The Develak Journal
The Develak Journal collects the iOS development guides our independent studio writes from shipping 34 apps on the App Store: Swift and SwiftUI, App Store submission, App Store Optimization and localization, explained step by step.
Every guide opens with the short answer, then walks through the details, the checklists and the trade-offs we met in our own apps.
Latest guide Guides 13 min read
What App Store guidelines 4.2 (Minimum Functionality) and 4.3 (Spam) actually say, why web wrappers, thin apps, templates and look-alike apps get rejected, where widgets and Live Activities fit, and how to reply to App Review or appeal.
Guides 15 min read
The complete 2026 reference for App Store screenshot and app preview specifications: 6.9-inch iPhone and 13-inch iPad pixel sizes, Mac, Apple Watch, Apple TV and Vision Pro, how scaling works, file formats, localization and how to design the first three screenshots.
Guides 13 min read
How to get auto-renewable subscriptions approved by App Review in 2026: guidelines 3.1.1 and 3.1.2, required paywall disclosures, Terms of Use and privacy links, Restore Purchases, App Store Connect setup, offers, StoreKit testing and the rejections to avoid.
Guides 9 min read
How ApexLap turns an iPhone into a lap timer for cars, motorcycles and karts: automatic start/finish detection, laps saved instantly, a free core and an optional Apex Pro, external GPS receivers, 44 languages at launch. Only public facts from the App Store listing.
Guides 10 min read
How Pillio, Develak’s medication reminder and dose log for iPhone and iPad, was shaped: flexible schedules, Apple Health and iCloud sync, Critical Alerts, accessibility, privacy without an account, and ten releases in public. Only verifiable facts from the App Store listing.
Guides 9 min read
How Xlocalize, Develak’s Mac app for .xcstrings files, approaches AI localization: Xcode’s native format preserved losslessly, per-key context, your own OpenAI, Claude or Gemini key in the Keychain, validation hints and honest error reporting. Only public facts from the Mac App Store.
Guides 13 min read
A practical 2026 guide to the iOS privacy manifest: the four PrivacyInfo.xcprivacy keys, every required reason API code, third-party SDK manifests and signatures, the Xcode privacy report, and how to fix ITMS-91053 and the other upload emails.
Guides 11 min read
How TestFlight works in 2026: internal vs external testers, groups, public links and tester criteria, Beta App Review, uploading and processing builds, export compliance, feedback and crashes, and fixes for Missing Compliance, stuck processing and expired builds.
Guides 12 min read
A practical guide to iOS app localization with Xcode String Catalogs and the Swift i18n APIs: String(localized:), LocalizedStringResource, plurals, InfoPlist permission strings, formatters, right-to-left layouts, pseudolanguage testing, App Store metadata and translation workflow.
From the guides
Short answers to common iOS questions, straight from our guides. Each one links to the guide that covers the topic in depth.
Up to 100 internal testers, who are App Store Connect users on your team, and up to 10,000 external testers per app, invited by email or public link. Each tester can install your builds on up to 30 devices.
From the guide: TestFlight guide (2026): internal and external testers, Beta App Review and public links
It is required as soon as your code uses a required reason API, which covers nearly every app since UserDefaults and @AppStorage are in the list. Listed third-party SDKs must ship their own. An app that uses none of these APIs and collects no data does not strictly need one, but adding a manifest with NSPrivacyTracking set to false costs little.
From the guide: iOS privacy manifest (PrivacyInfo.xcprivacy) in 2026: required reason APIs, SDKs and ITMS-91053
Xlocalize is a Mac app published by Develak that translates Xcode String Catalogs (.xcstrings) with OpenAI, Anthropic Claude or Google Gemini, using your own API key, while preserving plurals, device variations and substitutions. It is free to download, with an optional Premium subscription.
From the guide: Case study: Xlocalize, a Mac app that translates Xcode String Catalogs with AI
Pillio is an iPhone and iPad app published by Develak that reminds you to take medications and vitamins, logs every dose as taken, skipped or postponed, syncs with Apple Health and iCloud, and exports PDF reports for doctor visits. It is free to download, with optional monthly or annual subscriptions.
From the guide: Case study: Pillio, a medication reminder app built natively for iPhone
ApexLap is an iPhone and iPad app published by Develak that times every lap automatically on track for cars, motorcycles and karts, and adds telemetry, video overlays, lap comparison and external GPS or OBD-II data with the optional Apex Pro.
From the guide: Case study: ApexLap, a lap timer and telemetry app designed for iPhone track days
Usually because required information is missing: a functional link to the Terms of Use (EULA) or the privacy policy, either inside the app or in the App Store metadata, or the paywall doesn’t clearly show the plan’s length, the full billed price and what it includes. Read the rejection message: it lists exactly which items are missing and where.
From the guide: App Store subscriptions in 2026: how to pass App Review (guideline 3.1.2, paywall, rejections)
We design, build and publish native iPhone, iPad and Mac apps in Swift and SwiftUI, with the same care as our own 34 apps.