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

# Supersim Multichain Development Environment

> Learn how to use the Supersim local dev environment tool designed to simulate the OP Stack multi-chain environment.

<Info>
  Interop is currently in active development and not yet ready for production use. The information provided here may change. Check back regularly for the most up-to-date information.
</Info>

[Supersim](https://github.com/ethereum-optimism/Supersim) is a local development environment tool designed to simulate the OP Stack for developers building multi-chain applications. It provides a simplified way to test and develop applications that interact with multiple chains within the OP Stack ecosystem.

## Supersim workflow

```mermaid theme={null}
graph LR
    A[Write Smart Contracts] --> B[Deploy on Supersim]
    B --> C[Test Cross-Chain Interactions]
    C --> D[Debug and Refine]
    D --> B
    C --> E[Ready for Production]
```

This diagram illustrates the typical workflow for developers using Supersim, from writing smart contracts to testing and refining cross-chain interactions.

## Features and benefits

* Simulates multiple OP Stack chains locally (e.g., chain 901, 902)
* Supports testing of cross-chain messaging and interactions
* Includes pre-deployed interoperability contracts
* Offers a CLI interface for starting and managing Supersim instances
* Provides local JSON-RPC endpoints for each simulated chain
* Allows for custom configuration of chain parameters
* Facilitates testing of Superchain-specific features like cross-chain token transfers
* Easy to use with common Ethereum development tools
* Supports chain forking

## Supersim CLI interaction

```mermaid theme={null}
graph TD
    A[Developer] --> B[Supersim CLI]
    B --> C[Chain 901]
    B --> D[Chain 902]
    B --> E[...]
    C --> F[JSON-RPC Endpoint]
    D --> G[JSON-RPC Endpoint]
    E --> H[JSON-RPC Endpoint]
```

This diagram illustrates how developers interact with Supersim through the CLI, which simulates OP Stack-specific features (specifically interop) on locally run chains, each with its own JSON-RPC endpoint and pre-deployed interoperability contracts.

## Next steps

* View more [Supersim tutorials](/app-developers/tutorials/development/supersim)