> ## Documentation Index
> Fetch the complete documentation index at: https://docs.optimism.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Execution client configuration

> Learn how to configure execution clients (op-geth, op-reth, Nethermind) for your OP Stack node.

The execution client provides the EVM execution environment and processes transactions.
This guide covers configuration for the most popular execution client implementations.

<Info>
  Always run your execution client and consensus client in a one-to-one configuration.
  Don't run multiple execution client instances behind one consensus client, or vice versa.
</Info>

## Execution clients

Choose the execution client that best fits your needs:

<Tabs>
  <Tab title="op-geth">
    ## op-geth configuration

    [op-geth](https://github.com/ethereum-optimism/op-geth) is a minimal fork of go-ethereum optimized for the OP Stack.

    <Info>
      Although the Docker image is called `op-geth`, the actual binary is still named `geth` to minimize differences from go-ethereum.
      See the [op-geth diff viewer](https://op-geth.optimism.io/?utm_source=op-docs\&utm_medium=docs) for details.
    </Info>

    ### Minimal configuration

    Minimumal configuration for op-geth:

    ```bash theme={null}
    geth \
      --datadir=/data/optimism \
      --http \
      --http.addr=0.0.0.0 \
      --http.port=8545 \
      --http.api=eth,net,web3 \
      --authrpc.jwtsecret=/path/to/jwt-secret.txt \
      --op-network=op-mainnet \
      --rollup.sequencerhttp=https://mainnet-sequencer.optimism.io/ \
      --rollup.disabletxpoolgossip 
    ```

    This will utilize primarily the default settings i.e. snap sync mode, no WebSocket server, no metrics, etc.

    ### OP Stack specific flags

    * `--rollup.sequencerhttp`: HTTP endpoint of the sequencer for transaction submission
    * `--rollup.disabletxpoolgossip`: Disables transaction pool gossip (recommended for replica nodes)
    * `--rollup.historicalrpc`: Enables historical RPC endpoint for upgraded networks (OP Mainnet pre-bedrock archive nodes)

    This file must be identical for both op-geth and your consensus client.

    ### Complete reference

    For all available configuration options, see the [op-geth configuration reference](/node-operators/reference/op-geth-config).
  </Tab>

  <Tab title="op-reth">
    ## op-reth configuration

    [op-reth](https://github.com/paradigmxyz/reth) is a Rust-based execution client optimized for performance.

    ### Minimal configuration

    Minimum required flags for op-reth:

    ```bash theme={null}
    op-reth node \
      --chain optimism \
      --rollup.sequencer https://mainnet-sequencer.optimism.io \
      --http \
      --ws \
      --authrpc.port 9551 \
      --authrpc.jwtsecret /path/to/jwt.hex
    ```

    ### Complete reference

    For all available configuration options, see the [op-reth configuration reference](/node-operators/reference/op-reth-config).
    If you are using the `op-rs` fork for historical proofs, see the [historical proof configuration](/node-operators/reference/op-reth-historical-proof-config).

    ### Additional resources

    For more details on op-reth configuration:

    * [op-reth documentation](https://reth.rs/run/opstack)
    * [op-reth configuration documentation](https://reth.rs/run/configuration)
  </Tab>

  <Tab title="Nethermind">
    ## Nethermind configuration

    [Nethermind](https://github.com/NethermindEth/nethermind) is a .NET-based execution client with enterprise features.

    ### Installation

    Download Nethermind from the [releases page](https://github.com/NethermindEth/nethermind/releases) or build from source.

    ### Initialization

    Nethermind uses a configuration file approach. Create a configuration file or use command-line flags.

    ### Minimal configuration

    Minimum required flags for Nethermind:

    ```bash theme={null}
    nethermind \
      -c op-mainnet \
      --data-dir path/to/data/dir \
      --jsonrpc-jwtsecretfile path/to/jwt.hex
    ```

    ### Additional resources

    For more details on Nethermind configuration:

    * [Nethermind documentation](https://docs.nethermind.io/get-started/running-node/l2-networks)
    * [Nethermind configuration reference](https://docs.nethermind.io/fundamentals/configuration)
  </Tab>
</Tabs>

## JWT secret

To communicate with consensus client and enable the Engine API, you'll also need to generate a JWT secret file and enable the execution client's authenticated RPC endpoint.
To generate the JWT secret file:

```bash theme={null}
openssl rand -hex 32 > jwt-secret.txt
```