How to find if a block is finalized

Question

Is there a simple way to find out if a given block is finalized in PoS Ethereum?

Currently, I'm calling the endpoint ../eth/v1/beacon/states/finalized/finality_checkpoints of the Beacon Node and it delivers me the number of latest finalized Epoch.

After that, I'm using the returned Epoch number to get all blocks using an endpoint provided by beaconcha.in https://beaconcha.in/api/v1/epoch/<epoch-number>/blocks which lists all the Blocks in that Epoch

And the last step I do is check if the number of my block is smaller than the lowest blocknumber in the Epoch.

I'm looking for a simpler way to get that information using a library or the Beacon Node or execution Node or some API providers like Etherscan, Infura, beaconcha.in, etc...

Thanks

Answer 1

I have found another way using the latest version of Web3js 1.8.0. They added a new BlockTag that is called finalized.

var Web3 = require('web3');

async function main() {
    const blockNumberToCheck = 15625164;
    const web3 = new Web3("https://mainnet.infura.io/v3/<api-key>");
    const numberOfLatestFinalizedBlock = await web3.eth.getBlock("finalized");
    // console.log(numberOfLatestFinalizedBlock);
    if (blockNumberToCheck <= numberOfLatestFinalizedBlock.number) {
      console.log(`Block ${blockNumberToCheck} is Finalized`)
      return true
    } else {
      console.log(`Block ${blockNumberToCheck} is NOT Finalized`)
      return false
    }
  
  }
  
  // We recommend this pattern to be able to use async/await everywhere
  // and properly handle errors.
  main().catch((error) => {
    console.error(error);
    process.exitCode = 1;
  });
  

Answer 2

Just for reference to other people, if they are looking for cuRL requests, they can do it like so using Alchemy endpoints:

curl https://eth-mainnet.g.alchemy.com/v2/<apiKey> -k \
-X POST \
-H "Content-Type: application/json" \
-d '{"jsonrpc": "2.0", "method": "eth_getBlockByNumber", "params": ["finalized", false], "id": 0}' 

Answer 3

what about geth clique? i see "finalized" just on proof of stake butt on proof of authority is not found or im wrong configuration?

curl http://IP_ADDR:8545 \
  -X POST \
  -H "Content-Type: application/json" \
  --data '{"method":"eth_getBlockByNumber","params":["finalized",false],"id":1,"jsonrpc":"2.0"}' | jq

Output:

{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "code": -32000,
    "message": "finalized block not found"
  }
}