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

# API Credits

> Every request costs 10 credits. How the balance is tracked, what happens when it runs out, and when credits are refunded.

## Every request costs 10 credits

Every authenticated request consumes **exactly 10 credits**. The cost does not change with
the size of the response, the width of the `startDate`/`endDate` window, the timeframe, or
which endpoint you call. A one-day series and a ten-year series cost the same.

This makes usage predictable: divide your credit balance by 10 and you have your request
count.

| Plan             |              Credits |   Requests |
| ---------------- | -------------------: | ---------: |
| **Free**         | 10,000, granted once |  **1,000** |
| **Professional** |       50,000 / month |  **5,000** |
| **Max**          |      200,000 / month | **20,000** |
| **Enterprise**   |           negotiated | negotiated |

## Reading your balance

Every response carries the remaining balance in a header:

```
X-Credits-Remaining: 4821
```

There is no need to poll a separate endpoint — read the header on the responses you are
already making.

## Failed requests are refunded

If a request comes back with anything other than a `2xx` status, the credit is returned to
your balance automatically. Errors on our side, validation failures and not-found responses
do not cost you credits.

## When the balance runs out

Once consumption reaches your allocation, further requests are rejected with **HTTP 402**:

```json theme={null}
{
  "errorCode": "InsufficientCredits",
  "message": "Insufficient API credits. Please purchase more credits or wait for your next billing cycle."
}
```

The request is not served and no credit is consumed. Existing keys keep working the moment
more credits are added or the cycle rolls over.

## Allocation and renewal

Your balance is the sum of two parts:

* **Plan allocation** — granted by your subscription, in the table above.
* **Top-ups** — extra credits added to the current period.

On a paid plan, consumption is counted per billing period, anchored on your billing cycle
day: when a new period starts, consumption resets to zero and the allocation applies again.

The free grant is **not** a monthly allowance — it is a single pool that does not renew.
Top-ups add to whichever of the two applies to you.

## If credit tracking is unavailable

Credit accounting is durable and enforced before the request runs. In the rare case the
accounting layer cannot be reached, the API answers **HTTP 503** with
`DurableCreditTrackingUnavailable` rather than serving a request it cannot account for.

<Note>
  Credits and rate limits are separate controls. Credits cap how much you consume over a
  billing period; rate limits cap how fast. See [Rate Limits](/rate-limits).
</Note>