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I’m Writing an App

The last two weeks I’ve spent quite some time on evenings and weekends to work on an iOS app. I won’t tell you what it is though, it’s way too early for that.

This is the first post in a series and this one is about technologies and tooling.


I’m writing a native app in Swift and UIKit.

The decision against using React Native or any other third-party mobile technology was mostly because native feels better (to me), is often faster and gets new features first. Using React Native would have sped up the development process a lot (mostly because I know that technology and my Swift/UIKit knowledge is a little rusty), but I wanted it to be native and I’m in no rush.

The project was initially set up to use SwiftUI as it seems to be the future of iOS development, but I quickly hit some limits. More experienced iOS-Developers would have probably found a way around it, but I feel more at home with UIKit and it’s a stable, battle-tested technology.


Spending most of my working time writing Go I’ve come to value automatic formatting and good linting. For that I’m using SwiftFormat and SwiftLint, both with the default configuration. You can configure Xcode to automatically run those when building, which I highly recommend.

For dependency management I’ve started using Carthage, mostly because that was the defacto-standard when I last wrote an app. But I’ve switched over to Swift Package Manager because it has great Xcode-integration and is generally stable.

Most iOS developers have experienced their share of .xcodeproj-related merge conflicts or weird diffs. Generally I prefer all files in my project to be human-readable. For that I’ve used XcodeGen, which allows you to define your project in a simple project.yml and ignore your project with these lines in you .gitignore:


That means that on CI, new clones or changes in project.yml you need to install XcodeGen and run xcodegen generate to set it up, but for me that’s worth it.

Talking about CI, I’ve set up Fastlane for linting and testing. It allows easy definition of rules and automatic TestFlight or even AppStore submissions (including taking screenshots), which is awesome. It also has a ton of plugins.

Since Travis CI costs a small fortune for private repositories I’ve migrated away and now use GitHub Actions. It took some time to configure it right, so here’s my .github/workflows/ci.yml, hoping it’s useful for some people:

name: CI

on: [push]

    runs-on: macos-latest
      - run: sudo xcode-select -s /Applications/Xcode_11.5.app/Contents/Developer
      - name: Checkout code
        uses: actions/checkout@v2
      - name: Cache Bundler
        uses: actions/cache@v2
          path: vendor/bundle
          key: $-gems-$
          restore-keys: |
      - name: Cache Swift Package Manager
        uses: actions/cache@v2
          path: .build
          key: $-spm-$
          restore-keys: |
      - name: Install dependencies
        run: |
          bundle update --bundler
          bundle install
          brew install xcodegen swiftlint swiftformat
      - name: Generate Xcode project
        run: xcodegen generate
      - name: Lint
        run: bundle exec fastlane lint
      - name: Test
        run: bundle exec fastlane test

That’s my setup so far. If you have any questions or suggestions, hit me up.