Building an unofficial Dumpert client for Apple TV with Swift 6 and SwiftUI

Rob Mulder  — Thu, 04 Jun 2026 09:37:03 +0000

Dumpert is a Dutch video site I've watched for years, but there's never been an Apple TV app, so I built one. DumpertTV is an unofficial, open-source tvOS client. Here's how it's put together and a few things that were more interesting than I expected.

Disclaimer up front: this project is not affiliated with Dumpert or DPG Media B.V. It's an independent app that uses the public Dumpert API.

The stack

Swift 6 with strict concurrency (complete mode) across every target
SwiftUI for all UI, tvOS 18+
XcodeGen so the .xcodeproj is generated from a project.yml and never committed
CloudKit, GroupActivities (SharePlay), Vision, AVKit, Swift Testing

One actor for the network, one source of truth for the UI

The whole networking layer is an actor. That makes per-request state like ETags and retry bookkeeping thread-safe without a single lock:

actor DumpertAPIClient {
    private var etags: [URL: String] = [:]

    func fetch<T: Decodable>(_ endpoint: APIEndpoint) async throws -> T {
        // Exponential backoff on 5xx + network errors; honours 304 Not Modified.
        try await fetchWithRetry(endpoint, attempt: 0)
    }
}

The UI reads from a single @Observable @MainActor repository injected through the SwiftUI environment — no Combine, no view models competing over the same state:

@Observable @MainActor
final class VideoRepository {
    private(set) var hotshiz: [MediaItem] = []
    let apiClient: APIClientProtocol   // protocol-backed for testing
}

ContentView()
    .environment(videoRepository)

Views just read repository.hotshiz; updates flow automatically. With Swift 6's strict concurrency on, the compiler kept me honest about every actor hop.

Things that were trickier than expected

tvOS focus + a top tab bar. Getting a Netflix-style hero carousel to behave with the focus engine took real care. It also made automating screenshots interesting — scripted remote input doesn't reliably drive the simulator, so I added #if DEBUG launch-argument hooks to jump straight to any tab/category for a capture script.
Face-centered thumbnails. Dumpert thumbnails are arbitrary crops, so I run Vision face detection and bias the crop toward detected faces. On a 55" screen the difference is night and day.
CloudKit delta sync with change tokens for watch progress, settings and search history — resume-where-you-left-off works across multiple Apple TVs.
Top Shelf extension that surfaces trending content on the home screen, sharing data with the app through an App Group.
SharePlay (GroupActivities) for synchronized "watch together" playback.

Testing

80+ unit tests with Swift Testing, covering API decoding, the CloudKit merge logic, search/filter state, and autoplay/up-next playlist navigation. Protocols (APIClientProtocol, CacheServiceProtocol) make the network and disk layers easy to mock.

Try it / read the source

Source (MIT): https://github.com/rm335/dumpert-apple-tv
DOC: https://rm335.github.io/dumpert-apple-tv/
Free public TestFlight beta: https://testflight.apple.com/join/TXTUMzEq