Senior Software Engineer, Payments

Lemonway is a licensed payment institution at the heart of Europe’s new digital economy.

We secure payments for crowdfunding platforms, the collaborative economy, marketplaces and online retailers, with a strong commitment to fighting fraud and protecting funds.

Regulated by the ACPR and benefiting from the European passport in 29 countries, Lemonway is based in Paris and Hamburg and brings together 150 multicultural and committed Lemonheroes.

More than 400 marketplaces trust us. We manage 1.4 million user wallets and have raised €50 million from Breega, Speedinvest and Toscafund.

Profitable for the past four years and growing by 25% in 2025, Lemonway aims to remain one of Europe’s leading payment providers through healthy and sustainable growth.

About the role

We are looking for a Senior Software Engineer for the Payments Tribe, a critical part of our platform powering the payment experience across all channels. You will report to the Engineering Manager of the Tribe, and work closely with 8 engineers across 2 squads (Core banking, Payments).

You will architect, design, and drive the enhancement of our platform by specifying, implementing, testing, monitoring and troubleshooting the services provided to our customers, working across payment APIs, processing, reconciliation, and core banking systems.

This role combines technical craftsmanship, teamwork and product mindset for a Tribe that is central to both current and future projects for Lemonway. You will play a pivotal role in designing and delivering our next-generation card payment stack for acquiring and issuing, as well as our cash management platform.

Your responsibilities

Technical craftsmanship

• Design and deliver scalable, complex features that can evolve with the right trade-off between code quality and time spent

• Lead code and architecture reviews, actively enforcing and shaping the Tribe’s best practices and architectural decisions

• Drive continuous improvement: stay updated on the latest ecosystem trends, experiment with new patterns, and actively mentors peers to elevate the Tribe’s engineering standards

Domain ownership

• Take strong ownership of the products we develop, and contribute to all parts of the development cycle from specifying to solving issues that our clients are facing in production

• Deep dive into our complex payment ecosystem. Ask tough questions, challenge the status quo, and leverage your architectural expertise together with domain knowledge to build resilient solutions

• Understand the “why” behind the “what”: bridge the gap between technical implementation and business value, ensuring our payment flows directly drive Lemonway’s operational success and client satisfaction

Team player

• Collaborate closely with software, QA and infrastructure engineers to solve technical challenges, as well as product managers for feature development

• Act as a technical communicator: translate complex architectural decisions into clear, actionable insights for both technical and non-technical stakeholders

• Participate actively in our hybrid setup with people at the office, at home, and nearshore

• Strike the right balance between independent problem-solving and guiding teammates, whilst being solutions oriented in your approach

Your qualifications

• You have 5 years of experience in software engineering, building robust and scalable applications

• You have deep architectural knowledge and proven hands-on experience with Domain-Driven Design (DDD), Hexagonal architecture, Event-Driven Architecture, and Command Query Responsibility Segregation (CQRS)

• You have strong expertise in relational databases and a proven track record of designing, building, and operating micro services-based architectures

• You possess excellent communication skills, enabling you to drive technical consensus and collaborate effectively across teams

• You are familiar with our technical stack based on modern .NET (C#), MS SQL, RabbitMQ, Docker, and Kubernetes

• You have practical experience in building CI/CD pipelines and using Terraform for Infrastructure as Code (IaC)

• You are fluent in French and you are comfortable working in English, which is a strong asset given our international environment

• (Nice to have) You actively leverage AI tools in your ways of working

• (Nice to have) Knowledge of payments processing in a regulated environment
  

If you do not meet all the requirements, but believe you can succeed in this role, we encourage you to apply.

What we offer

• Offices in Sentier, at the heart of Paris

• A hybrid way of working with 2 days of WFH/week

• Meal vouchers through Swile

• Alan complementary health care plan

• 50% Reimbursement of your monthly transportation pass Navigo/Vélib

• Access to Gymlib for a healthier lifestyle that works for you

• Holiday and RTT plan aligned with the Syntec agreement