---
description: Chisel is Foundry's interactive Solidity REPL for rapid prototyping and debugging.
---

## Chisel

Chisel is an interactive Solidity REPL (Read-Eval-Print Loop) for rapid prototyping and debugging. Write and execute Solidity code instantly without compiling full contracts.

When run inside a Foundry project, Chisel uses that project's configuration and dependencies.

### Key capabilities

| Feature | Description |
|---------|-------------|
| **Interactive execution** | Execute Solidity expressions and statements in real-time |
| **Variable inspection** | Inspect values, types, and raw stack/memory data |
| **Forking** | Fork any chain to interact with live contracts |
| **Session management** | Save, load, and export REPL sessions |
| **Project integration** | Access your project's contracts and dependencies |

### Common workflows

```bash [Start the REPL]
$ chisel
```

```bash [Fork mainnet]
$ chisel --fork-url https://ethereum.reth.rs/rpc
```

```bash [Evaluate without entering REPL]
$ chisel eval "uint256 x = 1 + 2; x"
```

```bash [Load a saved session]
$ chisel load my-session
```

```bash [List cached sessions]
$ chisel list
```

### Quick example

```solidity
➜ uint256 x = 10
➜ uint256 y = 20
➜ x + y
Type: uint256
├ Hex: 0x1e
├ Hex (full word): 0x1e
└ Decimal: 30
```

### Learn more

- [Session management](/chisel/session-management) — Save, load, and export sessions
- [Forking](/chisel/forking) — Interact with live chain state
- [Commands](/chisel/commands) — All available REPL commands
- [Reference](/reference/chisel/chisel) — Full CLI reference
