# Chainlink & Datafeeds

## Overview

Celestium games that depend on real-world prices — the [Predict Game](/dexgames/games-guide/predict-game.md) is the headline example — read those prices from Chainlink datafeeds. A Chainlink datafeed aggregates pricing from many independent sources and publishes a tamper-resistant value that any smart contract can consume.

## Reliable Price Data

Each Chainlink price feed pulls from premium data providers and runs the inputs through a decentralized network of oracle nodes. The published value is an aggregate the contract can read in a single call. There is no intermediary that can substitute a different number; the feed is its own source of truth.

## How It Works

1. **Aggregation** — independent oracle nodes pull the latest price from multiple data sources.
2. **Consensus** — nodes submit values on-chain; the feed contract aggregates them into a single canonical price.
3. **Consumption** — the Celestium game contract reads the canonical price at round-close time and uses it to settle the round.

<figure><img src="/files/1JpWAUor7w93cXlVpwAK" alt=""><figcaption><p>BTC/USD datafeed — example of a Chainlink price feed Celestium reads to settle Predict rounds</p></figcaption></figure>

## References

* Chainlink datafeeds — full list and live prices: <https://data.chain.link/>
* BTC/USD on Polygon — the canonical feed used to settle Predict rounds.

## Benefits

* **Reliability** — the published price reflects the live market within tight tolerances.
* **Security** — decentralized verification by independent oracle nodes prevents any single party from manipulating the value Celestium contracts consume.


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