Senior Mobile App Developer

📍 Copenhagen · Full-time · On-site

About Goodiebox

Every month more than 70,000 members across 13 markets receive our curated beauty subscription box, designed to create happy moments of me-time and self-care.

We are on a mission to inspire and empower people to live happier lives, one happy moment at a time.

And we believe that doing good for yourself is a force for progress. That gives energy to do good for others too. Happy fuels happy.

Our Mobile App Success Story

In January 2025, we launched the Goodiebox mobile app — and the results have exceeded all expectations:

• 📱 Launch: January 2025

• 👥 Active users: 50,000+

• 📊 Monthly sessions: 350,000+

• 🚀 Growth: Rapidly expanding across all markets

The app is already creating countless happy moments for our community, but this is just the beginning. We're looking for a Senior Mobile App Developer to take ownership and shape the future of our mobile experience.

The Role

You'll be the architect of happiness in our members' pockets.

As our Lead Mobile Developer, you'll take full ownership of the Goodiebox app, transitioning from our external development partners to drive the product forward internally. Working closely with our Copenhagen-based Tech-Team and collaborating daily with our App Team (project managers, UX designers, marketers, and content creators), you'll have the unique opportunity to impact how tens of thousands of people experience joy through our platform. You'll be the only mobile developer focusing on technical aspects and collaborating and working autonomously while partnering closely with cross-functional stakeholders.

Our Tech Stack

• Platform: Kotlin Multiplatform Mobile (KMM) with shared business logic in composeApp

• UI Frameworks: Jetpack Compose (Android) and Swift/SwiftUI (iOS)

• Networking: Ktorfit (Ktor-based) for REST API consumption

• Dependency Injection: Koin

• Firebase: Crashlytics + Google Services

• Integrations: Facebook Login, Klaviyo marketing platform

• Build System: Gradle Kotlin DSL, KSP, BuildKonfig, version catalogs

• CI/CD: GitHub Actions for automated build & deployment

• Project Management: Agile workflows with Jira/Trello/GitHub Issues

• Development: AI-first approach using tools like Cursor AI

What You'll Be Doing

Cross-Platform Development:

• Maintain and extend our KMM shared codebase for efficient cross-platform development

• Build responsive, native user experiences using Jetpack Compose (Android) and Swift/SwiftUI (iOS)

• Implement new features from technical design through release and iteration

Technical Architecture:

• Make architectural decisions as the sole mobile developer

• Integrate with REST APIs using Ktorfit networking layer

• Maintain clean architecture using Koin dependency injection

• Keep Gradle Kotlin DSL, KSP, BuildKonfig, and version catalogs optimized

DevOps & Deployment:

• Own the complete GitHub Actions CI/CD pipeline

• Manage app store deployments including Android keystore and iOS provisioning profiles/certificates

• Maintain Firebase Crashlytics monitoring and error tracking

• Handle app signing and release management for both platforms

Integration & Maintenance:

• Ensure seamless Facebook Login and Klaviyo integration

• Debug, fix issues, and optimize performance across both platforms

• Keep dependencies and build systems up to date

• Work within Agile workflows using project management tools

AI-Enhanced Development:

• Leverage Cursor AI and other AI tools for enhanced productivity in coding, testing, and documentation

What We're Looking For

Essential Experience:

• 5+ years of professional mobile app development

• Strong Kotlin expertise with proven KMM (Kotlin Multiplatform Mobile) experience

• Cross-platform UI development using Jetpack Compose and Swift/SwiftUI

• Production app deployment experience with Google Play and App Store

• Solo developer capability — able to work independently and make technical decisions

Technical Expertise:

• API Integration: Hands-on experience with REST APIs, preferably using Ktor/Ktorfit

• Architecture: Experience with Koin dependency injection and clean architecture patterns

• Build Systems: Proficiency with Gradle Kotlin DSL, KSP, BuildKonfig, and version catalogs

• DevOps: Experience with GitHub Actions CI/CD pipelines and automated deployment

• Firebase: Setup and management of Firebase Crashlytics and Google Services

• Third-party SDKs: Experience with Facebook Login, Klaviyo, and similar integrations

Mobile Development Skills:

• Testing: Experience with JUnit, Kotest, MockK, and automated testing strategies

• App Store Management: Expert knowledge of Android keystore, iOS provisioning profiles, and certificate management

• Performance: Mobile performance profiling, crash analysis, and cross-platform debugging

• Security: Understanding of GDPR compliance, secure storage, and data privacy

Working Style:

• Independent: Ability to work as the sole mobile developer with minimal supervision

• Product-minded: Balance technical excellence with business outcomes and user experience

• Cross-platform thinking: Strong understanding of shared logic patterns and platform-specific implementations

• AI-enthusiastic: Excited about using AI tools like Cursor AI to boost productivity

• Agile-oriented: Experience working in Agile environments with project management tools

Why Join Goodiebox?

Direct Impact:

• Own a mobile platform used by 50,000+ active members

• Directly influence the happiness and daily experiences of thousands of people

• Work with a proven, rapidly growing product expanding across 13 markets

Technical Growth:

• Full ownership of technical decisions and architecture

• Work with modern cross-platform technology (KMM, Compose, SwiftUI)

• AI-first development environment with cutting-edge tooling

• Opportunity to build and scale a high-performance mobile platform

Company Culture:

• Mission-driven company focused on spreading happiness and positive impact

• Collaborative Copenhagen-based team environment

• Autonomy and ownership in your role as the lead mobile developer

• Modern development practices with quality-first approach

Ready to Create Happy Moments Through Code?

If you're passionate about cross-platform mobile development, excited about working independently with modern tech stacks, and want to own a product that brings joy to thousands of people daily, we'd love to hear from you.

Join us in Copenhagen and help us spread happiness, one app interaction at a time.