---
search:
  tags:
    - billing
    - POST
seo:
  description: >-
    Marks an invoice as sent to the customer. This changes the… Reference for
    the POST /billing/invoices/{id}/mark-as-sent endpoint in the Leadtime Public
    API API.
sidebar:
  badge: POST
  label: Mark invoice as sent
title: Mark invoice as sent
type: openapi-operation
---
Marks an invoice as sent to the customer. This changes the invoice status from "New" to "Sent", records the sending date, and calculates the payment due date based on organization or workspace payment terms.

**What happens when you mark an invoice as sent:**
1. Invoice status changes from "New" to "Sent"
2. Sending date (`sentAt`) is recorded as the current date
3. Sending type is set to "Manual" (indicating manual marking, not email sending)
4. Contact recipient is recorded (from invoice contactId)
5. Payment due date (`dueDate`) is calculated based on:
   - Organization-specific payment terms (`invoiceDueDays`), or
   - Workspace default payment terms (`defaultInvoiceDueDays`)
6. Status change timestamp and user are recorded
7. The payment term starts running from this point

**Important restrictions:**
- Only invoices with status "New" or "Sent" can be marked as sent
- Invoices that are "Paid" or "Cancelled" cannot be marked as sent
- This endpoint marks the invoice as sent manually (use send invoice endpoint for email sending)

**Use cases:**
- Record that an invoice was sent manually (e.g., via postal mail or other channels)
- Update invoice status after external sending
- Start payment term tracking

**What is returned:**
- Success response confirming the invoice was marked as sent

<Operation source="api-reference" id="invoicescontroller-markassent" />