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

# Postpaid / Arrears

> Bill at the end of the period. For usage-based and enterprise contract billing.

Postpaid uses arrears billing: customers use your service first, then get invoiced at the end of the period. Combined with a 14-day grace period and lenient dunning, it's designed for enterprise contracts and usage-based SaaS.

## Who should use this

* Usage-based billing (API calls, seats consumed, storage used)
* Enterprise contracts with net-30 or net-60 payment terms
* Products where the invoice amount depends on activity during the period
* SaaS selling to procurement-driven organisations where the purchase order arrives after service delivery

## Settings

| Policy knob                   | Value                    | Why                                                                            |
| ----------------------------- | ------------------------ | ------------------------------------------------------------------------------ |
| Upgrade strategy              | Immediate, prorated      | Upgrade takes effect now                                                       |
| Downgrade strategy            | At period end            | Wait until the period closes                                                   |
| Grace period                  | 14 days                  | Enterprise payment cycles are slow — 14 days gives AP teams a realistic window |
| Dunning retries               | 4 (days +1, +3, +7, +14) | Standard retry schedule after invoice is created                               |
| Plan changes while `past_due` | Block upgrades           | Can't upgrade to a higher tier while the current invoice is unpaid             |
| **Billing mode**              | **Arrears**              | Invoice created at end of period, not start                                    |
| Max debt                      | None                     | —                                                                              |

## Apply

<CodeGroup>
  ```bash cURL theme={null}
  curl -X POST https://api.useplinth.com/v1/tenant/apply-preset \
    -H "Authorization: Bearer sk_test_DOCS_SHARED_KEY" \
    -H "Content-Type: application/json" \
    -d '{"preset": "postpaid"}'
  ```

  ```typescript Node.js theme={null}
  await client.tenant.applyPreset('postpaid');
  ```
</CodeGroup>

## How arrears changes the timeline

With this preset, a subscription created on June 1st works like this:

```
June 1: Subscription starts, access granted. No invoice yet.
July 1: Period ends. Invoice created for June. Collection starts.
July 15: Grace period expires if unpaid → delinquent.
```

Compare to advance billing: the invoice would be created and charged on June 1st.

<Note>
  If you're billing based on usage within the period (e.g., ₦50 per API call), you'll report usage via the metering API before the period closes. The invoice amount reflects the reported usage. See the metering docs for details.
</Note>