---
title: "Send Invoice"
method: POST
path: "/v5/invoices/{invoice_id}/send"
tags: ["Invoicing"]
---

# Send Invoice

`POST /v5/invoices/{invoice_id}/send`

## Request

- Base URL: `https://sandbox.nmi.com/api`
- URL: `https://sandbox.nmi.com/api/v5/invoices/{invoice_id}/send`
- Auth: API key in header `Authorization`

Send an existing invoice to a customer via email.

## Path parameters

- `invoice_id` integer, required

## Response `200`

Success

- InvoiceResponse: Invoice response matching InvoiceRestSerializer structure
  - `object` 'invoice', required: Resource type identifier
  - `id` integer, required: Invoice ID
  - `status` 'open' | 'partially_paid' | 'paid' | 'closed' | 'overdue': Current status of the invoice
  - `amount` string: Total amount of the invoice. Format: `x.xx`
  - `subtotal` number, nullable: Subtotal amount before tax and shipping
  - `payment_terms` string: Payment terms for the invoice (e.g., 'Due Upon Receipt', '30 days')
  - `payment_methods_allowed` string[]: Allowed payment methods: 'cc' = Credit Card, 'ck' = Check, 'cs' = Cash
  - `processor_id` string, nullable: Processor ID for payment processing
  - `currency` string: Currency code (ISO 4217, e.g., USD, EUR)
  - `created_date` string, date-time, nullable: Date and time when the invoice was created in UTC ISO 8601 format
  - `updated_date` string, date-time, nullable: Date and time when the invoice was last updated in UTC ISO 8601 format
  - `billing_address` object: Billing address information
    - `first_name` string: First name
    - `last_name` string: Last name
    - `company` string: Company name
    - `email` string, email: Email address
    - `phone` string: Phone number
    - `fax` string: Fax number
    - `website` string: Website
    - `address1` string: Address line 1
    - `address2` string: Address line 2
    - `city` string: City
    - `state` string: State or province
    - `zip` string: ZIP or postal code
    - `country` string: Country code (ISO 3166-1 alpha-2)
  - `shipping_address` object: Shipping address information
    - `first_name` string: First name
    - `last_name` string: Last name
    - `company` string: Company name
    - `email` string, email: Email address
    - `address1` string: Address line 1
    - `address2` string: Address line 2
    - `city` string: City
    - `state` string: State or province
    - `zip` string: ZIP or postal code
    - `country` string: Country code (ISO 3166-1 alpha-2)
  - `order_details` object: Order details
    - `order_id` string: Order ID
    - `ip_address` string: IP address
    - `order_description` string: Order description
    - `po_number` string: Purchase order number
    - `customer_id` string: Customer ID
    - `customer_tax_id` string: Customer tax ID
    - `tax` string: Tax amount. Format: `x.xx`
    - `shipping` string: Shipping amount. Format: `x.xx`
    - `discount_amount` string: Discount amount. Format: `x.xx`
    - `surcharge` string: Surcharge amount. Format: `x.xx`
    - `tip` string: Tip amount. Format: `x.xx`
    - `shipping_carrier` string: Shipping carrier
    - `tracking_number` string: Tracking number
    - `shipping_date` string, date-time, nullable: Shipping date in UTC ISO 8601 format
  - `merchant_defined_fields` MerchantDefinedFields: Custom fields configured in the merchant control panel under Settings → Merchant Defined Fields (`field_1` through `field_20`).
    - `field_1` string: Merchant defined field 1
    - `field_2` string: Merchant defined field 2
    - `field_3` string: Merchant defined field 3
    - `field_4` string: Merchant defined field 4
    - `field_5` string: Merchant defined field 5
    - `field_6` string: Merchant defined field 6
    - `field_7` string: Merchant defined field 7
    - `field_8` string: Merchant defined field 8
    - `field_9` string: Merchant defined field 9
    - `field_10` string: Merchant defined field 10
    - `field_11` string: Merchant defined field 11
    - `field_12` string: Merchant defined field 12
    - `field_13` string: Merchant defined field 13
    - `field_14` string: Merchant defined field 14
    - `field_15` string: Merchant defined field 15
    - `field_16` string: Merchant defined field 16
    - `field_17` string: Merchant defined field 17
    - `field_18` string: Merchant defined field 18
    - `field_19` string: Merchant defined field 19
    - `field_20` string: Merchant defined field 20

## Other responses

- `400`: Bad Request - Validation Error
- `401`: Unauthorized
- `404`: Invoice not found

---

[API](https://skmtc.dev/nmi/apis/payments-api.md) - [All operations](https://skmtc.dev/nmi/apis/payments-api/llms.txt) - [OpenAPI document](https://skmtc.dev/nmi/apis/payments-api/revisions/c03727f27e27?raw)