> ## Documentation Index
> Fetch the complete documentation index at: https://www.helius.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# How to Use getLeaderSchedule
> Learn getLeaderSchedule use cases, code examples, request parameters, response structure, and tips.
The [`getLeaderSchedule`](https://www.helius.dev/docs/api-reference/rpc/http/getleaderschedule) RPC method returns the assignment of block production leadership to validators for a specific epoch. Understanding the leader schedule can be useful for network analysis, predicting which validator will produce blocks at certain times, or for tools that interact with specific leaders.
## Common Use Cases
* **Network Monitoring:** Observe the distribution of leader slots among validators in an epoch.
* **Transaction Routing (Advanced):** Some advanced applications might try to route transactions to the current or upcoming leader, though this is generally handled by the network and RPC nodes.
* **Validator Performance Analysis:** Correlate the leader schedule with actual block production to assess validator uptime and performance.
* **Understanding Epoch Progression:** See which validators are responsible for producing blocks throughout an epoch.
## Request Parameters
The method can take up to two optional parameters:
1. **`slot`** (u64, optional): A slot number. If provided, the leader schedule for the epoch containing this slot will be fetched. If `null` or omitted, the leader schedule for the current epoch is fetched.
2. **`config`** (object, optional): A configuration object that can contain:
* **`commitment`** (string, optional): Specifies the [commitment level](https://www.helius.dev/blog/solana-commitment-levels). If not provided, the node's default commitment is used.
* **`identity`** (string, optional): A base-58 encoded public key of a validator. If provided, the returned schedule will only include slots assigned to this specific validator.
## Response Structure
The `result` field of the JSON-RPC response will be:
* `null`: If the epoch corresponding to the requested `slot` (or current epoch if no slot is provided) is not found or its leader schedule is not available (e.g., for a future, uncalculated epoch).
* An **object**: If a schedule is found. This object is a map where:
* Each **key** is the base-58 encoded public key (identity) of a validator.
* The corresponding **value** is an array of numbers. Each number is a slot index *relative to the start of the epoch* for which that validator is the leader.
For example, if an epoch starts at slot `1000` and a validator has `[0, 1, 5]` in its schedule, it means that validator is the leader for slots `1000`, `1001`, and `1005`.
## Examples
### 1. Get Leader Schedule for the Current Epoch
This example fetches the complete leader schedule for the current epoch.
```bash cURL theme={"system"}
# Replace with your Helius API key
curl https://mainnet.helius-rpc.com/?api-key= -X POST -H "Content-Type: application/json" -d \
'{
"jsonrpc": "2.0",
"id": 1,
"method": "getLeaderSchedule"
}'
```
```javascript JavaScript (using @solana/web3.js) theme={"system"}
// Replace with your Helius API key
const { Connection } = require('@solana/web3.js');
async function fetchCurrentLeaderSchedule() {
const connection = new Connection('https://mainnet.helius-rpc.com/?api-key=');
try {
const leaderSchedule = await connection.getLeaderSchedule(); // Fetches for current epoch by default
if (leaderSchedule) {
console.log('Leader Schedule for Current Epoch:');
for (const [validatorIdentity, slots] of Object.entries(leaderSchedule)) {
console.log(` Validator: ${validatorIdentity}`);
console.log(` Slots (relative to epoch start): ${slots.join(', ')}`);
}
} else {
console.log('Leader schedule for the current epoch not found or not yet available.');
}
// console.log(JSON.stringify(leaderSchedule, null, 2));
} catch (error) {
console.error('Error fetching leader schedule:', error);
}
}
fetchCurrentLeaderSchedule();
```
### 2. Get Leader Schedule for a Specific Validator in a Specific Epoch (by Slot)
This example fetches the leader schedule for a given validator identity for the epoch containing slot `200000`.
```bash cURL theme={"system"}
# Replace with your Helius API key
# Replace VALIDATOR_PUBKEY with an actual validator identity public key
curl https://mainnet.helius-rpc.com/?api-key= -X POST -H "Content-Type: application/json" -d \
'{
"jsonrpc": "2.0",
"id": 1,
"method": "getLeaderSchedule",
"params": [
200000,
{ "identity": "VALIDATOR_PUBKEY" }
]
}'
```
```javascript JavaScript (using @solana/web3.js) theme={"system"}
// Replace with your Helius API key
// Replace VALIDATOR_PUBKEY with an actual validator identity public key
const { Connection, PublicKey } = require('@solana/web3.js');
async function fetchValidatorEpochSchedule() {
const connection = new Connection('https://mainnet.helius-rpc.com/?api-key=');
const targetSlot = 200000;
const validatorIdentity = 'VALIDATOR_PUBKEY'; // e.g., 'Vote111111111111111111111111111111111111111'
try {
const leaderSchedule = await connection.getLeaderSchedule(targetSlot, { identity: validatorIdentity });
if (leaderSchedule && leaderSchedule[validatorIdentity]) {
console.log(`Leader Schedule for Validator ${validatorIdentity} in epoch of slot ${targetSlot}:`);
console.log(` Slots (relative to epoch start): ${leaderSchedule[validatorIdentity].join(', ')}`);
} else {
console.log(`No leader slots found for validator ${validatorIdentity} in epoch of slot ${targetSlot}, or schedule not available.`);
}
// console.log(JSON.stringify(leaderSchedule, null, 2));
} catch (error) {
console.error('Error fetching validator leader schedule:', error);
}
}
fetchValidatorEpochSchedule();
```
## Developer Tips
* **Epoch Boundaries:** The leader schedule is fixed for an entire epoch. You can use `getEpochInfo` to find the start and end slots of an epoch.
* **Future Epochs:** Requesting the schedule for an epoch far in the future might return `null` if the network hasn't calculated it yet.
* **Relative Slot Indices:** Remember that the slot numbers in the response are relative to the first slot of the *requested* epoch, not absolute slot numbers on the blockchain.
* **Large Response:** For a full epoch schedule without an identity filter, the response can be large, listing all validators and their assigned slots.
This guide provides the necessary information to use `getLeaderSchedule` to query block producer assignments for any given epoch on the Solana network.
## Related Methods
Get current epoch information including slot boundaries
Get leaders for a specific range of slots