> For the complete documentation index, see [llms.txt](https://andrecronje.gitbook.io/yearn-finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://andrecronje.gitbook.io/yearn-finance/developers/misc-resources/smart-contract-integration/fulcrum.md).

# fulcrum

{% tabs %}
{% tab title="Fulcrum.sol" %}

```javascript
// Solidity Interface

interface Fulcrum {
  function supplyInterestRate() external view returns (uint256);
}
```

{% endtab %}
{% endtabs %}