> ## Documentation Index
> Fetch the complete documentation index at: https://docs.flexprice.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Delegated Invoicing

> The subscription belongs to one customer, but the invoice is sent to a different customer: the delegated payer. Entitlements, usage, and line items stay on the subscription owner.

## Overview

Delegated invoicing lets you separate **who uses** a subscription from **who pays** for it. The subscription owner (child) keeps full ownership of their plan, line items, usage tracking, and entitlements. Every invoice is raised against a designated billing customer: the delegated payer.

`subscription_type` result: **`standalone`** (with `invoicing_customer_id` set on the subscription record)

<Note>
  Delegated invoicing does not create a new subscription type. The subscription owner's subscription is still `standalone`. What changes is the **invoicing customer ID** stored on the subscription, which redirects invoice generation and wallet drawdown to the delegated payer.
</Note>

## How it works

```mermaid theme={null}
flowchart LR
  A[Subscription owner usage] --> B[Subscription standalone]
  B --> C[Invoice generated]
  C --> D[Sent to delegated payer]
  D --> E[Payer wallet drawn down]
```

| Property            | Where it lives                             |
| ------------------- | ------------------------------------------ |
| Plan and line items | Subscription owner's subscription          |
| Usage tracking      | Subscription owner                         |
| Entitlements        | Subscription owner's subscription          |
| Invoice             | **Delegated payer**                        |
| Wallet              | **Delegated payer**                        |
| Tax                 | Based on delegated payer's billing details |

## When to use delegated invoicing

* **Reseller model**: A reseller signs up 10 end customers. Each customer has their own starter plan and usage. The reseller receives and pays all invoices centrally.
* **Central billing department**: A company's Finance team handles all vendor payments. Engineering, Marketing, and Sales each track their own usage, but invoices go to Finance.
* **Managed service provider**: An MSP provisions software for their clients. Each client has their own subscription, but the MSP is billed for all of them.

## Prerequisites

* Subscription owner (child) customer created in Flexprice
* Delegated payer customer created in Flexprice with a known `external_id`
* Delegated payer customer must have `status: published` (active) at the time the subscription is created
* A plan created in the product catalogue

<Note>
  On create, `invoicing_customer_external_id` cannot be combined with `external_customer_ids_to_inherit_subscription` or `subscriptions_ids_for_grouped_invoicing`.
</Note>

## Configure

<Tabs>
  <Tab title="Dashboard">
    1. Navigate to **Subscriptions** and click **Create Subscription**
    2. Select the **subscription owner** (end customer) as the customer
    3. Choose a plan
    4. In the **Invoice To** field, enter the delegated payer's external ID
    5. Click **Create Subscription**
  </Tab>

  <Tab title="API">
    ```bash theme={null}
    curl -X POST https://api.flexprice.io/v1/subscriptions \
      -H "Authorization: Bearer YOUR_API_KEY" \
      -H "Content-Type: application/json" \
      -d '{
        "external_customer_id": "ext-end-customer",
        "plan_id": "plan_starter_monthly",
        "currency": "usd",
        "billing_period": "month",
        "billing_period_count": 1,
        "start_date": "2026-06-01T00:00:00Z",
        "inheritance": {
          "invoicing_customer_external_id": "ext-reseller"
        }
      }'
    ```

    Response (abbreviated):

    ```json theme={null}
    {
      "id": "sub_01child",
      "subscription_type": "standalone",
      "customer_id": "cus_end_customer",
      "invoicing_customer_id": "cus_reseller",
      "status": "active"
    }
    ```
  </Tab>
</Tabs>

## Post-creation changes

The delegated payer is **immutable** after subscription creation. To change the invoicing customer, cancel the existing subscription and create a new one with the correct `invoicing_customer_external_id`.

## Analytics

Analytics work the same as standalone. Query the subscription owner's `external_customer_id` directly. No special flags are needed. Usage events are ingested under the subscription owner, not the delegated payer.

## Validations and constraints

<Warning>
  **Invoicing customer must be active.** The delegated payer must have `status: published` at creation time. Error: `"invoicing customer is not active"`. Resolve: activate the delegated payer customer before creating the subscription.
</Warning>

<Warning>
  **Invoicing customer is immutable.** The `invoicing_customer_external_id` cannot be changed after the subscription is created. To reassign, cancel and recreate the subscription.
</Warning>

<Note>
  **Subscription type.** The subscription owner's subscription will show `subscription_type: standalone`. This is correct. Delegated invoicing is not a separate type; it is a standalone subscription with an invoicing redirect.
</Note>

## Related workflows

<CardGroup cols={2}>
  <Card title="Consolidated Billing" icon="building-columns" href="/docs/subscriptions/billing-workflows/consolidated-billing">
    When one parent contract should cover multiple customers with a single plan
  </Card>

  <Card title="Grouped Invoicing" icon="layer-group" href="/docs/subscriptions/billing-workflows/grouped-invoicing">
    When separate subscriptions should merge into one invoice
  </Card>
</CardGroup>