Senior Mobile Engineer

Team Up Recruitment; Polska; Remote; PLN 180,000 - 260,000; Full time

Job summary

Team Up Recruitment is seeking a Senior Mobile/Backend Engineer to work on a large-scale fintech platform used by millions of customers. You will develop shared Kotlin Multiplatform logic for native Android and iOS, while also designing and building backend services using Java, Kotlin, and Spring Boot.

You will own features from design through deployment and production support. You will work in a fully remote setup within Poland, collaborating with an international team using English as the

Qualifications

• Senior-level experience in mobile app development with Kotlin.
• Deep understanding of Android or iOS architecture and design principles.
• Hands-on backend experience with Java and Spring Boot, APIs, and microservices.
• Experience on large-scale production systems.
• Familiarity with automated testing, CI/CD, and cloud environments.
• Ability to own features from design through deployment and production support.
• Strong communication and English for technical collaboration.

Responsibilities

• Develop shared business logic for native Android and iOS using Kotlin Multiplatform.
• Build and enhance customer-facing mobile features.
• Design and develop backend services and APIs with Java, Kotlin, Spring Boot.
• Improve performance, scalability, security, and reliability.
• Work with CI/CD, monitoring, and production environments.
• Collaborate with product, design, architecture, security, and platform teams.
• Contribute to technical decisions and maintain high engineering standards.

Skills

Kotlin

Android architecture

iOS architecture

Java

Spring Boot

CI/CD

Cloud environments

English proficiency

Tools

AWS

Docker

Kubernetes

Kafka

RabbitMQ

Job description

Join a team building a large-scale fintech platform used by millions of customers.

You will work on an established product processing millions of real-time financial transactions every month. Your scope will span mobile features, shared Kotlin Multiplatform logic, and backend services, with ownership from design through deployment and production support.

What you'll do

• Develop shared business logic for native Android and iOS applications using Kotlin Multiplatform.
• Build and enhance customer-facing mobile features.
• Design and develop backend services and APIs using Java, Kotlin, and Spring Boot.
• Improve application performance, scalability, security, and reliability.
• Work with CI/CD, monitoring, and production environments.
• Collaborate with product, design, architecture, security, and platform teams.
• Contribute to technical decisions, share knowledge, and maintain high engineering standards.

What we're looking for

• Senior-level commercial experience in mobile application development and strong Kotlin skills.
• A deep understanding of Android or iOS architecture and software design principles.
• Hands-on backend experience with Java and Spring Boot, APIs, and microservices.
• Experience working on large-scale, architecturally complex production systems.
• Familiarity with automated testing, CI/CD, and cloud environments.
• The ability to own features from design through deployment and production support.
• Strong communication skills and English proficiency sufficient for daily technical collaboration.

KMP experience is preferred, but we also welcome engineers with strong Android/Kotlin and Jetpack Compose experience.

You may be stronger in mobile or backend development, provided you have practical experience in both areas.

Nice to have

• Experience in fintech, banking, payments, or other regulated industries.
• Kafka, RabbitMQ, or other messaging technologies supporting event-driven architectures.
• AWS, Docker, and Kubernetes.
• Apple Pay, Google Pay, digital wallets, or payment integrations.
• Experience building SDKs, shared libraries, or modular mobile applications.
• Observability, performance optimisation, and production incident analysis.

What you can expect

• Fully remote work from within Poland.
• An international team with English as the daily working language.
• An opportunity to influence KMP adoption and technical decisions.
• Ownership of features used by millions of customers.