Senior Backend Engineer

Build the services behind a product used every day, while helping the platform scale beyond its original architecture.

Senior Backend Engineer - Paris

Paris, France · Permanent · Hybrid

What you'd actually work on

• Designing and developing backend services for a high-traffic SaaS platform
• Building APIs used by customer-facing products and internal systems
• Breaking down parts of an existing monolith into clearly defined services
• Improving application performance, reliability, and scalability
• Designing relational data models and optimising critical queries
• Writing automated unit, integration, and API tests
• Reviewing code and contributing to shared engineering standards
• Investigating production issues across applications, databases, and infrastructure
• Working with product managers and frontend engineers to define technical solutions
• Improving deployment and release processes with the platform team
• Contributing to architecture decisions and technical documentation

Where it gets technically interesting

• Evolving a mature platform without interrupting ongoing product delivery
• Deciding which components should become independent services and which should remain together
• Managing data consistency and dependencies across distributed services
• Improving performance on endpoints operating under sustained production load
• