Application Engineer II - Hosted Integrations

About the Role

Mollie is one of the fastest-growing Fintech in Europe, and we are facing many exciting technical and organisational challenges. Serving more than 250,000 businesses across the continent, we aim to cut through financial bureaucracy that hinders great ideas from growing. Our belief is that accepting payments, driving revenue, accessing capital, and managing money should be seamless for every business.

The Hosted Integrations team builds the essential connections between Mollie and major e-commerce platforms like Shopify, Wix, Lightspeed, and Mirakl. As an Application Engineer II on this team, you will design, build, and migrate the services that directly empower thousands of businesses to seamlessly accept payments and grow their operations. We're looking for an engineer with a product mindset who excels at solving complex problems in a distributed systems environment.

What You'll Do

• Build and scale robust backend services and APIs using Java.

• Migrate legacy integrations to our modern, event-driven microservices platform.

• Own the development of new features from technical design to deployment.

• Collaborate with Product and other engineers to define and deliver high-impact solutions.

• Improve the reliability and performance of our distributed systems.

Your Profile

• Required: 3+ years of software development experience.

• Required: Strong proficiency in Java.

• Proven experience with distributed systems, microservices, and Hexagonal Architecture.

• Skilled with relational databases (MySQL/PostgreSQL) and caching (Redis).

• Experience with asynchronous communication and event-driven patterns.

• You are product-aware and focused on user impact.

Nice to Haves

• Some experience with frontend development using ReactJS, TypeScript, HTML, and CSS. The ability to contribute across the stack is a significant plus.

• Familiarity with Spring Boot or PHP.

• Cloud experience (GCP/AWS).

• Knowledge of functional programming principles.

• Background in payments or marketplace platforms.

Our Tech Stack

• Backend: Java, Spring Boot, PHP

• Frontend: ReactJS, TypeScript

• Database: MySQL, Redis

• Infrastructure: GCP

Architecture: Microservices, Event-Driven, Hexagonal Architecture