# Upstream limits

> Staked sends and lookups past a region's ledger window have a burst rate and a sustained rate on each plan. A key over its sustained rate is slowed, never cut off.

Source: https://docs.constant-k.com/get-started/upstream-limits/

Staked sends and lookups past a region's ledger window go upstream. For these, each plan has two limits:

| Limit          | What it counts                                                                                     |
| :------------- | :------------------------------------------------------------------------------------------------- |
| Burst rate     | Calls per second, per region. It is the plan rate and always applies.                              |
| Sustained rate | The key's average over the last 24 hours, all regions together. Only calls that go upstream count. |

A key at or under its sustained rate is never slowed. A key over it is slowed step by step, and never cut off.

## Burst and sustained rates

<div className="relative overflow-auto prose-no-margin my-6">
  <table className="ck-bs">
    <thead>
      <tr>
        <th rowSpan="2">Method</th>

        <th colSpan="2">Operator</th>

        <th colSpan="2">Blade Runner</th>

        <th colSpan="2">Nexus</th>
      </tr>

      <tr>
        <th>Burst</th>

        <th>Sustained</th>

        <th>Burst</th>

        <th>Sustained</th>

        <th>Burst</th>

        <th>Sustained</th>
      </tr>
    </thead>

    <tbody>
      <tr>
        <td><code>sendTransaction</code> (staked)</td>

        <td>1 rps</td>

        <td>0.25 rps</td>

        <td>5 rps</td>

        <td>2 rps</td>

        <td>20 rps</td>

        <td>5 rps</td>
      </tr>

      <tr>
        <td><code>getSignaturesForAddress</code> (older signatures)</td>

        <td>—</td>

        <td>—</td>

        <td>—</td>

        <td>—</td>

        <td>30 rps</td>

        <td>2 rps</td>
      </tr>

      <tr>
        <td><code>getTransaction</code> (older transactions)</td>

        <td>—</td>

        <td>—</td>

        <td>—</td>

        <td>—</td>

        <td>100 rps</td>

        <td>3 rps</td>
      </tr>

      <tr>
        <td><code>getTransactionsForAddress</code> (signatures)</td>

        <td>—</td>

        <td>—</td>

        <td>—</td>

        <td>—</td>

        <td>30 rps</td>

        <td>3 rps</td>
      </tr>

      <tr>
        <td><code>getTransactionsForAddress</code> (full)</td>

        <td>—</td>

        <td>—</td>

        <td>—</td>

        <td>—</td>

        <td>5 rps</td>

        <td>3 rps</td>
      </tr>
    </tbody>
  </table>
</div>

Burst is per region. Sustained is the 24-hour average, all regions together. Both `getTransactionsForAddress` modes share one sustained rate.

`getBlock` for older blocks has a monthly allowance instead. See [Cube Runner limits](https://docs.constant-k.com/get-started/plans-and-limits/#cube-runner-limits).

## Which requests go upstream

| Request                                | Goes upstream                                                                                                                       |
| :------------------------------------- | :---------------------------------------------------------------------------------------------------------------------------------- |
| `sendTransaction` on a staked hostname | The staked path. See [Staked endpoints](https://docs.constant-k.com/rpc/sending-transactions/#staked-endpoints).                                               |
| `getSignaturesForAddress`              | Signatures past the region's ledger window. See [Historical lookups](https://docs.constant-k.com/rpc/http/getsignaturesforaddress/#historical-lookups).        |
| `getTransaction`                       | Transactions past the region's ledger window. See [Historical lookups](https://docs.constant-k.com/rpc/http/gettransaction/#historical-lookups).               |
| `getTransactionsForAddress`            | Address history past the region's ledger window. See [Historical lookups](https://docs.constant-k.com/rpc/http/gettransactionsforaddress/#historical-lookups). |
| `getBlock`                             | Blocks no region's cache or ledger holds, from long-term storage. See [Long-term storage](https://docs.constant-k.com/cube-runner/#long-term-storage).         |

## How a key is slowed

* A key over its sustained rate is never cut at once. Its allowed 24-hour average goes down by the same percentage each day for 7 days, until it reaches the sustained rate.
* The allowed average is shared out between regions by where the key's calls go. Every region keeps at least 0.1 calls per second.
* A slowed key keeps its burst rate. It can save up to 1 hour of its allowed rate for a burst.
* When the key's 24-hour average stays at or under its sustained rate for 6 hours in a row, its limit comes back step by step.

Example: a key averages 12 calls per second, and its sustained rate is 5 per second.

| Day   | Allowed 24-hour average |
| :---- | :---------------------: |
| Start |      12 per second      |
| 1     |     10.6 per second     |
| 2     |      9.3 per second     |
| 3     |      8.2 per second     |
| 4     |      7.3 per second     |
| 5     |      6.4 per second     |
| 6     |      5.7 per second     |
| 7     |       5 per second      |

## What happens when a key is slowed

Calls over the key's allowed rate are slowed, never stopped.

| Request                                      | Over the allowed rate                                                                                                                                                                       |
| :------------------------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `sendTransaction` (staked)                   | Still sent, from constant-k's own nodes instead of the staked path. See [When a staked send falls back](https://docs.constant-k.com/rpc/sending-transactions/#when-a-staked-send-falls-back).                          |
| `getSignaturesForAddress` (older signatures) | Waits up to 3 s for the key's next turn. If the next turn is later, only the signatures the region's own ledger holds. No error.                                                            |
| `getTransaction` (older transactions)        | Waits up to 3 s for the key's next turn. If the next turn is later, `null`. No error.                                                                                                       |
| `getTransactionsForAddress`                  | Waits up to 5 s for the key's next turn. If the next turn is later, HTTP `429` with code `-32005`. The `Retry-After` header and `error.data.retry_after` give the seconds to the next turn. |

## Your rates

The **Upstream** section of [My Account](https://www.constant-k.com/my-account/) shows, for each API key and method:

* A bar for each region: your rate over the last minute against your burst rate, with a mark at your 24-hour average.
* Your plan's sustained rate.
* A graph of your use over the past 24 hours, one line per region.
* When a key is slowed: a mark at its allowed 24-hour average on each bar, an alert, and a graph of the 7-day schedule that shows where the key is now, with a day-by-day table.

**Cube Runner** usage shows as one block per region: the blocks used this month against the plan's monthly allowance.