Full Stack Mobile Developer (Cross-Platform / Native)

We are looking for an experienced mobile engineer who takes ownership of delivery across iOS and Android, including reliable integration with backend services.
We hire engineers, not just framework specialists. Flutter and Dart will be your primary mobile technologies, alongside Swift, Kotlin, and native build tools. We value pragmatic problem-solving, first-principles thinking, and the ability to work confidently with unfamiliar tools and existing codebases.
Your first assignment will be a focused mobile infrastructure setup and stabilization sprint for an enterprise field-inspection system. You will work alongside a dedicated Senior Full Stack Developer responsible for the backend, with your primary ownership covering mobile applications, native builds, releases, and API integrations. This will lead into ongoing architecture and development across our project portfolio.

Who are we?
We are Out Of The Box Systems: a Ukrainian team specializing in Rust Development, AI Engineering, Computer Graphics, Automation, and Custom Software Development.
We value ownership, accountability, continuous learning, and practical problem-solving. Our team works remotely with clients from the USA, Canada, Europe, and other international markets.

Workload
Full-time remote collaboration
Direct communication with clients, technical leadership, and engineering teams
Immediate availability or the ability to join an active project within 1–2 weeks is a strong advantage

Responsibilities
Own mobile application delivery across iOS and Android, from codebase assessment and architecture to implementation and production release
Build and maintain Flutter applications, using Swift, Kotlin, and native SDKs for platform-specific functionality
Maintain and troubleshoot Gradle, Xcode, and CocoaPods configurations, including dependencies, build scripts, and platform compliance settings
Manage code signing, keystores, provisioning profiles, and automated delivery to TestFlight, the App Store, and Google Play internal and production tracks
Implement and debug API communication, authentication tokens, multipart file uploads, and cloud storage integrations such as AWS S3
Collaborate with backend and cloud engineers to trace integration issues end to end, validate API contracts, and resolve data flow problems
Audit existing codebases, resolve dependency issues, remove deprecated code and templates, and improve build performance and application stability
Adapt to new tools and SDKs as projects evolve; verify delivery through tests, logs, and agreed acceptance criteria

Required Skills
Strong commercial mobile development experience, including production applications built with Flutter and Dart
Proven experience shipping and maintaining applications on both the Apple App Store and Google Play
Practical experience with Swift and Kotlin, including reading, debugging, and modifying native code on both platforms
Confidence working with native build configurations and resolving issues involving Gradle, .properties files, R8/ProGuard, CocoaPods, or CMake as needed
Strong understanding of backend integration: consuming REST/WebSocket APIs, handling authentication and session tokens, implementing multipart uploads, and debugging network requests end to end using Postman, network profiling tools, or cURL
Understanding of asynchronous state management, caching, and offline-first synchronization
Experience with Git, CI/CD, automated testing, debugging, and performance profiling
Ability to navigate unfamiliar or poorly documented codebases, learn new tools, and deliver solutions independently
Clear communication and ownership: report progress, flag blockers early with precise technical evidence, and work reliably toward agreed deadlines
Upper-Intermediate English (B2) or higher

Preferred Skills
Hands-on backend development experience with NestJS, TypeScript/Node.js, and PostgreSQL
Experience with AWS services, particularly S3, RDS, ECS or App Runner, and secure configuration management
Experience stabilizing legacy applications or taking over projects with limited documentation
Experience with Rust or C++ and native library integration

What You Get
A defined initial sprint with dedicated backend support, followed by opportunities across our project portfolio
Diverse engineering challenges spanning mobile applications, cloud integrations, and distributed systems
Fast decisions, direct access to technical leadership, and minimal unnecessary meetings
Transparent, deliverable-driven compensation reflecting your skills, agreed scope, and execution
Professional growth through hands-on work, feedback, and collaboration
Long-term B2B collaboration with immediate project onboarding

How to Apply
Please send us:
A brief summary of your background and the applications you have brought to production on iOS and Android.
A link to your GitHub/GitLab profile or examples of technical problems you have solved across native or cross-platform stacks.
A short example of how you quickly learned an unfamiliar technology or resolved a difficult build or environment issue under pressure.
Your earliest available start date.