Senior KMP Engineer (Mobile & Backend)

Integral Solutions - Informatica Distributor; United States; Remote; USD 87,000 - 93,000; Full time

Job summary

Integral Solutions - Informatica Distributor is seeking a Senior Fullstack Mobile Engineer to own development across mobile platforms and backend services. The role emphasizes Kotlin Multiplatform, Kotlin, Java, and Spring Boot within a modern fintech-like digital platform serving millions of users.

The position is remote from Poland, with a B2B contract and monthly net salary in euros. You will influence architecture, collaborate across teams, and help scale production systems and

Qualifications

• Strong commercial experience in mobile app development with Kotlin or Kotlin Multiplatform.
• Deep understanding of modern Android or iOS architectures and software design principles.
• Strong Kotlin skills and production-grade applications.
• Some backend development experience with Java, Spring Boot, APIs, and microservices.

Responsibilities

• Develop shared business logic across mobile platforms using Kotlin Multiplatform (KMP).
• Design and build backend services and APIs using Java, Kotlin, and Spring Boot.
• Build and enhance customer-facing mobile features used by real customers every day.
• Work with cloud services, CI/CD, observability, monitoring, and production systems.
• Improve scalability, reliability, performance, security, and user experience.
• Collaborate closely with product, design, architecture, security, and platform teams.
• Drive engineering excellence through technical leadership, mentoring, and best practices.

Skills

Kotlin Multiplatform

Mobile development

Android architectures

iOS architectures

Java

Spring Boot

APIs & microservices

CI/CD

End-to-end ownership

Team collaboration

Job description

Senior Fullstack Mobile Engineer (KMP/Java)

Job title: Senior Fullstack Mobile Engineer (KMP/Java)

Location: Remote anywhere from Poland
Work mode: Remote
Type of cooperation: B2B contract
Salary range: B2B: 7000 - 7500 Euro/month - netto

About the company/project:

Build the Next Generation of Digital Financial Products

Join a team building one of the largest digital financial platforms in its market, serving millions of customers and processing millions of real-time financial transactions every month.

This is a unique opportunity to work on products that have become a natural part of users' daily lives, delivering fast, secure, and seamless financial experiences at scale. As a Senior KMP Engineer, you will contribute across the entire technology stack - from customer-facing mobile applications and shared cross-platform logic to backend services, APIs, cloud infrastructure, and large-scale production systems.

Our core technology stack includes Kotlin, Kotlin Multiplatform (KMP), Java, and Spring Boot.

• Build products used daily by millions of customers.
• Work on large-scale, business-critical systems processing millions of real-time financial transactions every month.
• Take full end-to-end ownership of features, from design and implementation to deployment and production support.
• Help shape the future of our mobile platform strategy through Kotlin Multiplatform (KMP).
• Collaborate in small, high-impact teams where engineers have real influence on technical decisions.
• Solve challenging problems across mobile development, backend services, cloud infrastructure, scalability, reliability, and security.
• Be part of an engineering culture where AI is used every day as a practical development tool, accelerating delivery and enabling engineers to focus on solving meaningful business and technical challenges.

Responsibilities:

What You'll Do

• Develop shared business logic across mobile platforms usingKotlin Multiplatform (KMP).
• Design and build backend services and APIs usingJava,Kotlin, andSpring Boot.
• Build and enhance customer-facing mobile features used by real customers every day.
• Work with cloud services, CI/CD, observability, monitoring, and production systems.
• Improve scalability, reliability, performance, security, and user experience.
• Collaborate closely with product, design, architecture, security, and platform teams.
• Drive engineering excellence through technical leadership, mentoring, and best practices.

You are an ideal candidate if you have:

What We're Looking For

We are looking for strong engineers who enjoy solving product and technical challenges across multiple layers of the technology stack.

• Strong commercial experience in mobile application development with Kotlin or Kotlin Multiplatform.
• Deep understanding of modern Android OR iOS architectures and software design principles.
• Strong Kotlin skills and experience building high-quality, production-grade applications.
• Some backend development experience withJava, Spring Boot, APIs, and microservices
• Familiarity with distributed systems, event-driven architectures, and modern engineering practices.
• Experience with CI/CD, automated testing, and production environments.
• Ability to take end-to-end ownership of features from design through production.
• Strong communication and collaboration skills.

Nice to have:

Experience in fintech, banking, payments, or other regulated industries.

Experience withApple Pay, Google Pay, wallet technologies, or payment integrations.

Experience building modular mobile applications, SDKs, or shared libraries.

Experience with observability, performance optimization, and production incident analysis.