# Chainlink Oracle

Chainlink Oracle is currently used as the default module for providing block headers in Futaba. Specifically, it requests a job that can be configured in the Chainlink Node to execute an API to retrieve block headers configured as an External Adapter and return them to the contract.

{% embed url="<https://docs.chain.link/chainlink-nodes/external-adapters/external-adapters>" %}

{% @mermaid/diagram content="graph RL;
subgraph Src chain
G\[Gateway Contract]<-->|9. verify proofs|L\[LightClient Contract];
end

```
subgraph Off-chain
	G-->|1. emit event|R((Relayer));
	L-->|2. emit event|C{Chainlink Oracle};
	C-->|5. return and store state root|L
	R-->|8. return account and storage proof and value|G
end

subgraph Destination chain
	C-->|3. query state root|T[Target Contract]
	T-->|4. return state root|C
	R-->|6. query account and storage proof|T
	T-->|7. return account and storage and value|R
end" %}
```

In the case of Chainlink, the state root is directly obtained and stored, not the block header.