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

# Network Configuration

> Configure blockchain networks for Watch Tower monitoring

# Network Configuration

Configure blockchain networks for Watch Tower monitoring.

## Overview

The Watch Tower monitors multiple blockchain networks simultaneously. Each network is configured in the `networks` array in your `config.json` file.

## Networks array structure

The configuration file contains a `networks` array where each element defines a blockchain network to monitor:

```json theme={null}
{
  "networks": [
    {
      "name": "mainnet",
      "rpc": "https://mainnet.infura.io/v3/YOUR_API_KEY",
      "deploymentBlock": 17883049,
      "filterPolicy": {
        "defaultAction": "ACCEPT"
      }
    }
  ]
}
```

## Per-network settings

Each network configuration supports the following fields:

### name

**Required** - String identifier for the network.

```json theme={null}
"name": "mainnet"
```

Supported network names:

* `mainnet` - Ethereum Mainnet
* `sepolia` - Ethereum Sepolia testnet
* `arbitrum_one` - Arbitrum One
* `avalanche` - Avalanche C-Chain
* `base` - Base
* `gnosis_chain` - Gnosis Chain
* `polygon` - Polygon PoS
* `linea` - Linea
* `plasma` - Plasma
* `ink` - Ink

### rpc

**Required** - RPC endpoint URL for connecting to the blockchain. Supports both HTTP(S) and WebSocket protocols.

HTTP RPC:

```json theme={null}
"rpc": "https://mainnet.infura.io/v3/YOUR_API_KEY"
```

WebSocket RPC:

```json theme={null}
"rpc": "ws://172.20.0.5:8546"
```

<Warning>
  Programmatic order types may consume considerable RPC calls. Ensure your RPC provider has sufficient rate limits.
</Warning>

### deploymentBlock

**Required** - Block number at which the ComposableCoW contract was deployed on the network.

This optimizes the watch-tower by only fetching events from the blockchain after this block number.

```json theme={null}
"deploymentBlock": 17883049
```

Refer to [Deployed Contracts](https://github.com/cowprotocol/composable-cow#deployed-contracts) for the correct deployment block for each chain.

### watchdogTimeout

**Optional** - Timeout in milliseconds for the watchdog timer. If the watch-tower doesn't process a block within this time, it will restart.

```json theme={null}
"watchdogTimeout": 300000
```

### processEveryNumBlocks

**Optional** - Throttle block processing to only process blocks every N blocks. Default is `1` (process every block).

Process every block:

```json theme={null}
"processEveryNumBlocks": 1
```

Process every other block:

```json theme={null}
"processEveryNumBlocks": 2
```

### orderBookApi

**Optional** - Custom URL for the CoW Protocol OrderBook API. If not specified, uses the default API for the network.

```json theme={null}
"orderBookApi": "https://api.cow.fi/mainnet/api/v1"
```

### pageSize

**Optional** - Number of blocks to fetch when querying historical events (`eth_getLogs`).

Default is `5000`, which is the maximum number of blocks that can be fetched in a single request from Infura.

Default (Infura-compatible):

```json theme={null}
"pageSize": 5000
```

No paging (own RPC node):

```json theme={null}
"pageSize": 0
```

<Info>
  If running against your own RPC node, you may set `pageSize` to `0` to fetch all blocks in one request instead of paging.
</Info>

### filterPolicy

**Required** - Defines filtering rules for programmatic orders. See [Filter policy configuration](/watch-tower/configuration/filter-policy) for details.

## Supported chains

Ethereum Mainnet:

```json theme={null}
{
  "name": "mainnet",
  "rpc": "https://mainnet.infura.io/v3/YOUR_API_KEY",
  "deploymentBlock": 17883049
}
```

Ethereum Sepolia:

```json theme={null}
{
  "name": "sepolia",
  "rpc": "https://sepolia.drpc.org",
  "deploymentBlock": 8468184
}
```

Arbitrum One:

```json theme={null}
{
  "name": "arbitrum_one",
  "rpc": "https://arb1.arbitrum.io/rpc",
  "deploymentBlock": 343493668
}
```

Avalanche:

```json theme={null}
{
  "name": "avalanche",
  "rpc": "https://avax-mainnet.g.alchemy.com/v2/YOUR_API_KEY",
  "deploymentBlock": 63235114
}
```

Base:

```json theme={null}
{
  "name": "base",
  "rpc": "https://mainnet.base.org",
  "deploymentBlock": 31084679
}
```

Gnosis Chain:

```json theme={null}
{
  "name": "gnosis_chain",
  "rpc": "https://rpc.gnosischain.com",
  "deploymentBlock": 40394915
}
```

Polygon:

```json theme={null}
{
  "name": "polygon",
  "rpc": "https://polygon-rpc.com",
  "deploymentBlock": 72315184
}
```

Linea:

```json theme={null}
{
  "name": "linea",
  "rpc": "https://rpc.linea.build",
  "deploymentBlock": 25028604
}
```

Plasma:

```json theme={null}
{
  "name": "plasma",
  "rpc": "https://rpc.plasma.to",
  "deploymentBlock": 4810535
}
```

Ink:

```json theme={null}
{
  "name": "ink",
  "rpc": "https://rpc-ten.inkonchain.com",
  "deploymentBlock": 37142449
}
```

## Example configuration

Complete example with multiple networks:

```json theme={null}
{
  "networks": [
    {
      "name": "mainnet",
      "rpc": "ws://172.20.0.5:8546",
      "deploymentBlock": 17883049,
      "pageSize": 5000,
      "processEveryNumBlocks": 1,
      "filterPolicy": {
        "defaultAction": "ACCEPT"
      }
    },
    {
      "name": "arbitrum_one",
      "rpc": "https://arb1.arbitrum.io/rpc",
      "deploymentBlock": 343493668,
      "filterPolicy": {
        "defaultAction": "ACCEPT"
      }
    }
  ]
}
```