> ## Documentation Index > Fetch the complete documentation index at: https://docs.dolfinai.co/llms.txt > Use this file to discover all available pages before exploring further. # Send invoice > Mark an invoice as sent and deliver it to the customer. The optional request body lets the caller override individual fields of the email (Subject, PreviewText, GreetingLine, or OpeningBody Markdown) per send; any field omitted is resolved from the catalogue using the organisation's DefaultInvoiceMessageTone and industry. Pass an empty body (or no body) to send the catalogue-resolved email as-is. ## OpenAPI ````yaml /api-reference/openapi.json post /invoices/{id}/send openapi: 3.1.1 info: title: Dolfin API description: >- Dolfin API for AR & AP. Authenticate using the `x-dolfin-api-key` header with the API key distributed to your organisation. version: v1 servers: - url: https://api.dolfinai.co description: Production security: - {} tags: - name: Webhooks - name: Users - name: TaxRates - name: Suppliers - name: Supplier Credit Notes - name: Bills - name: SpendCategories - name: Payables - name: RecurringInvoices - name: Receivables - name: Purchase Orders - name: Products - name: Payments - name: Invoices - name: Organisations - name: Members - name: MCP - name: Matching - name: Invoice Reminders - name: Industries - name: Gmail - name: Delivery Notes - name: Customers - name: Currencies - name: Credit Notes - name: Clients - name: ClientInvites - name: BankPayments - name: Bank details - name: Auth - name: ApprovalPolicies - name: ApiKeys - name: Agent paths: /invoices/{id}/send: post: tags: - Invoices summary: Send invoice description: >- Mark an invoice as sent and deliver it to the customer. The optional request body lets the caller override individual fields of the email (Subject, PreviewText, GreetingLine, or OpeningBody Markdown) per send; any field omitted is resolved from the catalogue using the organisation's DefaultInvoiceMessageTone and industry. Pass an empty body (or no body) to send the catalogue-resolved email as-is. parameters: - name: id in: path required: true schema: type: string format: uuid requestBody: content: application/json: schema: oneOf: - type: 'null' - $ref: '#/components/schemas/SendInvoiceOverrides' responses: '200': description: OK content: application/json: schema: $ref: '#/components/schemas/InvoiceResponse' '400': description: Invoice.CustomerMissingEmail — the customer has no email address content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' '403': description: >- Organisation.InsufficientRole — caller's organisation role is below the level this action requires content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' '404': description: >- Invoice.NotFound — no invoice with that id for this organisation Organisation.NotFound — the organisation does not exist or could not be resolved content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' '409': description: >- Invoice.CommandFailed — the invoice command was rejected by the saga (state conflict) Invoice.NotSendable — invoice is not in Draft status content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' '422': description: >- Invoice.RecipientInactive — the recipient address is suppressed at the email provider content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' '502': description: Invoice.EmailSendFailed — the email provider rejected the send content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' components: schemas: SendInvoiceOverrides: type: object properties: tone: oneOf: - type: 'null' - $ref: '#/components/schemas/InvoiceTone' description: >- Resolves the catalogue with this tone instead of the organisation's default for this send only. When null, the organisation's DefaultInvoiceMessageTone is used. subject: type: - 'null' - string description: >- Overrides the catalogue-resolved email Subject. When null, catalogue resolves. previewText: type: - 'null' - string description: >- Overrides the catalogue-resolved inbox preview text (the line that previews next to the subject in most clients). When null, catalogue resolves. greetingLine: type: - 'null' - string description: >- Overrides the catalogue-resolved greeting line (e.g. "Hi Acme,"). When null, catalogue resolves. openingBodyMarkdown: type: - 'null' - string description: >- Overrides the catalogue-resolved opening body. Markdown; rendered to HTML at send time. When null, catalogue resolves. reminders: type: - 'null' - array items: $ref: '#/components/schemas/InvoiceReminderOffset' description: >- Override the organisation's