Full-stack (Java/Kotlin) Engineer (m/f/d) – Team Payments

Full-Stack Engineer (Backend Focus – Kotlin)

At Flix, we combine technology, innovation, and real-world impact to shape the future of sustainable mobility. We offer a collaborative environment where engineers have ownership, growth opportunities, and the chance to build products used by millions of travelers worldwide.

As a Full-Stack Engineer with a strong backend focus on Kotlin, you will join our Payments Team within the Demand Division and help build the systems that power our global payment experience.

Your work will directly influence:

• Payment authorization and conversion rates.
• Transaction processing speed and reliability.
• Revenue generation and payment efficiency.
• Revenue protection and fraud prevention initiatives.
• Integration of local payment methods across international markets.

Our technology stack includes:

• Backend: Kotlin, Spring Boot
• Frontend: TypeScript, React.js
• Legacy Systems: PHP

The Payments Team consists of:

• 4 Backend Engineers
• 2 Frontend Engineers
• 1 Engineering Manager

What You’ll Do

• Design, build, and maintain payment systems that operate securely and at scale.
• Develop and deliver features used by millions of customers worldwide.
• Write clean, maintainable, and production-ready code.
• Take ownership of features throughout the entire development lifecycle:
  • Requirements and design
  • Implementation
  • Testing
  • Deployment
  • Monitoring and maintenance
• Collaborate closely with Product, UX, Frontend, Backend, and Business stakeholders.
• Participate in code reviews and pair programming sessions.
• Continuously improve existing services and modernize legacy systems.
• Contribute to engineering best practices and team knowledge sharing.

What We’re Looking For

• 3–4 years of professional experience developing backend or full-stack web applications.
• At least 2 years of commercial experience working with Kotlin.
• Experience with frontend development using:
  • JavaScript
  • TypeScript
  • Modern frameworks such as React.js, Vue.js, or Angular
• Willingness to work with legacy PHP systems when required.
• Strong object-oriented programming skills.
• Understanding of clean architecture principles and maintainable software design.
• Experience working with relational databases.
• Hands-on experience with automated testing, including:
  • Unit testing
  • Integration testing
  • Component testing
  • UI testing
• Experience deploying applications through CI/CD pipelines.
• Strong written and verbal English communication skills.
• Collaborative mindset with a team-oriented approach.

Nice-to-Have Skills

• Experience with containerization and orchestration technologies such as:
  • Docker
  • Kubernetes (K8s)
• Knowledge of event-driven architectures and messaging platforms such as Kafka.
• Experience working with AWS or other cloud platforms.

We recognize that great candidates come from diverse backgrounds. If you believe you can make an impact in this role, we encourage you to apply even if you don’t meet every requirement.

What We Offer

Travel Benefits

• 12 complimentary Flix travel vouchers per year.
• 12 discounted travel vouchers for friends and family.

Flexible Working

• Work from another location for up to 60 days per year, depending on role eligibility.
• Hybrid work model that combines collaboration and flexibility.

Health & Wellbeing

• Confidential counseling services and wellbeing support.
• Access to stress management resources and professional guidance.
• Coverage available for employees and up to four family members.

Learning & Development

• Language courses and learning programs.
• Professional training opportunities.
• Expert-led workshops and development sessions.

Mentorship Program

• Connect with experienced colleagues for guidance and career development.
• Gain insights from industry professionals across the organization.

Why Join Flix?

At Flix, we empower our teams to challenge the status quo and create innovative solutions that transform mobility worldwide.

• Work on products used by millions of travelers.
• Build technology that makes transportation smarter, greener, and more accessible.
• Take ownership of meaningful projects with real business impact.
• Collaborate with talented engineers in a fast-growing international company.
• Help shape the future of global mobility through technology and innovation.

If you’re passionate about building scalable payment systems and want to contribute to products that make travel more sustainable and accessible, we’d love to hear from you.

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