> For the complete documentation index, see [llms.txt](https://docs.getblock.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.getblock.io/api-reference/somnia/eth_chainid-somnia.md).

# eth\_chainId - Somnia

Example code for the eth\_chainId JSON-RPC method. Complete guide on how to use eth\_chainId JSON-RPC in GetBlock Web3 documentation.

This method returns the chain ID of the Somnia network. The chain ID is used to prevent replay attacks across different EVM networks. Somnia Mainnet uses chain ID 5031, while the Shannon Testnet uses 50312. This value is essential for transaction signing and network identification.

## Parameters

* None

## Returns

| Field  | Type   | Description                          |
| ------ | ------ | ------------------------------------ |
| result | string | The chain ID as a hexadecimal string |

## Request Example

{% tabs %}
{% tab title="cURL" %}

```bash
curl -X POST https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/ \
-H "Content-Type: application/json" \
-d '{
  "jsonrpc": "2.0",
  "id": "getblock.io",
  "method": "eth_chainId",
  "params": []
}'
```

{% endtab %}

{% tab title="JavaScript (Axios)" %}

```javascript
const axios = require('axios');

const url = 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/';

const payload = {
  jsonrpc: '2.0',
  id: 'getblock.io',
  method: 'eth_chainId',
  params: []
};

axios.post(url, payload, {
  headers: { 'Content-Type': 'application/json' }
})
.then(response => console.log(response.data))
.catch(error => console.error(error));
```

{% endtab %}

{% tab title="Python" %}

```python
import requests
import json

url = "https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/"

payload = {
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "method": "eth_chainId",
    "params": []
}

response = requests.post(url, headers={"Content-Type": "application/json"}, json=payload)
print(response.json())
```

{% endtab %}

{% tab title="Rust" %}

```rust
use reqwest::Client;
use serde_json::json;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = Client::new();
    
    let payload = json!({
        "jsonrpc": "2.0",
        "id": "getblock.io",
        "method": "eth_chainId",
        "params": []
    });

    let response = client
        .post("https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&payload)
        .send()
        .await?;

    let result: serde_json::Value = response.json().await?;
    println!("{:#?}", result);
    
    Ok(())
}
```

{% endtab %}
{% endtabs %}

## Response Example

```json
{
  "jsonrpc": "2.0",
  "id": "getblock.io",
  "result": "0x13a7"
}
```

## Response Parameters

| Parameter | Type   | Description                                 |
| --------- | ------ | ------------------------------------------- |
| result    | string | Chain ID in hex (0x13a7 = 5031 for Mainnet) |

## Use Cases

* Verify connection to correct network
* Include in transaction signing for replay protection
* Validate RPC endpoint configuration
* Network detection in multi-chain applications
* Wallet network switching

## Error Handling

| Error Code | Description                             |
| ---------- | --------------------------------------- |
| -32603     | Internal error - node processing issues |
| -32000     | Server error - RPC endpoint unavailable |

## SDK Integration

{% tabs %}
{% tab title="Ethers.js" %}
{% code overflow="wrap" %}

```javascript
const { ethers } = require('ethers');

const provider = new ethers.JsonRpcProvider('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/');

const network = await provider.getNetwork();
console.log(network.chainId); // 5031n for Mainnet
```

{% endcode %}
{% endtab %}

{% tab title="Viem" %}

```javascript
import { createPublicClient, http } from 'viem';
import { somnia } from 'viem/chains';

const client = createPublicClient({
  chain: somnia,
  transport: http('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/')
});

const chainId = await client.getChainId();
console.log(chainId); // 5031 for Mainnet
```

{% endtab %}
{% endtabs %}