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

# Oracles

Polymarket resolves its markets by using oracles.

### What is an oracle?

An oracle is a trusted source that provides the official outcome of events or real-world data such as prices and reported numbers. 

### Why does Polymarket use oracles?

Polymarket does not have a way of knowing real-world outcomes on its own. Oracles provide Polymarket with real-world outcomes so it knows how a market should resolve.

<figure><img src="/files/qHqPxsFJUeT8mJDUvx9G" alt=""><figcaption></figcaption></figure>

### Which oracles does Polymarket use?

Polymarket uses three oracles: the **Markets Team**, **Chainlink**, and **UMA Protocol**.&#x20;

### Markets Team

Polymarket has a Markets Team whose job is to create markets, write rulesets, and resolve markets.

<figure><img src="/files/zIWSwkIragapd6XEvGQH" alt=""><figcaption></figcaption></figure>

### Chainlink

[Chainlink](https://chain.link/) is the largest decentralized oracle network. It delivers secure, tamper-resistant data from outside sources into blockchain applications.

<figure><img src="/files/bFLblv8BFsTmaLRE66fC" alt=""><figcaption></figcaption></figure>

#### How does Chainlink work?&#x20;

Chainlink collects information, such as asset prices, from multiple independent providers. It then aggregates and delivers that data onchain in a way that is timestamped and verifiable, reducing the risk of errors or manipulation.

#### How does Polymarket use Chainlink?

Polymarket uses Chainlink to resolve markets that depend on real-time numbers like crypto prices. With the integration of **Chainlink Data Streams** (low-latency, verifiable price feeds) and **Chainlink Automation** (timely, automated onchain settlement), Polymarket can run fast-resolving markets such as **15-minute crypto price markets**.

### UMA Protocol

[UMA (Universal Market Access)](https://uma.xyz) is an optimistic oracle designed for questions where outcomes are harder to verify or do not have a single data source.

<figure><img src="/files/UVEeBXwDH8kDFLmx3VHc" alt=""><figcaption></figcaption></figure>

#### How does UMA work?&#x20;

UMA uses a **three-step process** to verify real-world outcomes and bring that data onto the blockchain:

* **Proposers** submit an answer to the market question.
* **Disputers** can challenge the answer if they believe it is wrong.
* **Voters** make the final decision if a dispute occurs.

This system creates checks and balances so that incorrect answers can be caught and corrected.

#### How does Polymarket use UMA?

Polymarket uses UMA for markets that cannot be resolved through automated data feeds like Chainlink. These are often **subjective questions** or situations where there is no single official source. By using UMA, Polymarket ensures that these markets still resolve in a transparent way, with the community involved in verifying the outcome.

### Polymarket US vs. Polymarket International

On **Polymarket US**, the Markets Team is responsible for resolving markets by checking whether the resolution criteria have been satisfied.&#x20;

On **Polymarket International**, the Markets Team provides clarifications about how a market should resolve, while the **UMA Oracle** performs the actual resolution process.

{% hint style="info" %}
**Going Forward**\
In the Resolution section, all mentions of "the oracle" refer to the **UMA Oracle**, unless otherwise noted.
{% endhint %}