> ## Documentation Index
> Fetch the complete documentation index at: https://docs.magicblock.gg/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Automated, time-based execution of on-chain instructions

## What Are Cranks?

Cranks (scheduled tasks) enable **automated, time-based execution** of on-chain instructions without requiring manual user intervention. In traditional blockchain systems, every action requires a user to sign and submit a transaction, which limits automation capabilities.

With MagicBlock's Ephemeral Rollups, you can schedule tasks that execute automatically at predetermined intervals, bringing powerful automation capabilities to your Solana programs.

## Key Benefits

* **Automated Execution**: Programs can execute instructions at predetermined intervals without user interaction
* **Cost Efficiency**: Reduces the need for off-chain cron jobs or monitoring services
* **Decentralization**: Execution happens on-chain, maintaining trustless guarantees
* **Reliability**: Scheduled tasks execute reliably within the blockchain's consensus mechanism

## Use Cases

* **Periodic State Updates**: Update prices, clear expired data, or refresh game state
* **Automated Workflows**: Recurring payments, vesting schedules, or subscription renewals
* **Game Mechanics**: Periodic rewards, time-based events, or automated game progression
* **DeFi Operations**: Rebalancing portfolios, liquidation checks, or yield compounding

<CardGroup cols={2}>
  <Card title="Implementation" icon="code" href="/pages/tools/crank/implementation" iconType="duotone">
    Learn how to implement cranks in your program
  </Card>

  <Card title="Code Example" icon="github" href="https://github.com/magicblock-labs/magicblock-engine-examples/tree/main/crank-counter" iconType="duotone">
    Check out our GitHub repository
  </Card>
</CardGroup>

## How It Works

Cranks leverage MagicBlock's Ephemeral Rollups to provide scheduled execution:

1. **Initialize** your program state on Solana base layer
2. **Delegate** accounts to Ephemeral Rollup for faster execution
3. **Schedule** a crank task that automatically executes instructions
4. **Execute** automatically at specified intervals
5. **Undelegate** accounts back to Solana base layer when done

The scheduling happens through Cross-Program Invocation (CPI) to MagicBlock's scheduling program, which handles the actual execution timing and reliability.

<Callout type="info">
  Cranks execute within the Ephemeral Rollup's consensus mechanism, ensuring reliable and trustless execution. For detailed implementation steps, see the <a href="/pages/tools/crank/implementation">Implementation</a> guide.
</Callout>