Monorepo with Swift: Code Organization for Beginners

Monorepo with Swift: Code Organization for Beginners

When you start developing applications in Swift for iOS or macOS, sooner or later you face the question: how to organize code so that it doesn't turn into chaos? Especially if you have several projects (for example, an iOS app, a watchOS extension, and a server-side part on Vapor). One modern approach is a monorepo. In this article, we will break down what a monorepo is, why it is needed in Swift development, and how to organize it in practice.

What is a monorepo and why is it needed?

A monorepo is an approach to code management where all projects, libraries, and modules are stored in a single repository (for example, in Git). Unlike multi-repositories, where each project lives in its own separate storage, a monorepo unifies everything in one place.

For Swift developers, this provides several advantages:

• Single version of dependencies — you know exactly which version of a library is used across all projects.
• Simplified refactoring — changing an API in one library is immediately visible in all dependent projects.
• Shared settings — one SwiftLint, one CI/CD config, one set of formatting rules.
• Easy search — everything is in one place, no need to switch between repositories.

However, there are nuances: a monorepo requires discipline and a proper structure, otherwise it turns into a "dump." But for beginners, this is an excellent way to learn how to organize code.

Monorepo structure for Swift projects

Suppose you are creating an iOS app with shared modules. A typical monorepo structure in Swift might look like this:

MyMonorepo/├── Apps/│   ├── iOSApp/          # Main iOS application│   │   ├── Sources/│   │   ├── Resources/│   │   └── Package.swift│   └── macOSApp/        # macOS version│       ├── Sources/│       └── Package.swift├── Packages/│   ├── Core/            # Common utilities (networking, logging)│   │   ├── Sources/│   │   └── Package.swift│   ├── UIComponents/    # Reusable UI components│   │   ├── Sources/│   │   └── Package.swift│   └── Analytics/       # Analytics module│       ├── Sources/│       └── Package.swift├── Scripts/             # Helper scripts├── .swiftlint.yml       # Unified linter config├── Package.swift        # Root manifest (optional)└── README.md

Note: here we use Swift Package Manager (SPM) — the standard tool for managing dependencies in Swift. Each module is a separate Swift Package that can be connected to applications.

How to create a monorepo in Swift: step-by-step guide

Let's create a simple monorepo with two modules and one application. Follow these steps in the terminal:

Step 1: Create the root directory and initialize Git

mkdir MyMonorepocd MyMonorepogit init

Step 2: Create the folder structure

mkdir -p Apps/iOSApp/Sourcesmkdir -p Packages/Core/Sourcesmkdir -p Packages/UIComponents/Sources

Step 3: Create Package.swift for the Core module

Create the file Packages/Core/Package.swift:

// swift-tools-version:5.9import PackageDescription

let package = Package(    name: "Core",    platforms: [        .iOS(.v16),        .macOS(.v13)    ],    products: [        .library(            name: "Core",            targets: ["Core"])    ],    targets: [        .target(            name: "Core",            path: "Sources")    ])

Step 4: Write simple code in the Core module

Create Packages/Core/Source