> For the complete documentation index, see [llms.txt](https://gitbook.humanode.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gitbook.humanode.io/docs/tools-and-services/oracles.md).

# Oracles

## What is an Oracle

Blockchain applications and smart contracts often need data that is not directly originates on the chain. For example an exchange rate of the fiat currencies that are not traded on the chain, or, another example, the temperature in a particular location at a given day in the past.

Oracles are a part of the blockchain ecosystem that provide on-chain access to such data. In particular, roughly, any piece of data that can be objectively agreed upon by multiple independent verifiers, who then are able to collectively witness and attest the correct upload of the said piece of data on chain.

## Oracles on the Humanode chain

Humanode chain has officially partnered with [Supra Oracles](https://supra.com/).

### Supra Oracles - Pull Oracle v2

{% tabs %}
{% tab title="Mainnet" %}

<table><thead><tr><th width="134">Contract</th><th>Address</th></tr></thead><tbody><tr><td>storage</td><td><code>0x58e158c74DF7Ad6396C0dcbadc4878faC9e93d57</code></td></tr><tr><td>pull</td><td><code>0x8B506d2616671b6742b968C18bEFdA1e665A9025</code></td></tr></tbody></table>
{% endtab %}

{% tab title="Testnet 5" %}

<table><thead><tr><th width="135">Contract</th><th>Address</th></tr></thead><tbody><tr><td>storage</td><td><code>0x5df499C9DB456154F81121282c0cB16b59e74C4b</code></td></tr><tr><td>pull</td><td><code>0x30484f27c5191A34587007aD380049d54DbCfAE7</code></td></tr></tbody></table>
{% endtab %}
{% endtabs %}

Check their documentation below:

{% embed url="<https://supra.com/docs/data-feeds/pull-model/>" %}