> For the complete documentation index, see [llms.txt](/llms.txt).

# Enable API request forwarding

For JSON-RPC methods, you can request failover protection by adding the failover header to your API request using curl, Web3.js, Ethers.js, or any other language of your choice.

For more information about this feature, including our partner and their privacy information, see [Failover protection](/services/concepts/failover-protection/).

info

Failover support is available on Mainnet only.

## Request[​](#request "Direct link to Request")

In the code tabs, the `eth_blockNumber` method is used as an example.

- curl
- Web3.js
- Ethers.js

```
curl https://<network>.infura.io/v3/<YOUR-API-KEY> \
  -X POST \
  -H "Enable-Failover: true" \
  -d '{"jsonrpc": "2.0", "method": "eth_blockNumber", "params": [], "id": 1}'

```

```
const { Web3 } = require('web3')
const https = require('https')

const options = {
  headers: {
    'Enable-Failover': 'true',
  },
}

const provider = new https.Agent(options)

const web3 = new Web3(
  new Web3.providers.HttpProvider('https://<network>.infura.io/v3/<YOUR-API-KEY>', {
    agent: provider,
  })
)

web3.eth.getBlockNumber().then(console.log)

```

```
const ethers = require('ethers')
const fetch = require('node-fetch')

class InfuraJsonRpcProvider extends ethers.providers.JsonRpcProvider {
  constructor(network, apiKey) {
    super(network, apiKey)
    this.fetchFunc = async (url, json, processFunc) => {
      const response = await fetch(url, {
        method: 'POST',
        body: json.body,
        headers: {
          'Content-Type': 'application/json',
          'Enable-Failover': 'true',
        },
      })

      const text = await response.text()
      const fetchJsonResponse = {
        jsonrpc: json.jsonrpc,
        id: json.id,
        result: JSON.parse(text).result,
        error: JSON.parse(text).error,
      }

      return processFunc(fetchJsonResponse)
    }
  }
}

const provider = new InfuraJsonRpcProvider('https://<network>.infura.io/v3/<YOUR-API-KEY>')

provider.getBlockNumber().then(blockNumber => {
  console.log(blockNumber)
})

```