## Building contracts

Forge compiles all Solidity files in your `src/` directory and outputs artifacts to `out/`.

:::terminal
```bash
// [!include ~/snippets/output/hello_foundry/forge-build:command]
```

```ansi
// [!include ~/snippets/output/hello_foundry/forge-build:output]
```
:::

### Compiler versions

Forge auto-detects the required Solidity version from your contracts' pragma statements and downloads the compiler automatically.

To pin a specific version:

```toml [foundry.toml]
[profile.default]
solc_version = "0.8.28"
```

Or use a version range:

```toml [foundry.toml]
[profile.default]
solc = ">=0.8.0 <0.9.0"
```

### Optimization

Enable the optimizer for production deployments:

```toml [foundry.toml]
[profile.default]
optimizer = true
optimizer_runs = 200
```

Higher `optimizer_runs` values optimize for frequent function calls at the cost of larger bytecode. Use lower values (like `1`) for contracts deployed once and rarely called.

For maximum optimization with via-IR:

```toml [foundry.toml]
[profile.default]
optimizer = true
optimizer_runs = 200
via_ir = true
```

:::warning
via-IR compilation is slower but can produce more optimized bytecode. Enable it only when needed.
:::

### Build profiles

Define separate profiles for development and production:

```toml [foundry.toml]
[profile.default]
optimizer = false

[profile.production]
optimizer = true
optimizer_runs = 200
via_ir = true
```

Build with a specific profile:

```bash
$ FOUNDRY_PROFILE=production forge build
```

### Inspecting artifacts

View contract ABI:

```bash
$ forge inspect Counter abi
```

View deployed bytecode:

```bash
$ forge inspect Counter bytecode
```

View storage layout:

```bash
$ forge inspect Counter storage-layout
```

View all available fields:

```bash
$ forge inspect Counter --help
```

### Build cache

Forge caches compilation results. To force a full rebuild:

```bash
$ forge build --force
```

Clear the cache entirely:

```bash
$ forge clean
```

### Watching for changes

Rebuild automatically when files change:

```bash
$ forge build --watch
```