John Sundell

@johnsundell
6.8K Followers
52 Following
284 Posts
Swift and Rust developer. Creator of Swift by Sundell, and co-host of the Stacktrace podcast.
Websitehttps://swiftbysundell.com
Stacktracehttps://stacktracepodcast.fm
GitHubhttps://github.com/johnsundell
Workshopshttps://www.mobileworkshops.io
John SundellMay 13

This month's Stacktrace episode is a classic deep-dive episode - this time about building cross-platform UI frameworks and macOS virtualization, had so much fun recording it! 😀

https://stacktracepodcast.fm/episodes/207

207: “It’s not magic, it’s all in the kernel” | Stacktrace

John builds a cross-platform UI framework in Rust, and Rambo uses the macOS virtualization system to create a virtual iPhone.

Stacktrace
John SundellApr 8

This month's episode of the Stacktrace podcast is out! 😀 On this episode, @_inside and I talk about Android and the state of Swift Package Manager 🤖📦

https://stacktracepodcast.fm/episodes/206

206: “Let’s deprecate Xcode projects” | Stacktrace

Using Android as an iOS user, and the state of Swift Package Manager, including how it could become a more full-featured orchestration tool for Xcode projects.

Stacktrace
John SundellMar 11

Super excited to bring back the Stacktrace podcast (again!), with monthly episodes starting... right now! 😀

https://stacktracepodcast.fm/episodes/205

205: “The 2026 edition” | Stacktrace

On this first episode of the 2026 season, John and Rambo discuss how they’re using AI agents when working on different projects, and how to approach learning new programming languages in 2026.

Stacktrace
John SundellAug 31, 2025
Just published a new article on a Sunday, like the good old days when I used to write weekly Swift articles 😀 This one is about getting started building a design system for an iOS app: https://www.swiftbysundell.com/articles/building-a-design-system-at-genius-scan
Building a design system at Genius Scan | Swift by Sundell

An example of how to approach the task of building a design system for an app, by focusing on creating an initial set of reusable components that can be tweaked using the SwiftUI environment.

Swift by Sundell
John SundellJul 23, 2025

New article about deciding whether to use 'let' or 'var' when declaring Swift struct properties! 😀

https://www.swiftbysundell.com/articles/let-vs-var-for-swift-struct-properties

Deciding between ‘let’ and ‘var’ for Swift struct properties | Swift by Sundell

Does marking a given Swift struct property as either ‘let’ or ‘var’ simply determine its mutability, or is there more to it? Let’s explore!

Swift by Sundell
John SundellJun 30, 2025
New article about a bit of a hidden gem within Swift's built-in Codable API - CodableWithConfiguration, which is super useful when we need to decode a type which requires additional data not present in the JSON (or whichever other data we're decoding from): https://www.swiftbysundell.com/articles/decoding-swift-types-that-require-additional-data
Decoding Swift types that require additional data | Swift by Sundell

How Swift’s CodableWithConfiguration API can be used to inject additional, required data into a type’s decoding process, without having to use optionals or declare any additional decoding-specific types.

Swift by Sundell
John SundellMay 30, 2025

It's time for a new article! 😀 This time, I'm sharing some tips and tricks for when using SwiftUI's ViewBuilder to create custom container views. Hope you'll enjoy it, and happy Friday!

https://www.swiftbysundell.com/articles/swiftui-viewbuilder-tips-and-tricks

Tips and tricks for when using SwiftUI’s ViewBuilder | Swift by Sundell

Let’s explore how we can use SwiftUI’s ViewBuilder within our own code, and a few things that can be good to keep in mind when doing so.

Swift by Sundell
John SundellApr 15, 2025

This time, it took me just two weeks (instead of two years 😅) to publish another new article!

Here's "Using Swift's defer keyword within async and throwing contexts", hope you'll find it useful 👍

https://www.swiftbysundell.com/articles/using-defer-within-async-and-throwing-contexts

Using Swift’s defer keyword within async and throwing contexts | Swift by Sundell

How Swift’s defer keyword can be incredibly useful when working with code scopes that have multiple exit points, such as throwing or async functions.

Swift by Sundell
John SundellApr 1, 2025

Yesterday, I didn't just announce that Swift by Sundell is back (🎉), but I also published the first new article on the website in two years - about modern URL construction using the latest Foundation APIs and a custom extension/macro!

Hope you'll enjoy it 😀

https://www.swiftbysundell.com/articles/modern-url-construction-in-swift

Modern URL construction in Swift | Swift by Sundell

How to combine Foundation’s latest URL APIs with Swift features like macros, to be able to work with both static and dynamic URLs in simpler and more predictable ways.

Swift by Sundell
John SundellMar 31, 2025
The Grizzly LabsMar 31, 2025

We're particularly excited to enable @johnsundell to bring back Swift by Sundell! This is one of the most valuable resources for the Swift developer community, and we were really missing it!

https://swiftbysundell.com/special/swift-by-sundell-is-back/

Swift by Sundell is back! | Swift by Sundell

After a two-year hiatus, Swift by Sundell is finally back, with new articles published on a regular basis.

Swift by Sundell