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

# Which Language To Use

> Smart contract development languages supported on Quai Network.

## Overview

Quai Network runs a modified Ethereum Virtual Machine environment that provides internal *and* cross-chain smart contract execution across zone chains in the network. Each chain's EVM is capable of executing smart contracts written in Solidity and other languages that compile to EVM bytecode.

<Warning>
  The Quai Network EVM supports Solidity versions up to
  [0.8.19](https://github.com/ethereum/solidity/releases/tag/v0.8.19). Using a
  newer version of Solidity may result in errors when deploying smart contracts.
</Warning>

## Choosing Which Language To Use

There are a few main differences between Solidity and SolidityX that developers should consider when choosing which language to use for smart contract development on Quai Network.

<Tip>
  For most developers and use cases, generic Solidity is the recommend smart
  contract language choice.
</Tip>

### Solidity

Generic Solidity is **recommended for most use cases and developers new to Quai Network**. It provides the most compatibility with existing Solidity and requires less initial configuration.

<CardGroup>
  <Card title="Single Chain" icon="link-horizontal-slash">
    Individual zone chain deployments **without cross-chain functionality**
  </Card>

  <Card title="Simple Setup" icon="sliders">
    Familiar configuration, deployment, and testing processes
  </Card>

  <Card title="Compatible Versions" icon="code-branch">
    Supports any previously existing Solidity compiler version **up to 0.8.19**
  </Card>

  <Card title="External Compatibility" icon="books">
    Compatible with existing contract libraries like
    [OpenZeppelin](https://www.openzeppelin.com/contracts) and
    [Solady](https://github.com/Vectorized/solady)
  </Card>
</CardGroup>

### SolidityX

SolidityX is **recommended for more advanced developers** looking to experiment with cross-chain functionality within Quai Network.

<CardGroup>
  <Card title="Cross-chain Deployment" icon="link-horizontal">
    Enables cross-chain contract deployments and sister contract linking
  </Card>

  <Card title="Advanced Setup" icon="gear-complex-code">
    Requires the [SolidityX
    compiler](https://github.com/dominant-strategies/SolidityX/releases/tag/0.8.19-solidityx)
    and additional configuration (can be more involved to set up)
  </Card>

  <Card title="Forward Compatibility" icon="forward">
    Will always be forward compatible with [dynamic scaling
    events](/learn/advanced-introduction/poem/sharding/dynamic-sharding)
  </Card>

  <Card title="Library Compatibility" icon="ban">
    Not compatible with pre-existing Solidity contract libraries.
  </Card>
</CardGroup>

* * * -{" "}