> For the complete documentation index, see [llms.txt](https://docs.ethgas.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ethgas.com/overview/realtime/run-a-node-for-node-operators.md).

# Run a Node (for Node Operators)

How to run an ethgas-node with flashblocks enabled, so it serves pre-confirmed state at the pending tag. Flashblocks are off by default. Without a flashblocks feed the node behaves as an ordinary Ethe

### Run it

```
git clone https://github.com/ethgas-developer/ethgas-reth.git
cd ethgas-reth
cargo build --release --bin ethgas-node

./target/release/ethgas-node node \
  --chain hoodi \
  --flashblocks-url wss://hoodi.flashblocks.ethgas.com/ws \
  --engine.persistence-threshold 0 \
  --engine.memory-block-buffer-target 0 \
  --http --http.api eth,net,web3 \
  --ws --ws.api eth,net,web3
```

***

### Flashblocks flags

| Flag                                | Description                                                                                                                  | Default    |
| ----------------------------------- | ---------------------------------------------------------------------------------------------------------------------------- | ---------- |
| `--flashblocks-url <URL>`           | WebSocket endpoint streaming flashblocks. Alias `--websocket-url`. Setting it enables the feature                            | *disabled* |
| `--max-pending-blocks-depth <N>`    | Pending blocks held in memory                                                                                                | `3`        |
| `--flashblocks.ping-interval <DUR>` | Ping interval, and also the pong deadline. A dead feed is detected after at most two intervals. Requires `--flashblocks-url` | `2s`       |

***

### Flashblocks endpoints

Point `--flashblocks-url` at the endpoint for the network you are running.

| Network | Endpoint                                  |
| ------- | ----------------------------------------- |
| Mainnet | `wss://mainnet.flashblocks.ethgas.com/ws` |
| Hoodi   | `wss://hoodi.flashblocks.ethgas.com/ws`   |

> **These are node infrastructure, not application endpoints.** Your users should query your RPC. Do not point an application at the stream directly, and do not expose it to them.

**Serve WebSocket as well as HTTP.** The flashblock subscriptions need `--ws`. They cannot be served over HTTP.

***

### The two engine flags

`--engine.persistence-threshold 0` and `--engine.memory-block-buffer-target 0` are not cosmetic. They make the node persist blocks immediately rather than hold them in memory, which is what keeps pre-confirmed state anchored to the block it was built on. Running with the defaults risks `pending` silently falling back to the latest confirmed block.


---

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