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Run an Ethereum Client

Chainlink nodes must be able to connect to an Ethereum client with an active websocket connection. This is accomplished by running both an execution client and a consensus client. You can run these clients yourself, but running Ethereum clients requires significant storage and network resources. Optionally, you can use External Services that manage these clients for you.

Geth

You can use the Geth client for the Sepolia testnet and the Ethereum Mainnet. See the Geth Documentation for a list of supported networks.

Download the latest version:

docker pull ethereum/client-go:latest

Create a local directory to persist the data:

mkdir ~/.geth-sepolia

Run the container:

docker run --name eth -p 8546:8546 -v ~/.geth-sepolia:/geth -it \
ethereum/client-go --sepolia --ws --ipcdisable \
--ws.addr 0.0.0.0 --ws.origins="*" --datadir /geth

Once the Ethereum client is running, you can use Ctrl + P, Ctrl + Q to detach from the container without stopping it. You will need to leave the container running for the Chainlink node to connect to it.

If the container was stopped and you need to run it again, you can simply use the following command:

docker start -i eth

Follow Geth's instructions for Connecting to Consensus Clients. This will require some additional configuration settings for the Docker command that runs Geth.

Return to Running a Chainlink Node.

Nethermind

You can use the Nethermind client for the Ethereum Mainnet. See the Nethermind supported network configurations page for a list of supported networks.

Download the latest version:

docker pull nethermind/nethermind:latest

Create a local directory to persist the data:

mkdir ~/.nethermind-sepolia

Run the container:

docker run --name eth -p 8545:8545 \
-v ~/.nethermind-sepolia/:/nethermind/data \
-it nethermind/nethermind:latest --config sepolia \
--Init.WebSocketsEnabled true --JsonRpc.Enabled true \
--JsonRpc.Host 0.0.0.0 --NoCategory.CorsOrigins * \
--datadir data

After the Ethereum client is running, you can use Ctrl + P, Ctrl + Q to detach from the container without stopping it. You will need to leave the container running for the Chainlink node to connect to it.

If the container was stopped and you need to run it again, use the following command to start it:

docker start -i eth

Follow Nethermind's instructions for Installing and configuring the Consensus Client. This will require some additional configuration settings for the Docker command that runs Nethermind.

Return to Running a Chainlink Node.

External Services

The following services offer Ethereum clients with websockets connectivity known to work with the Chainlink node.

Alchemy

Example connection setting:

ETH_URL=wss://eth-sepolia.alchemyapi.io/v2/YOUR_PROJECT_ID

Chainstack

Example connection setting:

ETH_URL=wss://user-name:pass-word-pass-word-pass-word@ws-nd-123-456-789.p2pify.com

Fiews

Example connection setting:

ETH_URL=wss://cl-main.fiews.io/v2/YOUR_API_KEY

GetBlock

Example connection setting:

ETH_URL=wss://eth.getblock.io/sepolia/?api_key=YOUR_API_KEY

Infura

Example connection setting. Replace YOUR_PROJECT_ID with the ID Infura provides you on your project settings page.

ETH_URL=wss://sepolia.infura.io/ws/v3/YOUR_PROJECT_ID

LinkPool

Example connection setting:

ETH_URL=wss://main-rpc.linkpool.io/ws

QuikNode

Example connection setting:

ETH_URL=wss://your-node-name.sepolia.quiknode.pro/security-hash/

Configuring your ETH node

At a minimum, disable the default RPC gas and txfee caps on your ETH node. This can be done in the TOML file as seen below, or by running go-ethereum with the command line arguments: --rpc.gascap=0 --rpc.txfeecap=0.

To learn more about configuring ETH nodes, see the configuration page.

Additional Tools

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