Stewart Lynch News
​2025-19

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​https://stewartlynch.kit.com​

Mastering Unit Conversions in Swift (Without the Headaches!)

Last week, I released a video showing how to take the pain out of unit conversions in your Swift apps. I covered how to use Swift’s powerful Measurement API to safely convert, format, and even create custom units — all with practical, real-world examples.

Whether you’re building a fitness tracker, a cooking app, or anything that involves distance, temperature, or weight, this video will help make your code more expressive and error-proof.

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Protect Your API Keys in Swift — New Video Coming Sunday!

Ever wondered how easy it is for someone to steal an API key from your iOS app, even after it’s released?

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In this coming Sunday’s video, I’ll show you just how exposed your keys can be and guide you step by step through securing them using Swift ConfidentialKit.

We’ll build a simple app with the Merriam-Webster Thesaurus API and learn how to keep your keys safe from prying eyes.

Don’t miss it!

Almost ready for WWDC25 content!

I’ve just about finished editing my last video before I start rolling out my WWDC25 series. This new batch of videos will kick off on the first Sunday in August.

As always, I’ll begin with What’s New in Xcode 26. This year, it’s a bit more challenging. The most exciting feature in Xcode 26 is the new integration with ChatGPT, which requires macOS 26. I’m fortunate to have a second Mac running the beta, but like many of you, I’m not ready to install it on my main machine just yet.

To demonstrate the new code assist features, I’ll have to mirror my MacBook Air (which has macOS 26 installed) to my Mac mini that is still running Sequoia. Because of this, I’m considering making two separate videos. The first will cover all the new features in Xcode 26 that you can use right now on Sequoia. The second will highlight the new code assist features that require macOS 26.
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You’ll still be able to develop apps for iOS 18 on Sequoia, but you won’t be able to use the new Foundation Model framework. This framework is arguably the most exciting API this year, but it only works on iPhone 15 Pro and later, which limits your install base. For that reason, I’ll probably hold off on creating Foundation Model videos until after I return from my European vacation in October.

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A question I get asked a lot is how I learn the new APIs and plan my videos after WWDC. Unlike some other creators, I prefer to wait for a few beta releases before diving in fully. That doesn’t mean I’m not exploring in the meantime. I use Raindrop.io to collect and organize articles, videos, and posts from bloggers, YouTubers, and anyone else who shares interesting new discoveries. ​ If you’re curious, I made a video about Raindrop.io here: https://youtu.be/r9wa_Yuk678. ​ Right now, I have over 100 WWDC25-related bookmarks. Today, I went through them again and sorted them into subcollections that will form the basis of my upcoming videos. Some topics will lead to more than one video, while others might never get covered.

I don’t really follow a strict plan. I start exploring a topic and often discover there’s much more to it than I expected. That pushes me to dig deeper.

I usually come up with a project that forces me to explore as many aspects as possible. Sometimes this turns into a single video, and other times, like I expect with Foundation Models, it will turn into a series.

That’s part of the excitement. I never know exactly where it will lead, and I feel very lucky to have the time and freedom to share what I learn with all of you.

Stepping Out as a Developer at Apple’s Vancouver Event

Last week, I attended the Exploring the Biggest Updates from WWDC25 event in Vancouver, my hometown. While I’ve been to many Apple events before as an educator, this was my first time attending as a developer.

I’ll admit it: I’ve struggled with imposter syndrome and often hesitate to put myself out there among other developers. Thankfully, my experience at Deep Dish Swift in Chicago earlier this year was a turning point. I discovered just how friendly and welcoming the Swift community is, which gave me the confidence to show up and connect.

It was even easier this time around, as I ran into three people I had met in Chicago. On top of that, several attendees recognized me and thanked me for my videos — always a reassuring and motivating moment.

Content-wise, the event mostly recapped the main WWDC highlights, and many of the examples were familiar. The presenters, who came from across Apple (including as far as Brazil), did a fantastic job nonetheless.

There was a strong focus on Vision Pro. While I haven’t taken the plunge yet — the price point is still too high for me — I’m sure I’ll jump in once it becomes more accessible.

Overall, it was a fantastic opportunity to learn, connect, and feel part of the community. I look forward to more chances like this in the future.

My Other Stuff

Channel Listing App

A Searchable Mac app containing a list of all of my YouTube videos including the ability to watch them in the app and download starter and completed source code

Free on Gumroad

CustomGPT

A custom ChatGPT that has indexed the transcripts of my videos.
Add to your ChatGPT Sidebar​

Smile4Me Course

Learn how to build a multi-targeted app using a Jokes API.
Don't let the low cost of the course fool you into believing that low cost means low content. 6.5 hours of content and 56 videos.

​Enrol in the course

Affiliate Links

Below are a number of affiliate links for products that I not only endorse but use all the time. I will never endorse something that I do not believe in.

AppScreens

Simply the best way to create your Screenshots for your AppStore connect submissions
​https://appscreens.com/?via=92e164​

RocketSim - Build Apps Faster 

This is an invaluable tool when working with the simulator in Xcode.

   https://gumroad.com/a/122988499/ftvbh 

BigMountain Studio Books 

Mark Moeykens is a master at creating SwiftUI reference books. I have purchased every one of these books and refer to them all the time.

Use this link and we both will benefit

​https://www.bigmountainstudio.com/a/77jt8​