Jobs in Nancy, France

At sunday, we’re transforming the dining experience with fast, seamless payments. No more waiting for the bill — with one scan, guests pay, tip, and leave. We're creating a world where time is better spent enjoying the moment. We’re a growing team of bold thinkers, builders, and creators, working across Europe and North America to bring better hospitality to life.

We’re looking for a Senior Back-End Engineer to help elevate how we build guest-facing products at sunday. This isn’t just about writing great code — it’s about shaping how the back-end is done across the company. You’ll play a critical role in structuring projects, setting engineering standards, mentoring teammates, and driving architectural clarity. If you care about quality, collaboration, and creating systems that scale, we want to hear from you.

• Drive the unification and evolution of features across our apps to deliver a cohesive and high-quality user experience
• Lead architectural decisions and long-term thinking around scalability, performance, and maintainability
• Share your thinking in architecture forums and document decisions through Architecture Decision Records (ADRs)
• Raise the bar on code quality through testing, documentation, and shared tooling
• Partner closely with product and design teams to deliver value through fast, focused iterations
• Design and maintain core ledger systems to accurately record and reconcile financial transactions
• Implement accounting and payment workflows that ensure compliance with financial regulations
• Collaborate with finance and operations teams to translate business rules into scalable technical solutions
• Ensure high reliability and auditability of financial data across distributed systems

• You are laser-focused on impact. You don’t just ship code — you ship results. You thrive in fast-paced, moving environments. You’re driven by outcomes, not output, and you know that progress is better than perfection.
• You take end-to-end ownership — from shaping the problem with product and business teams, to delivering clean solutions, to making sure everything runs smoothly in production. You care just as much about the “why” as the “how”, and you’re comfortable stepping into early-stage product conversations, customer feedback loops.
• You’re relentlessly execution-oriented, adaptable, and always focused on delivering value.
• As a senior engineer, you understand that your impact goes beyond your own code. You actively mentor others, foster good engineering practices, and lead by example. You influence across teams, elevate the technical bar, and help align teams on architectural decisions.
• You have a strong proficiency in Java, Kotlin, Spring and scalable back-end architecture patterns
• You're fluent in testing approaches, performance optimization, and modern tooling
• You have experience working with ledgers, double-entry accounting models, and transaction reconciliation
• You understand financial compliance, audit requirements, and secure handling of sensitive financial data
• You are able to translate business and product goals into maintainable technical solutions
• You are a clear communicator, both written and verbal — especially in asynchronous contexts
• You're able to design and challenge API contracts for clarity, completeness, and long-term evolution
• You offer mentoring and share good design practices with your colleagues

You don’t need to be an expert in everything, but the more of these boxes you tick, the better:

• Awareness of security concerns and how to address them proactively
• Experience building resilient interfaces on top of distributed systems (graceful degradation, loading states, error handling)
• Familiarity with observability (logs, traces, metrics) and performance monitoring tools
• Basic understanding of edge deployments
• Hands-on experience integrating with payment processors, banking APIs, or accounting platforms
• Knowledge of reconciliation processes, fraud prevention techniques, and transaction anomaly detection

sunday is growing fast — and with that comes complexity. We’re scaling across products, markets, and teams. This role is about helping us bring clarity to that complexity. You’ll play a key part in shaping the way we build and scale at sunday, making sure our experiences are fast, delightful, and resilient — no matter how big we get.

• Competitive salary and equity
• Remote-first friendly culture with flexible working hours

• The chance to build products used by millions across the globe
• 100% health coverage for you and your children
• Free vacation policy
• Opportunity for significant impact in shaping innovative product development within a high-growth environment

Thank you for taking the time to apply, and looking forward to getting to know you!

sunday is an equal opportunity employer and does not discriminate and all qualified applicants will receive consideration for employment without regard to race, creed, color, sex, affectional or sexual orientation, gender identity or expression, gender, ethnicity, religion, national origin, ancestry, nationality, age, disability, marital status, veteran status, genetic information, or on any other basis prohibited by law (except where an attribute is a bona fide occupational qualification).