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

# Pre-paid credits and usage-based billing

> How pre-paid credits and usage-based billing work in Quo, formerly OpenPhone.

Pre-paid credits let you pay in advance for usage-based services like international calling, texting, and automations. This makes it easy to manage variable usage without affecting your regular subscription billing.

## What credits cover

* **International calling**: Per-minute rates vary by country
* **International texting**: Per-message rates vary by country
* **API messaging**: \$0.01 per message plus standard rates
* **Zapier automation**: \$0.01 per message plus standard rates

## How credits work

* **Per-usage deduction**: Credits consumed as you use services
* **Variable rates**: Each country has different calling/texting rates
* **Automatic billing**: Credits deducted from your balance automatically

***

## How to purchase pre-paid credits

1. Navigate to **Settings → Plan & billing**
2. Scroll to the **Voice & messaging balance**
3. Click **Add funds** to purchase

## Apply unused credits to your subscription

Have unused credits? Apply them to your subscription:

1. Navigate to **Settings → Plan & billing**
2. Scroll to the **Voice & messaging balance**
3. Click **Use towards subscription**
4. Confirm application

<Note>
  All credits are applied at once—you cannot specify a partial amount.
</Note>