getSlotLeaders - Solana

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

This method returns the identity Pubkey of the scheduled leader for each slot in a contiguous range. A maximum of 5,000 slots can be requested per call.

Parameters

Parameter	Type	Required	Description
startSlot	number	Yes	First slot of the range, inclusive
limit	number	Yes	Number of slots to return, between 1 and 5000

Request

cURL

curl --location --request POST 'https://go.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "getSlotLeaders",
    "params": [397234561, 4],
    "id": "getblock.io"
}'

@solana/web3.js

example.js

const { Connection } = require('@solana/web3.js');

const connection = new Connection('https://go.getblock.io/<ACCESS-TOKEN>/', 'confirmed');

const leaders = await connection.getSlotLeaders(397234561, 4);

console.log(leaders.map((l) => l.toBase58()));

Request

example.py

import requests

response = requests.post(
    'https://go.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'getSlotLeaders',
        'params': [397234561, 4],
        'id': 'getblock.io'
    }
)

print(response.json()['result'])

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": "getSlotLeaders",
            "params": [397234561, 4],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;

    println!("Result: {}", response["result"]);
    Ok(())
}

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": [
        "dv1ZAGvdsz5hHLwWXsVnM94hWf1pjbKVau1QVkaMJ92",
        "dv1ZAGvdsz5hHLwWXsVnM94hWf1pjbKVau1QVkaMJ92",
        "dv1ZAGvdsz5hHLwWXsVnM94hWf1pjbKVau1QVkaMJ92",
        "dv1ZAGvdsz5hHLwWXsVnM94hWf1pjbKVau1QVkaMJ92"
    ]
}

Response Parameters

Parameter	Type	Description
jsonrpc	string	JSON-RPC protocol version ("2.0")
id	string	Request identifier matching the request
result	array	Array of leader identity Pubkeys, one per slot in the requested range

Use Cases

• Leader Prefetch: Warm connections to the next few leaders before sending

• Send Fanout: Broadcast a transaction to several upcoming leaders at once

• Rotation Analysis: Observe the four-slot leader rotation pattern directly

• Operator Alerts: Notify an operator shortly before its leader slots begin

Error Handling

Error Code	Message	Description
-32602	Invalid params	Limit exceeds 5000 or the range extends beyond the known schedule
-32603	Internal error	Node failed to read the leader schedule for the range
-32005	Node is unhealthy	The node has fallen behind the cluster tip