> ## Documentation Index
> Fetch the complete documentation index at: https://datum-4926dda5-docs-api-reference-demo.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# BillingAccountBinding

> BillingAccountBinding links a project to a billing account, establishing billing responsibility for the project's resource consumption.

<Note>
  API resource reference for **BillingAccountBinding**, part of the [Billing service](/api/billing/overview). To create or change one, see [Changing resources](/datumctl/resources/changing); to inspect, see [Reading resources](/datumctl/resources/reading).
</Note>

<Warning>
  This resource is part of the `v1alpha1` API and is subject to change. Fields and behavior may change in future releases.
</Warning>

## Identity

|         |                         |
| ------- | ----------------------- |
| Group   | `billing.miloapis.com`  |
| Version | `v1alpha1`              |
| Kind    | `BillingAccountBinding` |
| Scope   | Project                 |

## Overview

A `BillingAccountBinding` connects a Project to a billing account so that the Project's resource consumption is charged to that account. Creating a binding establishes billing responsibility for the Project; the platform tracks which account is currently responsible and when that responsibility took effect.

All fields in the spec are immutable once the binding is created. To move a Project to a different billing account, create a new binding — the previous one moves to the `Superseded` phase.

## Spec fields

| Field                         | Type   | Required | Description                                            |
| ----------------------------- | ------ | -------- | ------------------------------------------------------ |
| `spec.billingAccountRef`      | Object | Yes      | References the billing account to bind.                |
| `spec.billingAccountRef.name` | string | Yes      | Name of the BillingAccount.                            |
| `spec.projectRef`             | Object | Yes      | References the project to bind to the billing account. |
| `spec.projectRef.name`        | string | Yes      | Name of the project.                                   |

## Status fields (read-only)

| Field                                         | Type      | Description                                                              |
| --------------------------------------------- | --------- | ------------------------------------------------------------------------ |
| `status.phase`                                | string    | Current lifecycle phase of the binding. One of `Active` or `Superseded`. |
| `status.billingResponsibility`                | Object    | Tracks when billing responsibility was established for this binding.     |
| `status.billingResponsibility.currentAccount` | string    | Name of the currently responsible billing account.                       |
| `status.billingResponsibility.establishedAt`  | string    | Time when billing responsibility was established.                        |
| `status.conditions`                           | \[]Object | Latest available observations of the binding's state.                    |
| `status.observedGeneration`                   | integer   | Most recent generation observed by the controller.                       |

## Usage

```yaml theme={null}
apiVersion: billing.miloapis.com/v1alpha1
kind: BillingAccountBinding
metadata:
  name: my-project-billing
spec:
  billingAccountRef:
    name: acme-billing-account
  projectRef:
    name: my-project
```

```bash theme={null}
datumctl apply -f billingaccountbinding.yaml --project my-project
datumctl get billingaccountbindings --project my-project
datumctl describe billingaccountbindings my-project-billing --project my-project
```

<Tip>
  Run `datumctl explain billingaccountbindings --recursive` to see the full, live field tree for this resource.
</Tip>