets equals AmountIncVat — the ledger reactor
+// books the invoice from these (revenue accounts per rate, e.g. 3041/3042/3043
+// and 2611/2621/2631 in BAS), so it needs the split, not just the total.
+type VatBucket struct {
+	RateBp int   `json:"rate_bp"`
+	ExVat  int64 `json:"ex_vat"`
+	Vat    int64 `json:"vat"`
+}
+
 // InvoiceIssued is the payload of an event.InvoiceIssued envelope.
 type InvoiceIssued struct {
-	OrderID       string `json:"order_id"`
-	InvoiceNumber string `json:"invoice_number"`
-	CompanyID     string `json:"company_id,omitempty"`
-	CustomerEmail string `json:"customer_email,omitempty"`
-	AmountIncVat  int64  `json:"amount_inc_vat"`
-	DueDate       string `json:"due_date"`
-	OCRReference  string `json:"ocr_reference"`
-	IssuedAtMs    int64  `json:"issued_at_ms"`
+	OrderID       string      `json:"order_id"`
+	InvoiceNumber string      `json:"invoice_number"`
+	CompanyID     string      `json:"company_id,omitempty"`
+	CustomerEmail string      `json:"customer_email,omitempty"`
+	AmountIncVat  int64       `json:"amount_inc_vat"`
+	VatBuckets    []VatBucket `json:"vat_buckets,omitempty"`
+	DueDate       string      `json:"due_date"`
+	OCRReference  string      `json:"ocr_reference"`
+	IssuedAtMs    int64       `json:"issued_at_ms"`
 }
 
 func (i InvoiceIssued) Encode() ([]byte, error) { return json.Marshal(i) }
@@ -86,6 +98,10 @@ type InvoicePaid struct {
 	CompanyID     string `json:"company_id,omitempty"`
 	AmountPaid    int64  `json:"amount_paid"`
 	PaidAtMs      int64  `json:"paid_at_ms"`
+	// OcrReference lets the ledger settle the exact receivable (the payment's
+	// 1510 credit references the invoice's OCR) without depending on the
+	// invoice.issued event having been booked first.
+	OcrReference string `json:"ocr_reference,omitempty"`
 }
 
 func (i InvoicePaid) Encode() ([]byte, error) { return json.Marshal(i) }
@@ -96,3 +112,28 @@ func DecodeInvoicePaid(raw []byte) (InvoicePaid, error) {
 	return i, err
 }
 
+// InvoiceCredited is the payload of an event.InvoiceCredited envelope: a
+// credit note was issued against an issued invoice. The credited amount and
+// per-rate VAT split mirror the credited lines (line total × qty / line
+// quantity, VAT proportionally — the same math as the order grain's
+// InvoiceCreditedAmount). The ledger books the reversal voucher
+// (1510 C / 304x D / 261x D per rate), idempotent per credit number.
+type InvoiceCredited struct {
+	OrderID       string      `json:"order_id"`
+	InvoiceNumber string      `json:"invoice_number"`   // the original invoice
+	CreditNumber  string      `json:"credit_number"`    // from the same gap-free series
+	CompanyID     string      `json:"company_id,omitempty"`
+	OcrReference  string      `json:"ocr_reference,omitempty"`
+	AmountIncVat  int64       `json:"amount_inc_vat"`
+	VatBuckets    []VatBucket `json:"vat_buckets,omitempty"`
+	CreditedAtMs  int64       `json:"credited_at_ms"`
+}
+
+func (c InvoiceCredited) Encode() ([]byte, error) { return json.Marshal(c) }
+
+func DecodeInvoiceCredited(raw []byte) (InvoiceCredited, error) {
+	var c InvoiceCredited
+	err := json.Unmarshal(raw, &c)
+	return c, err
+}
+