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

# Best Practices

> Learn the best practices for building smart contracts on Abstract.

This page outlines the best practices to follow in order to best utilize Abstract's
features and optimize your smart contracts for deployment on Abstract.

## Do not rely on EVM gas logic

Abstract has different gas logic than Ethereum, mainly:

1. The price for transaction execution fluctuates as it depends on the price of L1 gas price.
2. The price for opcode execution is different on Abstract than Ethereum.

### Use `call` instead of `.send` or `.transfer`

Each opcode in the EVM has an associated gas cost. The `send` and `transfer` functions have a `2300` gas stipend.

If the address you call is a smart contract (which all accounts on Abstract are),
the recipient contract may have some custom logic that requires more than 2300 gas to execute upon receiving the funds,
causing the call to fail.

For this reason, it is strongly recommended to use `call` instead of `.send` or `.transfer` when sending funds to a smart contract.

```solidity theme={null}
// Before:
payable(addr).send(x)
payable(addr).transfer(x)

// After:
(bool success, ) = addr.call{value: x}("");
require(success, "Transfer failed.");
```

**Important:** Using `call` does not
provide the same level of protection against [reentrancy attacks](https://blog.openzeppelin.com/reentrancy-after-istanbul).
Some additional changes may be required in your contract. [Learn more in this security report ↗](https://consensys.io/diligence/blog/2019/09/stop-using-soliditys-transfer-now/).

### Consider `gasPerPubdataByte`

[EIP-712](https://eips.ethereum.org/EIPS/eip-712) transactions have a `gasPerPubdataByte`
field that can be set to control the amount of gas that is charged for each byte of data sent to L1
(see [transaction lifecycle](/how-abstract-works/architecture/transaction-lifecycle)). \[Learn more ↗]\([https://docs.zksync.io/zksync-protocol/rollup/fee-model/how-we-charge-for-pubdata](https://docs.zksync.io/zksync-protocol/rollup/fee-model/how-we-charge-for-pubdata).

When calculating how much gas is remaining using `gasleft()`, consider that the
`gasPerPubdataByte` also needs to be accounted for.

While the [system contracts](/how-abstract-works/system-contracts/overview)
currently have control over this value, this may become decentralized
in the future; therefore it’s important to consider that the
operator can choose any value up to the upper bound submitted in the signed transaction.

## Address recovery with `ecrecover`

Review the recommendations in the [signature validation](/how-abstract-works/native-account-abstraction/signature-validation)
section when recovering the address from a signature, as the sender of a transaction may not use [ECDSA](https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm)
(i.e. it is not an EOA).