> For the complete documentation index, see [llms.txt](https://docs.nebulablock.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nebulablock.com/getting-started/get-started/billing.md).

# Billing

How credits work on Nebula Block: payment cards, USDC, purchasing credit, auto-pay, invoices, and usage.

Everything on Nebula Block is paid for with **credits**. You buy credits up front, and usage — per-token inference, hourly instance charges, object storage egress — is deducted from that balance. Invoices are generated automatically for each purchase.

All of it is managed under [**Billing**](https://console.nebulablock.com/billing) in the console.

> **Note:** How much credit you have deposited or spent also determines your [tier](/account/tiers-and-limits.md), which sets your rate limits and whether you can rent CPU and GPU instances. How *much* GPU you can run at once is governed separately by your [hourly spending limit](/getting-started/get-started/spending-limits.md).

## Adding a Payment Card

To add a payment card, simply navigate to the "Add a New Card" button on the billing page and enter your card details. If the card meets the following requirements, it is added to your account successfully:

* Has valid card credentials (CVV, address, card number, etc.)
* Doesn't exist on another account
* Has enough funds available

Nebula Block accepts all types of payment cards. Note that your card may be validated for authenticity, but you will not be charged any amount during this process.

## Redeeming a Promotion Code

You can redeem a promotion code on the billing page. Simply enter your code in the "Add Promotion Code" section and click "Redeem" to apply the promotion to your account.

## Managing Payment Methods

Managing payment methods is simple via our customer portal. To change your default payment method, simply configure this in the [**Payment Method**](https://console.nebulablock.com/billing) section of the billing page.

## Purchasing Credits

Select the amount you want on the billing page and pay with your default card, a new card, or **USDC** if you prefer to pay in crypto.

## Configuring Auto-Pay

You can enable automatic billing (Auto-Pay) on the billing page. By adding a card to your account and configuring your Auto-Pay settings, your balance will be automatically reloaded when it nears your specified threshold. When your account balance falls below your chosen threshold, your default saved card will be charged the amount you set for Auto-Pay (maximum once per hour).

To set up Auto-Pay, toggle the Auto-Pay switch, set your threshold and reload amount, and save.

> **Important:** GPU and CPU instances are **deleted automatically if your credit runs out**. If you have anything long-running, turn Auto-Pay on — or watch for the low-balance alerts the console sends.

## Hourly Spending Limit

Every account has a ceiling on what its running instances may cost per hour, added together. New accounts start at **$5/hour** — which covers every single-GPU machine we offer — and the limit rises automatically as card payments settle, or on request. The **Hourly Spending Limit** card on the billing page shows your current limit, how much of it is in use, and lets you ask for more. Details: [Spending Limits](/getting-started/get-started/spending-limits.md).

## Invoices

Transactions made on your account (e.g. when you are billed for usage) will be documented as downloadable invoices and listed in the [**Transaction**](https://console.nebulablock.com/billing) section of the billing page.

## Usage

The [**Usages**](https://console.nebulablock.com/billing) section of the billing page breaks down what your credit is being spent on. For inference specifically, [Inference Usage](https://console.nebulablock.com/inference-usage) shows consumption by model and by API key.

## Credit limits

Each tier caps how much credit your account can hold — $20 at Tier 1 up to $2,000 at Tier 4. See [Tiers and Rate Limits](/account/tiers-and-limits.md).

## See also

* [Spending Limits](/getting-started/get-started/spending-limits.md)
* [Tiers and Rate Limits](/account/tiers-and-limits.md)
* [Billing API](/api-reference/platform-api/get-credit-balance.md)
* [Refund Policy](/resources/legal/refund-policy.md)