getblockhash - Zcash

Example code for the getblockhash JSON-RPC method. Сomplete guide on how to use the getblockhash JSON-RPC method in GetBlock.io Web3 documentation.

This method returns the block hash at a given height. Used by indexers iterating through historical blocks and by explorers resolving user-supplied height inputs to hashes.

Parameters

Parameter	Type	Required	Description
height	integer	Yes	Block height (0 or greater)

Request

cURL

curl --location --request POST 'https://go.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "getblockhash",
    "params": [
        2856342
    ],
    "id": "getblock.io"
}'

Axios

example.js

const axios = require('axios');

const response = await axios.post('https://go.getblock.io/<ACCESS-TOKEN>/', {
    jsonrpc: '2.0',
    method: 'getblockhash',
    params: [
        2856342
    ],
    id: 'getblock.io'
}, {
    headers: { 'Content-Type': 'application/json' }
});

console.log(response.data.result);

Request

example.py

import requests

response = requests.post(
    'https://go.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'getblockhash',
        'params': [
            2856342
        ],
        'id': 'getblock.io'
    }
)

print(response.json())

Rust

example.rs

use reqwest::Client;
use serde_json::{json, Value};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = Client::new();
    
    let response = client
        .post("https://go.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&json!({
            "jsonrpc": "2.0",
            "method": "getblockhash",
            "params": [
                2856342
            ],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;
    
    println!("Result: {}", response["result"]);
    Ok(())
}

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "00000000018bb43cadf5b4c8a2e7f9d0e1a6b3c8d5e4f2a1b0c9d8e7f6a5b4c3"
}

Response Parameters

Parameter	Type	Description
result	string	Hex-encoded 32-byte block hash at the requested height

Use Cases

• Height-to-Hash Resolution: Convert a user-supplied block height into a hash for subsequent detail queries

• Historical Backfill: Iterate heights 0..tip to enumerate the full chain by hash

• Explorer Search: Resolve numeric block searches to hashes for the detail view

Error Handling

Error Code	Message	Description
-8	Block height out of range	Requested height exceeds the current chain tip
-32602	Invalid params	Height parameter is malformed or negative
-32603	Internal error	Node failed to look up the block