At Mollie, we believe in the power of small businesses. With our payment solutions, we empower entrepreneurs to grow smarter, faster, and more efficiently. We strive for a world in which people can achieve more, earn more, and realize their dreams. We are one of the fastest-growing payment processors within the European Union and are constantly looking for new talent to join our teams across Europe.

Mollie was founded in 2004 and in June 2021, raised €665 million in a Series C funding round, bringing our valuation to €5.9 billion—making us one of the largest privately funded fintechs in Europe. In 2023, Mollie reached profitability. Over 200,000 businesses trust Mollie to handle their payments and financial services. We are now establishing a new team and office in Lisbon, and we are working hard to further expand across Europe.

About the Position

Introduction

We are looking for a Senior Back-End Engineer to join the Mollie Wallet squad. The Mollie Wallet team is responsible for managing merchants’ funds and their digital wallets, including processing incoming and outgoing payments, ensuring the reconciliation of funds, and handling balances, payouts, and other financial movements. If you’re a skilled backend engineer with a keen interest in payments, financial technology, and building robust, scalable systems in a fast-paced, high-growth environment, we’d love to hear from you.

Responsibilities

As a Senior Back-End Engineer in the Mollie Wallet team, you will:

Architect, develop, and maintain Mollie’s core payment processing systems and financial ledgers.
Design and implement highly available and fault-tolerant solutions for managing merchant funds, ensuring accuracy and security.
Ensure the accuracy and security of all financial transactions within the Mollie Wallet system.
Collaborate across various teams to define APIs, integration points, and data models to ensure seamless end-to-end payment flows.
Mentor and coach junior engineers, fostering a culture of technical excellence and continuous improvement.
Contribute to the team's incident response and post-mortem analysis, driving continuous improvements in reliability.
Drive performance optimization and scalability initiatives.

Requirements

You thrive on solving complex technical challenges in a highly regulated and high-stakes environment.
Strong experience in building and maintaining distributed systems, particularly in the payments or financial sectors.
Expertise in a backend language (preferably PHP, but we are open to other languages like Go or Java).
Familiarity with event-driven architectures and message queuing systems (e.g., Kafka).
Working experience with relational databases (e.g., PostgreSQL, MySQL).
Familiarity with cloud platforms such as AWS, Google Cloud, or Azure.
Excellent understanding of data structures, algorithms, and software design principles.
Solid experience with unit, integration, and end-to-end testing strategies.
Strong communication, collaboration, and problem-solving skills.
Experience in working iteratively and frequently shipping new products and services to customers.

Benefits

A competitive salary and a holistic package, which includes top tier benefits: stock options, pension, yearly training budget (1,500 EUR), and more.
Flexible work arrangement—a hybrid model with a minimum of two days at the office.
A personal development plan, which includes a dedicated training budget, and a wide array of internal and industry training to help you thrive.
Free healthy lunches, snacks, and drinks at our offices.
Reimbursement of travel expenses to the office.
Quarterly hackathons and other internal events.
Table tennis, game consoles, and many more facilities at the office to help you relax and socialize.
A dedicated "Mollie Intro" program for all new Mollies, helping you to get onboarded for a smooth start.
An inclusive and diverse culture with a company-wide focus on mental and physical well-being.