What is Swift Package Manager?
Swift Package Manager, often shortened to SwiftPM, is Apple's official tool for distributing Swift code and managing the dependencies an app relies on. You declare which packages you need, and it downloads the right versions, resolves conflicts, and compiles everything as part of the build. It is built directly into the Swift toolchain and into Xcode.
How Swift Package Manager works
A Swift package is a folder of source files plus a manifest named Package.swift. The manifest is written in Swift and describes the package: its name, the products it exposes, the targets that make up those products, and any other packages it depends on, each with a version rule such as "from 2.0.0". When you build, Swift Package Manager reads the manifest, fetches the dependency sources from their Git repositories, picks compatible versions, and compiles the whole graph. Because dependencies are plain Git repositories, there is no central server that must approve a package before you can use it.
Swift Package Manager and Xcode
In Xcode you add a dependency by pasting a package's repository URL into the project's package settings and choosing a version rule. Xcode resolves the package, downloads it, and links the chosen library products to your targets. The resolved versions are recorded in a Package.resolved file so that everyone building the project gets the same versions. This built in support is why many newer iOS projects use Swift Package Manager rather than a separate dependency tool, since nothing extra has to be installed.
Why it matters and how AppFlight uses it
Most modern iOS libraries publish a Swift package, so SwiftPM is the default way to pull in shared code for things like networking, analytics, or paywalls. AppFlight builds real native Swift and SwiftUI projects, and when an integration ships a Swift package, AppFlight can add it through Swift Package Manager so the dependency is wired into the build the same way an Xcode user would do it by hand.
FAQ
Is Swift Package Manager built into Xcode?
Yes. Xcode has Swift Package Manager support built in, so you can add a package by URL through the project settings without a separate command line tool. SwiftPM also works on its own through the swift command for projects that do not use Xcode.
What is the Package.swift file?
Package.swift is the package manifest. It is Swift code that declares the package name, its products and targets, and the other packages it depends on, including version rules. SwiftPM reads it to resolve and build everything.
Is Swift Package Manager free?
Yes. Swift Package Manager is open source and ships with the Swift toolchain. Packages themselves are usually hosted as public Git repositories, most commonly on GitHub.