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SwiftLee 2023: A Year in Review

Time flies when you’re having fun, and 2023 has definitely been one of those years. It’s been a year full of achievements, international conferences, and many articles & newsletters. It’s also been the year of Apple Vision Pro, Xcode 15, and Swift 5.9.

If you follow my newsletter, you’ll know I like working structured with clear goals for every quarter. This year, I’ve grown much higher than expected for SwiftLee and RocketSim. Before we dive into that, let’s start with this year’s most popular articles.


My blog reached over 1 million users this year, resulting in over 2.3 million page views. I’ve continued to publish an article every week, which results in a consistent pace of visitors. A big thanks goes out to all the sponsors I’ve had this year, and I can’t wait to continue growing in 2024!

While I’ve published close to 52 new articles this year, there have been a few most popular ones:

1. Async await in Swift explained with code examples

Clearly, you’ve all started adopting async/await in your projects. My in-depth article has been the most popular one for two years now. I’m sure you’ll be excited to hear I’ve big plans for 2024 in this area since I love the Swift Concurrency framework. Stay tuned!

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2. MainActor usage in Swift explained to dispatch to the main thread

When you start working with the new Concurrency framework, you’ll soon enough run into questions around @MainActor usage and main thread dispatching. Number two in the list of most popular articles this year!

3. Testing push notifications on the iOS simulator

I was happily surprised to see this article as being the third most popular one of 2023. Testing Push Notifications can be time-consuming, but you’ll be much more productive with the technique and developer tool described in this article.

SwiftLee Weekly

I started with 8000 subscribers in 2022 and 12.000 at the beginning of 2023. I’m super happy to say my newsletter continued to grow towards 17.000 today! The newsletter continued promoting jobs and monthly giveaways, adding more value to subscribers than in earlier years.

Make sure to subscribe now if you haven’t done so yet, as I’ve got big plans for next year!

SwiftLee Jobs

Of all the things I’ve done, it’s SwiftLee Jobs that I struggled with the most. While The SwiftLee Talent Collective continued to grow, I’m not happy with how it turned out. I’m looking at improvements as we speak, hoping to increase value for those looking for a new job. More updates will follow next year.


My most successful project of the year has been RocketSim. In early 2022, I started tracking my Monthly Recurring Revenue (MRR) at $84, growing it to $1054 at the end of 2023.

RocketSim MRR grew much more than expected in 2023.
RocketSim MRR grew much more than expected in 2023.

This year, I decided to work one day a week on this side project to increase its value, resulting in an MRR of $4500 today. If I combine that with team licenses, it’s a total Annual Recurring Revenue of $62.000.

Revenue is a great way to measure growth, but it’s not only money that speaks to performance:

  • Daily active users increased by 300%
  • Those users created over 3000 recordings
  • 43.000 App Actions were launched
  • 4.000 designs were compared

These are incredible numbers, especially considering some features only arrived throughout the year.

Finally, I’ve focused solely on improving the existing app experience this quarter. I’ve implemented many bug fixes and UX improvements based on issues created on GitHub. I started several pricing experiments and focused on improving the onboarding flow. Fun fact (or not so fun, really): only 60% of those who install RocketSim will actually see the side window. In other words, 40% of users don’t experience RocketSim’s added value, allowing for so much growth potential. I can’t wait to continue this journey next year.

What’s next?

Looking back at 2023 makes me incredibly proud but highly motivated at the same time. I always feel like I’m just getting started since there are so many more ideas that I’d love to make a reality.

One thing I did realize this year after speaking at several conferences: I really enjoy making you a better developer. The feedback you’ve given me throughout the year is so fulfilling and highly motivating, making me want to share even more education in 2024. Therefore, I want to focus on reaching even more developers next year, while increasing the quality of SwiftLee, SwiftLee Weekly, and my other side projects.

Altogether, I created this outline of my goals:

  • Publish 3 courses on App Development. Yes, this is new! But I’ve already started investigating quite a bit. I truly believe there’s a large potential in teaching you some of the development techniques I learned over the years via courses. Some of these are hard to describe via articles, so this will be a great one.
  • Increase the quality of SwiftLee Weekly and grow towards 25.000 subscribers.
  • Improve the SwiftLee reading experience, as well as the quality of content. Grow towards 3 million page views and 1.5 million users.
  • RocketSim will receive some major updates based on the user-driven in-app roadmap. I aim to reach the $10.000 MRR by the end of the year.

I’ve purposely defined these goals using ambitious numbers since it will challenge me to stretch and improve. This technique has worked great for me so far, as it challenges me to go the extra mile. Hopefully, you’ll be joining me on this journey, and make sure to follow me along.


2023 has been an incredible year with a lot of growth. Reflecting on my achievements has been fulfilling, motivating me to keep improving next year.

Thanks a lot for your support, enjoy the last few days of this year, and all the best for 2024!