# Running an Op-node

To run an op-node alongside Erigon, follow these steps:

1. **Start Erigon with Caplin Enabled**: If Caplin is running as the consensus layer (CL), use the `--caplin.blobs-immediate-backfill` flag to ensure the last 18 days of blobs are backfilled, which is critical for proper synchronization with the op-node, assuming you start from a snapshot.

   ```bash
   ./build/bin/erigon --caplin.blobs-immediate-backfill
   ```
2. **Run the Op-Node**: Configure the op-node with the `--l1.trustrpc` flag to trust the Erigon RPC layer as the L1 node. This setup ensures smooth communication and synchronization.

This configuration enables the op-node to function effectively with Erigon serving as both the L1 node and the CL.