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Configure Teku to use a builder network

You can connect to a builder network to generate execution payloads for the consensus client.

The builder recommends new blocks that are validated by the consensus client. If the builder goes down, the local execution client proposes a block instead.

Use the following steps to configure Teku to use a builder network.

1. Enable blinded block production​

Enable blinded block production using the --validators-proposer-blinded-blocks-enabled command line option.

note

If --validators-builder-registration-default-enabled is set to true, then --validators-proposer-blinded-blocks-enabled is automatically enabled.

2. Specify the builder endpoint​

Specify the builder endpoint using the --builder-endpoint command line option. For example:

--builder-endpoint="https://builder-relay-sepolia.flashbots.net/"

View the list of relay endpoints for available endpoints.

You can also use external software such as MEV-Boost to connect to multiple relays. For example:

--builder-endpoint=http://127.0.0.1:18550

3. Register the validator​

You must register your validator with the builder before proposing a block. On the validator client, enable registration for all validators using the --validators-builder-registration-default-enabled command line option.

To enable registration for specific validators only, use the --validators-proposal-config option and specify the enabled validators in the proposer_config field of the proposer configuration file.

proposerConfig.json
{
  "proposer_config": {
    "0xa057816155ad77931185101128655c0191bd0214c201ca48ed887f6c4c6adf334070efcd75140eada5ac83a92506dd7a": {
      "fee_recipient": "0x50155530FCE8a85ec7055A5F8b2bE214B3DaeFd3",
      "builder": {
        "enabled": true,
        "gas_limit": "12345654321"
      }
    }
  },
  "default_config": {
    "fee_recipient": "0x6e35733c5af9B61374A128e6F85f553aF09ff89A",
    "builder": {
      "enabled": false
    }
  }
}

In this example, validator 0xa057816... is registered with the builder, but any validator using the default configuration isn't.

note

If you use a proposer configuration, you must enable blinded block production using --validators-proposer-blinded-blocks-enabled.

Example builder configurations​

In the following example, Teku is running with the beacon node and validator client in a single process.

teku \
    --ee-endpoint="http://127.0.0.1:8551"                  \
    --ee-jwt-secret-file="/etc/jwt-secret.hex"             \
    --validators-builder-registration-default-enabled=true \
    --builder-endpoint="http://127.0.0.1:18550"            \
    --validators-proposer-default-fee-recipient="0x6e35733c5af9B61374A128e6F85f553aF09ff89A"

In the following example, Teku is running with the beacon node and validator client in separate processes. The beacon node runs with no validators in a single process, and the validator client maintains keys in a separate process. The proposer configuration is managed using a proposer configuration file, and the validator client communicates with the beacon node using REST API.

teku \
    --rest-api-enabled=true                     \
    --ee-endpoint="http://127.0.0.1:8551"       \
    --ee-jwt-secret-file="/etc/jwt-secret.hex"  \
    --builder-endpoint="http://127.0.0.1:18550" \
    --validators-proposer-default-fee-recipient="0x6e35733c5af9B61374A128e6F85f553aF09ff89A"

In the following example, a validator client is connected to a beacon node that is using the builder flow, and all keys use a specified fee recipient from the validator client by default. Each epoch, the validator client will register all of its keys to the specified fee recipient with the beacon node.

teku \
    --rest-api-enabled=true                     \
    --ee-endpoint="http://127.0.0.1:8551"       \
    --ee-jwt-secret-file="/etc/jwt-secret.hex"  \
    --builder-endpoint="http://127.0.0.1:18550" \
    --validators-proposer-default-fee-recipient="0x6e35733c5af9B61374A128e6F85f553aF09ff89A"