> ## Documentation Index
> Fetch the complete documentation index at: https://docs.momentco.io/llms.txt
> Use this file to discover all available pages before exploring further.
# Quickstart: Bill Amount Due
> Raise a bill and track payment against it using the Billing API
This guide walks through the bill model: creating a customer, creating an account under that customer, raising a bill against the account with a specific amount due and due date, and handling the payment webhook. This model is suited for merchants who issue discrete invoices, where each bill represents a specific charge with its own lifecycle and payment status.
## Prerequisites
* A test API key. See [Authentication](/api-reference/getting-started/authentication).
* A registered webhook endpoint. See [Webhook Setup](/api-reference/webhooks/setup) to register your URL and obtain your signing key.
***
## Step 1: Create a customer
Create the top-level customer record.
```bash theme={"system"}
curl -X POST https://api.momentpay.net/billing/customers \
-H "Authorization: Bearer sk_test_YOUR_SECRET_KEY" \
-H "Content-Type: application/json" \
-d '{
"external_reference": "UCR1234567890",
"name": "John Doe",
"email": "john.doe@example.com"
}'
```
The response returns an `id`. Store this to reference the customer when creating the account.
```json theme={"system"}
{
"id": "bcus_H4jp6KnU5cPw263v1jyz4",
"external_reference": "UCR1234567890",
"name": "John Doe",
"email": "john.doe@example.com"
}
```
***
## Step 2: Create an account
Create an account under the customer. Bills will be raised against this account.
```bash theme={"system"}
curl -X POST https://api.momentpay.net/billing/accounts \
-H "Authorization: Bearer sk_test_YOUR_SECRET_KEY" \
-H "Content-Type: application/json" \
-d '{
"customer": "bcus_H4jp6KnU5cPw263v1jyz4",
"external_reference": "UAR1234567890",
"name": "Primary Account"
}'
```
The response returns an `id`. Store this to reference the account when creating the bill.
```json theme={"system"}
{
"id": "bacc_H4jp6KnU5cPw263v1jyz4",
"external_reference": "UAR1234567890",
"customer_id": "bcus_H4jp6KnU5cPw263v1jyz4",
"name": "Primary Account"
}
```
Steps 1 and 2 can be combined into a single request.
Instead of passing a `customer` ID when creating an account, pass a `customer` object with the same fields used in the create customer request.
Moment creates the customer first and then creates the account. See [Create Account](/api-reference/billing/accounts/create#body-customer-one-of-2).
***
## Step 3: Create a bill
Raise a bill against the account with an `amount_due`, `bill_date`, and `due_date`.
```bash theme={"system"}
curl -X POST https://api.momentpay.net/billing/bills \
-H "Authorization: Bearer sk_test_YOUR_SECRET_KEY" \
-H "Content-Type: application/json" \
-d '{
"account": "bacc_H4jp6KnU5cPw263v1jyz4",
"external_reference": "UBR1234567890",
"currency": "ZAR",
"amount_due": 2000,
"bill_date": "2025-01-01",
"due_date": "2025-01-31"
}'
```
`amount_due` is specified in minor units. See [Monetary Amounts](/api-reference/getting-started/monetary_amounts) for details.
The response returns an `id` and an initial `status` of `unpaid`. Store the `id` to match against the payment webhook.
```json theme={"system"}
{
"id": "bill_H4jp6KnU5cPw263v1jyz4",
"external_reference": "UBR1234567890",
"customer_id": "bcus_H4jp6KnU5cPw263v1jyz4",
"account_id": "bacc_H4jp6KnU5cPw263v1jyz4",
"status": "unpaid",
"amount_due": 2000,
"amount_paid": 0,
"amount_remaining": 2000,
"bill_date": "2025-01-01",
"due_date": "2025-01-31"
}
```
Bills can also be raised directly against a customer without an account.
To do so, replace `"account"` with `"customer"` in the request body and use the customer `id` from Step 1.
In that case, the response will only include `customer_id` and not `account_id`.
All three steps can be combined into a single create bill request.
Instead of passing an `account` ID, pass an `account` object — and nest a `customer` object within it.
Moment creates the customer, then the account, then the bill in sequence. See [Create Bill](/api-reference/billing/bills/create#body-customer-one-of-2) for the customer object and [Create Bill](/api-reference/billing/bills/create#body-account-one-of-2) for the account object.
***
## Step 4: Present the bill for payment
Present the bill for payment using [Electronic Bill Presentment](/documentation/billing/ebp) or a [Payment Request](/documentation/collect/payment-links/payment-requests).
***
## Step 5: Handle the payment webhook
When payment is received against the bill, Moment sends an `obligation.amount_applied` event.
```json theme={"system"}
{
"id": "evt_2341234567890abcdef",
"type": "obligation.amount_applied",
"data": {
"id": "ob_N2a38DJQWPL8K4X42354234",
"amount": 2000,
"currency": "ZAR",
"payment_id": "pay_1313235234843nmafdsa",
"account_id": "bacc_H4jp6KnU5cPw263v1jyz4"
}
}
```
Use `data.account_id` to identify which account the bill belongs to, and `data.amount` to update the bill's payment status.
If the bill was raised directly against a customer, the event will include `customer_id` instead of `account_id`.
Before processing, verify the event signature. See [Webhook Verification](/api-reference/webhooks/verification).
Respond with a `2xx` status code to acknowledge receipt.
***
## Next steps
Track a single running balance directly on a customer.
Track balances across multiple sub-accounts within a customer.
Present bills to customers via a hosted payment page.
Ingest bills in bulk via SFTP or file integration.
Examples for updating customer balances, account balances, and bills.