> ## 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.

# Overview

> API reference for the Billing APIs

The **Billing APIs** allow merchants to store and manage their customers, accounts, and bills within the Moment ecosystem, providing a foundation for building end-to-end billing experiences from account setup and bill generation to real-time tracking of payments and balances.

<div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-2 gap-6">
  <Card title="Quickstart: Customer Balance" icon="bolt" href="/api-reference/billing/quickstart-customer-balance">
    Accept a payment against a customer balance.
  </Card>

  <Card title="Quickstart: Account Balance" icon="bolt" href="/api-reference/billing/quickstart-account-balance">
    Track balances across sub-accounts within a customer.
  </Card>

  <Card title="Quickstart: Bill Amount Due" icon="bolt" href="/api-reference/billing/quickstart-bill-amount-due">
    Raise a bill with an amount due and track payment against it.
  </Card>

  <Card title="Common Operations" icon="code" href="/api-reference/billing/examples">
    Examples for updating customer balances, account balances, and bills.
  </Card>
</div>

<br />

<Note>
  Moment supports three billing models: **Customer Balance** (a single running balance per customer), **Account Balance** (separate balances across sub-accounts within a customer), and **Bill** (discrete invoices with their own amount due and lifecycle).<br /><br />The right model depends on your use case. See [Core Concepts](/documentation/billing/core-concepts) for a full explanation.
</Note>

<br />

👉 [See Product Guide](/documentation/billing/overview)

***

## APIs

<div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-2 gap-6">
  <Card title="Customers" icon="user" href="/api-reference/billing/customers/create">
    Create and manage top-level customer records.
  </Card>

  <Card title="Accounts" icon="folder" href="/api-reference/billing/accounts/create">
    Manage sub-customer accounts within a customer.
  </Card>

  <Card title="Bills" icon="file-invoice" href="/api-reference/billing/bills/create">
    Create, update, and track individual bills.
  </Card>
</div>

***

## Webhooks

The **Billing APIs** support webhook events that help you track billing-related lifecycle events in real time, including bill creation, status updates, and payment application.

These events can be used to trigger downstream workflows, notify customers, or reconcile internal records.

### Available Events

* **`obligation.amount_applied`**
  Triggered when an amount is received against an obligation (e.g., bill, customer, or account).
  👉 [See `obligation.amount_applied` Event](/api-reference/billing/webhook/obligation_amount_applied)

<Note>Events like `bill.created`, `bill.updated`, `customer.created`, and others are coming soon.</Note>

### Error Codes

👉 [See Common Error Codes](/api-reference/getting-started/errors)