DefaultReminderOffsets for this send. null (or field omitted): use the organisation's default list. []: schedule no reminders for this send. Populated: schedule exactly these offsets, overriding the organisation default. Each offset is resolved relative to the invoice's DueDate; offsets that would resolve to a past time are skipped silently. InvoiceResponse: required: - currency type: object properties: id: type: string format: uuid organisationId: type: string format: uuid customerId: type: string format: uuid documentNumber: type: - 'null' - string currency: type: string description: ISO 4217 currency code (e.g. GBP, USD, EUR) issueDate: type: string format: date-time dueDate: type: - 'null' - string format: date-time status: $ref: '#/components/schemas/InvoiceState' subTotal: pattern: ^-?(?:0|[1-9]\d*)(?:\.\d+)?$ type: - number - string format: double taxAmount: pattern: ^-?(?:0|[1-9]\d*)(?:\.\d+)?$ type: - number - string format: double totalAmount: pattern: ^-?(?:0|[1-9]\d*)(?:\.\d+)?$ type: - number - string format: double amountPaid: pattern: ^-?(?:0|[1-9]\d*)(?:\.\d+)?$ type: - number - string description: Total payments received against this invoice. format: double amountCredited: pattern: ^-?(?:0|[1-9]\d*)(?:\.\d+)?$ type: - number - string description: Total of issued credit notes applied to this invoice. format: double outstanding: pattern: ^-?(?:0|[1-9]\d*)(?:\.\d+)?$ type: - number - string description: >- Remaining balance: TotalAmount - payments received - issued credit notes. format: double recurringScheduleId: type: - 'null' - string description: >- Set when this invoice was generated from a recurring schedule; null for hand-made invoices. format: uuid recurringOccurrenceNumber: pattern: ^-?(?:0|[1-9]\d*)$ type: - 'null' - integer - string format: int32 memo: type: - 'null' - string createdAt: type: string format: date-time createdBy: type: - 'null' - string format: uuid updatedAt: type: string format: date-time updatedBy: type: - 'null' - string format: uuid paymentUrl: type: - 'null' - string customer: oneOf: - type: 'null' - $ref: '#/components/schemas/CustomerResponse' lineItems: type: array items: $ref: '#/components/schemas/InvoiceLineItemResponse' ProblemDetails: type: object properties: type: type: - 'null' - string title: type: - 'null' - string status: pattern: ^-?(?:0|[1-9]\d*)$ type: - 'null' - integer - string format: int32 detail: type: - 'null' - string instance: type: - 'null' - string InvoiceTone: enum: - Friendly - Direct - Formal InvoiceReminderOffset: enum: - OneWeekBefore - TwoDaysBefore - OnDueDate - TwoDaysAfter - OneWeekAfter InvoiceState: enum: - Draft - Sent - Paid - Void - PartiallyPaid - Credited CustomerResponse: required: - name type: object properties: id: type: string format: uuid organisationId: type: string format: uuid name: type: string email: type: - 'null' - string phone: type: - 'null' - string taxNumber: type: - 'null' - string addressLine1: type: - 'null' - string addressLine2: type: - 'null' - string city: type: - 'null' - string state: type: - 'null' - string postalCode: type: - 'null' - string country: type: - 'null' - string description: ISO 3166-1 alpha-2 country code (e.g. GB, US, DE) createdAt: type: string format: date-time createdBy: type: - 'null' - string format: uuid updatedAt: type: string format: date-time updatedBy: type: - 'null' - string format: uuid InvoiceLineItemResponse: required: - description type: object properties: id: type: string format: uuid productId: type: string format: uuid productName: type: - 'null' - string taxRateId: type: - 'null' - string format: uuid taxRateSnapshot: oneOf: - type: 'null' - $ref: '#/components/schemas/TaxRateSnapshotResponse' description: >- Frozen copy of the tax rate as applied when the invoice was sent. Read-only — no tool can modify a sent invoice's tax. Present on Sent/Paid/Void invoices, null on Draft. description: type: string quantity: pattern: ^-?(?:0|[1-9]\d*)(?:\.\d+)?$ type: - number - string format: double unitPrice: pattern: ^-?(?:0|[1-9]\d*)(?:\.\d+)?$ type: - number - string format: double taxAmount: pattern: ^-?(?:0|[1-9]\d*)(?:\.\d+)?$ type: - number - string format: double subTotal: pattern: ^-?(?:0|[1-9]\d*)(?:\.\d+)?$ type: - number - string format: double TaxRateSnapshotResponse: required: - code - name - source type: object properties: code: type: string name: type: string rate: pattern: ^-?(?:0|[1-9]\d*)(?:\.\d+)?$ type: - number - string format: double source: type: string sourceId: type: - 'null' - string format: uuid snapshottedAt: type: string format: date-time ````