Senior Full-Stack Developer (Kotlin/Java)

Intellias; Poland; On-site; PLN 180,000 - 240,000; Full time

Job summary

Intellias in Poland seeks an experienced Android engineer to take end-to-end ownership of a modern mobile product, working across Android/Kotlin, backend services, and cloud deployment with cross-functional teams.

The role emphasizes reliability, security, and scalable architectures, with opportunities to influence product direction and mentor junior engineers.

Qualifications

• 6+ years of professional software development experience.
• Senior level in Android/Kotlin or Java/Spring Boot.
• Hands-on with Jetpack Compose and Kotlin coroutines.
• Experience with REST APIs and databases.
• Knowledge of MVVM or Clean Architecture.

Responsibilities

• Take end-to-end ownership of product features.
• Develop new mobile functionality and supporting backend services.
• Translate business needs into reliable technical solutions.
• Design clear interfaces and data flows across components.
• Implement reliable offline behavior and data synchronization.
• Maintain high engineering standards through automated testing and reviews.
• Investigate and resolve complex issues across layers.
• Contribute to architectural decisions.

Skills

Android Kotlin

Java Spring Boot

Kotlin Coroutines/Flow

MVVM/MVI architecture

Android Jetpack components

REST API integration

Docker/Kubernetes

CI/CD pipelines

Unit/Integration testing

English communication

Education

Bachelor's degree in Computer Science or related field

Tools

Jetpack Compose

Kafka

SQL/JPA

Git

Job description

Over 20 years of market experience, Intellias brings together technologists, creators and innovators in Europe, North and Latin America, and the Middle East. Join our international team and take the mission to solve the advanced tech challenges of tomorrow!

Project overview:

Our client is a large international company operating in the transportation and supply chain domain. The organization is investing in the modernization of its digital ecosystem and expanding the range of mobile solutions used to manage complex operational processes.

The project focuses on building a modern Android product that will help users coordinate daily transportation activities, access relevant information, and work more efficiently across different locations and operating conditions.

The engineer will join an established product development team and work with a modern Android and backend technology stack. The role provides an opportunity to contribute across the full feature lifecycle - from solution design and mobile development to backend integration, cloud deployment, monitoring, and continuous product improvement.

This is a long-term project with a strong focus on technical ownership, application reliability, scalability, security, and close collaboration between mobile, backend, cloud, and product specialists.

Requirements:

• 6+ years of professional software development experience
• Strong production experience across both Android/Kotlin and Java/Spring Boot, with senior-level expertise in at least one of these areas
• Strong knowledge of Kotlin, Android SDK, and modern native Android development
• Hands-on commercial experience with Jetpack Compose
• Practical experience with Kotlin Coroutines, Flow, StateFlow, and SharedFlow
• Strong understanding of MVVM or MVI, Clean Architecture, and multi-module Android applications
• Experience with Hilt or Dagger and Android Jetpack components, including ViewModel, Navigation, Room, WorkManager, and DataStore
• Experience with offline synchronization, REST API integration, and JSON serialization
• Strong Java and Spring Boot development experience, including microservices and REST API design
• Solid knowledge of JPA, Hibernate, SQL, relational databases, transaction management, and query optimization
• Experience with asynchronous and event-driven solutions using Apache Kafka or similar messaging technologies
• Good understanding of distributed systems, service-to-service communication, caching, error handling, and resilience patterns
• Hands-on experience with Docker, Kubernetes, Microsoft Azure, and preferably Azure Kubernetes Service
• Experience with Gradle, Maven, Git, and automated CI/CD pipelines, preferably GitLab CI/CD
• Strong testing experience covering unit, integration, API, and mobile UI testing using relevant frameworks such as JUnit, Mockito, Testcontainers, and Jetpack Compose UI testing
• Good understanding of application security, including OAuth2/OIDC, JWT, HTTPS/TLS, secure API design, secrets management, and OWASP principles
• Experience with application performance analysis, production troubleshooting, crash investigation, and monitoring
• Ability to make independent technical decisions, review code, and contribute to architecture discussions
• Upper-Intermediate or higher English communication skills

Nice to have:

• Kotlin Multiplatform or .NET MAUI
• Helm, Terraform, or other Infrastructure as Code tools
• Domain-Driven Design, CQRS, or Event Sourcing
• BLE or other hardware integration experience
• Experience modernizing legacy Java applications
• Experience with large-scale enterprise systems

Responsibilities:

• Take end-to-end ownership of product features, from technical design and implementation to release, monitoring, and production support
• Develop new mobile functionality and supporting backend services
• Translate business and product needs into reliable and maintainable technical solutions
• Design clear interfaces and data flows between mobile, backend, database, and messaging components
• Implement reliable offline behavior and data synchronization mechanisms
• Maintain high engineering standards through automated testing, code reviews, and static analysis
• Investigate and resolve complex issues across multiple application layers
• Improve application performance, stability, security, and scalability
• Contribute to architectural decisions and propose improvements to existing solutions
• Identify and address technical debt as part of ongoing development
• Support automated build, delivery, and deployment processes
• Collaborate closely with mobile, backend, cloud, product, and other cross-functional specialists
• Share technical knowledge and mentor other engineers where appropriate