40 Free Xcode Playgrounds From 3DaysOfSwift.com
- Nov 24, 2025
- 5 min read
40 Free Xcode Playgrounds From 3DaysOfSwift.com
One of the most frustrating parts of preparing for an iOS interview is realising that understanding Swift and remembering Swift are not the same thing.
Most professional developers have already learned the majority of the concepts they are likely to encounter during an interview. They have read documentation, watched conference sessions, worked through tutorials, and spent years writing production code. Yet many developers still experience the same problem when an interview approaches. Topics that once felt completely familiar suddenly become difficult to explain with confidence.
A developer may have used protocols for years but struggle to clearly discuss protocol composition. Another may understand concurrency conceptually but find it difficult to explain actors and actor isolation under interview pressure. Someone else may remember learning ARC in detail yet realise they have not thought about retain cycles for months.
These situations are extremely common because software development naturally pushes attention toward whatever problem is currently being solved. Knowledge that is not revisited regularly becomes harder to access even when it has not truly been forgotten.
This observation became one of the main reasons 3DaysOfSwift was created.
Why Traditional Learning Resources Are Not Always Enough
The Swift community already provides excellent educational material. Apple's official Swift language book remains one of the strongest programming language references available today. Apple's SwiftUI tutorials provide a practical introduction to building applications across the Apple ecosystem, while WWDC sessions offer direct insight from the engineers building the tools developers use every day.
Useful resources include:
The challenge is that most educational resources are designed around learning something for the first time. They follow a structured path from beginner topics toward more advanced material. This works exceptionally well when a developer is new to Swift, but it becomes less efficient when the goal is revision.
An experienced iOS developer preparing for an interview next week rarely wants to restart an entire Swift course from chapter one. More often, they want a practical way to revisit specific topics such as ARC, closures, generics, concurrency, protocols, value semantics, or architecture principles. They are not trying to learn everything again. They are trying to strengthen knowledge that already exists.
Revision Is A Different Skill From Learning
One of the biggest misconceptions in software development is the belief that learning something once should be enough.
In reality, most professional skills require revision. Pilots revise procedures. Athletes revisit fundamentals. Musicians practise scales they learned years earlier. Software development is no different, particularly because the volume of technical knowledge developers are expected to maintain continues to increase every year.
A modern iOS developer may be expected to understand Swift language fundamentals, SwiftUI, UIKit, concurrency, testing, architecture, dependency injection, networking, accessibility, persistence, memory management, and a growing collection of Apple frameworks. No developer actively uses every one of these topics every week.
As a result, recall naturally weakens in areas that are not being exercised regularly. This becomes especially noticeable during technical interviews because interviewers often explore language features that may not have appeared recently in a candidate's day to day work.
The solution is not necessarily more learning.
Often the solution is better revision.
Why Xcode Playgrounds Work So Well
One of the reasons Xcode playgrounds are particularly effective for revision is that they remove much of the friction that normally surrounds experimentation.
Suppose a developer wants to revisit ARC. Creating a full application project introduces navigation, user interfaces, application structure, and many other concerns that are unrelated to memory management. The same problem appears when revisiting generics, protocols, actors, closures, or value semantics. The developer often spends more time creating an environment than actually exploring the concept.
A playground solves this problem by reducing the distance between curiosity and experimentation. The developer can open a file, run code immediately, modify examples, test assumptions, and observe behaviour without the overhead of constructing an entire application.
This shorter feedback loop encourages exploration. More importantly, it keeps attention focused on the Swift language feature being studied rather than the surrounding infrastructure.
What Is Included In The 3DaysOfSwift Collection
Today, 3DaysOfSwift provides a large collection of downloadable Swift resources designed specifically for revision, experimentation, and interview preparation. According to the platform, the collection currently includes over 40 downloadable Xcode playgrounds and resources covering many of the language features and concepts discussed throughout modern Swift development.
Topics explored throughout the collection include:
Optionals
Protocols
Extensions
Closures
ARC
Generics
Property Wrappers
Concurrency
Actors
Opaque Types
Existential Types
Value and Reference Semantics
SwiftUI Architecture
Grand Central Dispatch
Protocol Extensions
Technical Interview Questions
The platform also includes playgrounds inspired by the official Swift language book alongside practical interview focused material designed to strengthen understanding of commonly discussed Swift concepts.
Rather than presenting concepts as static notes, the playgrounds encourage developers to interact directly with the language. Developers can execute code, modify examples, investigate behaviour, and strengthen understanding through practical experimentation.
Built For Developers Preparing For Interviews
One theme appears repeatedly throughout the 3DaysOfSwift platform.
Interview preparation.
The website openly focuses on helping developers revisit important Swift concepts before technical interviews and strengthen areas that may have become rusty over time. Topics such as ARC, concurrency, protocols, architecture, optionals, and memory management receive particular attention because they appear frequently during interview discussions.
This focus reflects a practical reality of modern hiring. Many companies evaluate not only whether a developer has used Swift, but how deeply they understand it. Candidates are often expected to explain language behaviour, discuss design decisions, and reason about concepts rather than simply write framework code.
Developers who regularly revisit these topics tend to perform more confidently because the knowledge remains easier to access when needed.
Why Everything Is Free
One aspect of the platform that stands out is the decision to make the playground collection freely available.
Many educational platforms reserve their most useful resources for paid memberships or subscriptions. While there is nothing inherently wrong with paid education, 3DaysOfSwift has chosen to make its playground collection openly accessible so that developers can download resources and begin revising immediately. The website explicitly positions the playgrounds as free interview preparation resources designed to help developers strengthen their Swift fundamentals.
Removing barriers matters because revision works best when it is easy to begin. If a developer decides they want to revisit concurrency, protocols, or ARC, the ideal outcome is that they can immediately open a playground and start experimenting rather than spending time navigating paywalls, subscriptions, or lengthy onboarding processes.
Explore The Collection
Developers interested in strengthening their Swift fundamentals, revisiting language features, or preparing for technical interviews can explore the collection here:
The platform continues to focus on a simple idea that is often overlooked throughout technical education. Learning Swift is important, but retaining Swift is equally important. A developer who regularly revisits important concepts generally finds it much easier to explain them, apply them, and discuss them confidently when opportunities arise.
The goal is not to start learning from the beginning every time knowledge becomes rusty.
The goal is to create practical opportunities to revisit concepts before they fade too far from memory. Through downloadable Xcode playgrounds focused on experimentation and revision, 3DaysOfSwift aims to make that process significantly easier.
Good luck.
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