GetLatestBlockhash

Returns the latest blockhash and the last valid block height for transaction signing.

Type: unary

Overview

GetLatestBlockhash retrieves the most recent blockhash from the cluster along with the last valid block height. This is essential for constructing and signing transactions, as Solana transactions require a recent blockhash to be considered valid.

For HFT and MEV applications, having a fresh blockhash with minimal latency is critical. Using a stale blockhash will result in transaction failures. This gRPC method provides faster access compared to the equivalent JSON-RPC call.

Parameters

Name	Type	Description
commitment	CommitmentLevel	Optional. The commitment level: processed, confirmed, or finalized.

Response

Field	Type	Description
blockhash	string	The latest blockhash as a base-58 encoded string
last_valid_block_height	uint64	The last block height at which the blockhash will be valid
slot	uint64	The slot in which the blockhash was produced

Usage Examples

Node.js

1const grpc = require('@grpc/grpc-js');
2const protoLoader = require('@grpc/proto-loader');
3
4const packageDef = protoLoader.loadSync('geyser.proto', {
5  keepCase: true, longs: String, enums: String, defaults: true, oneofs: true
6});
7const proto = grpc.loadPackageDefinition(packageDef).geyser;
8const client = new proto.Geyser('[IP_ADDRESS]:[PORT]', grpc.credentials.createInsecure());
9
10client.getLatestBlockhash({}, (err, response) => {
11  if (err) { console.error(err); return; }
12  console.log('Response:', response);
13});

Rust

1use yellowstone_grpc_proto::geyser::geyser_client::GeyserClient;
2use tonic::transport::Channel;
3
4#[tokio::main]
5async fn main() -> Result<(), Box<dyn std::error::Error>> {
6    let channel = Channel::from_static("http://[IP_ADDRESS]:[PORT]")
7        .connect().await?;
8    let mut client = GeyserClient::new(channel);
9
10    let response = client.getLatestBlockhash(tonic::Request::new(())).await?;
11    println!("Response: {:?}", response.into_inner());
12
13    Ok(())
14}