# What Swift Version Does FluidVoice Use?

> Discover the Swift version FluidVoice uses. altic-dev/FluidVoice requires Swift 5.9 as specified in its Package.swift file. Learn more now.

- Repository: [ALTIC/FluidVoice](https://github.com/altic-dev/FluidVoice)
- Tags: getting-started
- Published: 2026-07-08

---

**FluidVoice requires Swift 5.9**, as declared in the [`Package.swift`](https://github.com/altic-dev/FluidVoice/blob/main/Package.swift) manifest with the `// swift-tools-version: 5.9` directive.

FluidVoice is an open-source macOS application developed by altic-dev that leverages modern Swift language features. Understanding the **Swift version FluidVoice uses** is essential for contributors building the project locally or integrating its voice processing components.

## Where the Swift Version Is Declared

The required Swift version is explicitly set at the top of the package manifest:

```swift
// Package.swift – top of the file
// swift-tools-version: 5.9
import PackageDescription

let package = Package(
    name: "FluidVoice",
    platforms: [.macOS(.v15)],
    // ...
)

```

This **tools version declaration** instructs Swift Package Manager that the minimum Swift language version needed to compile the project is 5.9. According to the altic-dev/FluidVoice source code, this requirement ensures access to the latest language improvements and macOS 15 APIs.

## Platform Requirements and Compatibility

The Swift version directly dictates the supported platforms. FluidVoice targets **macOS 15**, which requires Swift 5.9 or later. This alignment ensures that the codebase can utilize modern concurrency features and enhanced generics capabilities introduced in Swift 5.9.

Attempting to build the project with Swift 5.8 or earlier will result in a tools version error, as SPM enforces this constraint before compilation begins.

## Code Examples and Project Structure

The Swift 5.9 requirement pervades the entire codebase. In [`Sources/Fluid/fluidApp.swift`](https://github.com/altic-dev/FluidVoice/blob/main/Sources/Fluid/fluidApp.swift), the entry point for the macOS app leverages Swift 5.9’s standard library. Similarly, [`Sources/Fluid/Views/RewriteModeView.swift`](https://github.com/altic-dev/FluidVoice/blob/main/Sources/Fluid/Views/RewriteModeView.swift) implements UI code that benefits from Swift 5.9 language improvements.

The test suite in [`Tests/FluidDictationIntegrationTests/DictationE2ETests.swift`](https://github.com/altic-dev/FluidVoice/blob/main/Tests/FluidDictationIntegrationTests/DictationE2ETests.swift) also requires Swift 5.9, ensuring consistency between the main application and its integration tests.

## Verifying the Swift Version Locally

To confirm your environment meets the requirements before building FluidVoice, run:

```bash
swift --version

```

The output should indicate **Swift 5.9** or newer. If you need to install a specific version, Xcode 15 includes Swift 5.9 by default, which aligns with the macOS 15 platform target specified in the package manifest.

## Summary

- **FluidVoice uses Swift 5.9** as its minimum required version, declared via `// swift-tools-version: 5.9` in [`Package.swift`](https://github.com/altic-dev/FluidVoice/blob/main/Package.swift).
- The project targets **macOS 15**, which necessitates Swift 5.9 compatibility according to the platform definitions.
- All source files, including [`Sources/Fluid/fluidApp.swift`](https://github.com/altic-dev/FluidVoice/blob/main/Sources/Fluid/fluidApp.swift) and [`Sources/Fluid/Views/RewriteModeView.swift`](https://github.com/altic-dev/FluidVoice/blob/main/Sources/Fluid/Views/RewriteModeView.swift), compile under this version.
- The test suite in [`Tests/FluidDictationIntegrationTests/DictationE2ETests.swift`](https://github.com/altic-dev/FluidVoice/blob/main/Tests/FluidDictationIntegrationTests/DictationE2ETests.swift) maintains the same Swift version requirements.

## Frequently Asked Questions

### Can I build FluidVoice with an older Swift version?

No. The `// swift-tools-version: 5.9` directive in [`Package.swift`](https://github.com/altic-dev/FluidVoice/blob/main/Package.swift) enforces a hard minimum. Swift Package Manager will reject attempts to build with Swift 5.8 or earlier, displaying a tools version error before compilation starts.

### Does FluidVoice work with Swift 6.0?

Yes. Swift 5.9 is the minimum requirement, not the maximum. You can build FluidVoice with Swift 6.0 or newer versions, as Swift maintains backward compatibility. The package manifest will accept any toolchain that meets or exceeds the 5.9 baseline.

### Why does FluidVoice require macOS 15?

The macOS 15 platform requirement in [`Package.swift`](https://github.com/altic-dev/FluidVoice/blob/main/Package.swift) correlates with the Swift 5.9 toolchain. This version alignment ensures access to the latest Apple SDK features and APIs that FluidVoice utilizes for its dictation and voice processing functionality.

### Where can I find the Swift version declaration in the repository?

The definitive declaration resides at the top of [`Package.swift`](https://github.com/altic-dev/FluidVoice/blob/main/Package.swift) in the repository root. The first line contains `// swift-tools-version: 5.9`, which serves as the canonical source for the project's Swift version requirements.