Jobs

We are looking for a Middle Java Engineer with Kotlin to join our team in Poland!

As a Middle Java Engineer, you’ll join client's AI team, where we’re shaping the future of shopping with leading-edge Agentic AI solutions. Together, we’re building intelligent systems that not only enhance the experience for sellers and buyers but also set new standards for innovation - just like the boldest ideas coming out of Silicon Valley. Become part of our dynamic AI R&D environment, where your creativity and engineering skills will drive the next generation of intelligent shopping experiences.

Our California-based client is a global e-commerce company that operates one of the largest and most established online marketplaces. For over 20 years, they have been connecting millions of sellers and buyers across more than 190 countries and territories. Their platform supports a wide range of products - from everyday items to unique and hard-to-find goods 0 and helps individuals and businesses grow by reaching a global audience. The company continues to develop its services with a focus on improving technology, user experience, reliability, and trust.

Responsibilities:

• Design and develop new solutions (approximately 70% greenfield development, 30% optimization and maintenance).
• Implement clean, testable, and efficient services using Kotlin on JDK 17, ensuring interoperability with existing Java components.
• Collaborate closely with Data Science and Machine Learning teams to design and implement LLM-driven workflows.
• Participate in architectural and code reviews across a modern technology stack (Kotlin/Java, Spring Boot 3, Reactor).
• Take ownership of service reliability, including CI/CD pipelines (GitHub Actions) and system observability.
• Work within a Scrum framework (two-week sprints, CET core working hours) in collaboration with product owners based in the US (EDT) and Europe.

Requirements:

• 3+ years of building backend services in Java/Kotlin (and happy to deepen Kotlin).
• Solid Spring ecosystem knowledge (Spring Boot 3, Spring Data, Spring Cloud).
• Hands-on with a NoSQL store (MongoDB, DynamoDB, or Cassandra).
• Familiarity with API styles (REST, gRPC, GraphQL) & distributed design patterns.
• Very good spoken and written English (C1)
• BSc or MSc in Computer Science, Engineering, or a relevant field

Nice to have:

• Kafka
• Docker + Kubernetes
• ETL pipelines
• Vector search / LLM integration.

We offer*:

• Flexible working format - remote, office-based or flexible
• A competitive salary and good compensation package
• Personalized career growth
• Professional development tools (mentorship program, tech talks and trainings, centers of excellence, and more)
• Active tech communities with regular knowledge sharing
• Education reimbursement
• Memorable anniversary presents
• Corporate events and team buildings
• Other location-specific benefits

Senior Kotlin Developer (Remote)

About the Company

We are an innovative technology company developing high-performance mobile applications. Our team works on challenging projects for clients across various industries, using cutting-edge technologies to deliver exceptional mobile experiences.

About the Position

We are looking for an experienced Senior Kotlin Developer to join our mobile development team. This is a fully remote position.

Requirements:

• 4+ years of commercial experience in Android development
• Strong expertise in Kotlin and Java
• Profound understanding of Android SDK, different versions of Android, and how to deal with different screen sizes
• Experience with RESTful APIs, JSON, and data parsing
• Knowledge of SOLID principles, clean architecture, and design patterns
• Experience with dependency injection frameworks (Dagger/Hilt, Koin)
• Proficiency with Kotlin Coroutines, Flow, and LiveData
• Experience with Room, SQLite, or other local storage solutions
• Knowledge of unit testing and UI testing frameworks (JUnit, Espresso, Mockito)
• Experience with version control systems (Git)
• Upper-intermediate English level (B2)
• Strong problem-solving skills and attention to detail

Nice to have:

• Experience with Jetpack Compose
• Knowledge of Kotlin Multiplatform Mobile (KMM)
• Experience with CI/CD pipelines
• Understanding of reactive programming (RxJava/RxKotlin)
• Experience with Firebase services
• Knowledge of agile development methodologies
• Experience with GraphQL
• Experience with performance optimization and profiling tools

Responsibilities:

• Design, develop, and maintain high-quality Android applications
• Write clean, maintainable, and efficient code
• Collaborate with cross-functional teams to define, design, and ship new features
• Identify and correct bottlenecks and fix bugs
• Help maintain code quality, organization, and automatization
• Participate in code reviews and mentor junior developers
• Research and implement new mobile technologies to maximize development efficiency
• Contribute to continuous improvement of development processes

We offer:

• Competitive salary range: $4500-7000 per month based on experience and skills
• 100% remote work
• Flexible working hours
• Professional growth opportunities
• Interesting and challenging projects
• Regular knowledge sharing sessions
• Medical insurance
• Paid vacation and sick days
• Professional development budget

We are looking for a Senior Mobile Developer to join our project related to design and development of IoT software for medical industry. You’d be working on project focusing on connecting sensors via Bluetooth to native applications that inform users about the status of devices. It involves big scale applications based on multiple languages, some accessibility features and BLE Connectivity.

