---
title: Set Custom Gas Limits
description: How to set custom gas limits for Entropy callbacks
---

# Set Custom Gas Limits

By default, Pyth Entropy uses a predefined gas limit for callback functions. However, you may need to adjust this limit based on the complexity of your callback implementation.

## When to Use Custom Gas Limits

### Use Higher Gas Limits When:

- Your callback function performs complex calculations
- You need to update multiple storage variables
- Your callback interacts with other contracts
- You're implementing complex game logic

### Use Lower Gas Limits When:

- Your callback function is simple (e.g., just stores a single value)
- You want to optimize for cost
- You want to prevent potential gas griefing

## Implementation

### Using EntropyV2 Interface

```solidity
import "@pythnetwork/entropy-sdk-solidity/IEntropyV2.sol";

contract MyContract is IEntropyConsumer {
    IEntropyV2 entropy;

    function requestWithCustomGas() external payable {
        uint32 customGasLimit = 200000; // Adjust based on your needs

        // Get fee for custom gas limit
        uint256 fee = entropy.getFeeV2(customGasLimit);
        require(msg.value >= fee, "Insufficient fee");

        // Request with custom gas limit
        uint64 sequenceNumber = entropy.requestV2{value: fee}(customGasLimit);
    }
}
```

### Full Control Request

```solidity
function requestWithFullControl() external payable {
    address provider = entropy.getDefaultProvider();
    uint32 gasLimit = 150000;
    bytes32 userRandomNumber = keccak256(abi.encode(block.timestamp, msg.sender));

    uint256 fee = entropy.getFeeV2(provider, gasLimit);
    require(msg.value >= fee, "Insufficient fee");

    uint64 sequenceNumber = entropy.requestV2{value: fee}(
        provider,
        gasLimit,
        userRandomNumber
    );
}
```

## Gas Limit Constraints

Each network has different gas limit constraints:

| Network   | Min Gas Limit | Max Gas Limit | Default |
| --------- | ------------- | ------------- | ------- |
| Ethereum  | 50,000        | 100,000       | 100,000 |
| Arbitrum  | 50,000        | 100,000       | 100,000 |
| Avalanche | 50,000        | 100,000       | 100,000 |
| Base      | 50,000        | 100,000       | 100,000 |
| BNB Chain | 50,000        | 100,000       | 100,000 |
| Optimism  | 50,000        | 100,000       | 100,000 |
| Polygon   | 50,000        | 100,000       | 100,000 |

## Best Practices

1. **Test your callback function** to estimate gas usage before setting custom limits
2. **Add a buffer** of 10-20% to your estimated gas usage for safety
3. **Use the minimum necessary** gas limit to reduce costs
4. **Consider network differences** - some networks may have different gas costs for similar operations