> ## 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

> Configure op-reth as your OP Stack execution client. op-geth support ends 2026-05-31.

The execution client provides the EVM runtime and transaction processing for your OP Stack node.

<Warning>
  **op-geth reaches end-of-support on 2026-05-31 and will not support the L1 Glamsterdam hardfork.** Chains still running op-geth at activation will not follow the canonical chain. Migrate to op-reth — see the [op-geth deprecation notice](/notices/op-geth-deprecation).
</Warning>

<Info>
  Always run your execution client and consensus client in a 1:1 configuration. Don't run multiple execution clients behind one consensus client, or vice versa.
</Info>

## Execution clients

<Tabs>
  <Tab title="op-reth">
    [op-reth](https://github.com/paradigmxyz/reth) is a Rust-based execution client and the primary supported path for OP Stack nodes going forward.

    ### Minimal configuration

    ```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
    ```

    ### Historical proofs

    Permissionless chains need \~28 days of historical state for withdrawal proving. Follow the [Running op-reth with Historical Proofs](/node-operators/tutorials/reth-historical-proofs) tutorial to set up the `--proofs-history` (v2) store on op-reth v2.2.3 or later.

    ### Complete reference

    * [op-reth configuration reference](/node-operators/reference/op-reth-config)
    * [op-reth historical proof configuration](/node-operators/reference/op-reth-historical-proof-config)
    * [reth.rs documentation](https://reth.rs/run/opstack)
  </Tab>

  <Tab title="Nethermind">
    [Nethermind](https://github.com/NethermindEth/nethermind) is a .NET-based alternative execution client.

    ### Minimal configuration

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

    ### Additional resources

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

## JWT secret

The execution client and consensus client communicate over the Engine API using a shared JWT secret:

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

This file must be identical for both your execution client and your consensus client.

## op-geth (legacy — end of support 2026-05-31)

<Warning>
  op-geth support ends on **2026-05-31** and **will not support the Glamsterdam hardfork**. For new deployments, use op-reth (above). See the [op-geth deprecation notice](/notices/op-geth-deprecation) for the migration plan.
</Warning>

<Accordion title="op-geth configuration (legacy)">
  [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

  ```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
  ```

  Defaults: snap sync mode, no WebSocket server, no metrics.

  ### OP Stack specific flags

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

  ### Complete reference

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