Skills: 

• Quality focused mindset, including unit testing 
• Strong software development skills 
• Experience with modern software engineering practices 
• Extensive experience with mobile development 
• Extensive Kotlin experience 
• Experience with Android and iOS development 
• Experience with Kotlin Multiplatform 
• Experience with Jetpack Compose UI 
• Experience with Swift UI 
• Experience working in a regulated industry (i.e. under IEC 62304) 
• Experience with Git 
• Experience with Azure DevOps 
• Experience with integration to backend APIs and/or Bluetooth devices 
• Good verbal and written English skills 

We are looking for a skilled Backend Developer with expertise in both mobile/client application development using Flutter/Dart and backend development in Kotlin. The ideal candidate will be responsible for designing robust APIs and ensuring our applications' security, optimization, and scalability. You will collaborate closely with analysts, QAs, and DevOps teams to deliver high-quality software solutions. 

Responsibilities: 

• Build and maintain backend services using Kotlin.
• Develop mobile and client applications using Flutter/Dart.
• Design, implement, and document efficient and secure APIs. 
• Ensure application security, performance optimization, and scalability. 
• Collaborate with cross-functional teams, including analysts, QA testers, and DevOps. 
• Participate in code reviews and contribute to improving development processes and standards. 

Qualifications: 

• 3+ years of experience with any JVM language (Kotlin, Java, Scala, or Clojure). 
• Nice to have some experience with Flutter/Dart, or a strong willingness to learn. 
• Experience with React or Angular, Vue.js will be a plus
• Proven experience working with relational databases. 
• Demonstrated experience in creating REST APIs. 
• Solid understanding of design patterns and microservices architecture. 
• Excellent communication and teamwork skills. 

Nice to Have: 

• Familiarity with continuous integration and continuous deployment (CI/CD) processes. 
• Experience with performance tuning and application scalability strategies. 
• Proactive problem-solving skills and a keen attention to detail. 

About the Project:

We’re collaborating with a leading company in financial crime prevention and fraud detection. Their platform empowers businesses to assess risk in real time, processing millions of data points per second to detect and prevent fraudulent activity on a global scale.

Currently, we are in the migration phase, modernizing the API infrastructure to ensure seamless compatibility between legacy and new systems. After this phase, we’ll move into platform enhancement, focusing on performance optimization, feature expansion, and system scalability.

You’ll join a highly skilled team working on real-world challenges with high-load systems, modern cloud-native solutions, and advanced communication protocols. This is an excellent opportunity for someone eager to grow fast and gain hands-on experience with cutting-edge technologies in a demanding but rewarding environment.

Project Highlights:

• Current focus: Migration and modernization of API infrastructure.
• Next phase: Platform enhancement, scalability improvements, and feature development.
• Load profile: High throughput, real-time fraud detection.
• Team: 2 Back-End Developers, 1 Solution Architect, 1 Project Manager.
• Methodology: Agile (Scrum), 1-week sprints, daily stand-ups, regular demos.
• Tooling: Slack, Jira, Google Meet.

What You’ll Do:

• Design and implement scalable, cloud-native Kotlin-based microservices.
• Contribute application API and performance optimization efforts.
• Leverage Kafka and gRPC for high-throughput, efficient communication between services.
• Work with PostgreSQL (Yugabyte) and jOOQ to optimize data operations.
• Deploy and manage services in AWS and GCP using Kubernetes and Docker.
• Collaborate with DevOps engineers for streamlined, containerized deployments.
• Engage with stakeholders to ensure seamless integration and alignment on goals.

What We’re Looking For:

• Proven experience with Kotlin and Spring Boot in production environments.
• Deep understanding of microservices architecture, API development, and cloud platforms.
• Solid knowledge of Kafka, including Kafka Connect and transactional outbox/inbox patterns.
• Hands-on experience with gRPC and Protobuf for service-to-service communication.
• Proficiency in PostgreSQL, Yugabyte, jOOQ, and SQL performance tuning.
• Experience with Kubernetes, AWS, GCP, and containerized environments.
• Strong problem-solving skills and ability to make architectural decisions.
• Great communication skills and the ability to collaborate with both technical and business teams.

Why Join FreySoft?

🌍 International team within the EU time zone, flexible schedules.

🚀 Cutting-edge technologies and high-load, real-world challenges.

🎯 Growth-focused culture – grow into leadership, own features, or mentor juniors.

💡 Innovative environment – leverage AI/LLM tools to boost development speed and quality.

💰 Competitive compensation based on experience and skills.

🤝 Collaborative and professional team that values initiative, autonomy, and continuous learning.

At FreySoft, we believe in empowering developers to drive innovation and grow through real impact. If you’re passionate about backend development, love solving complex problems, and want to work with some of the most modern tools in the industry – let’s talk.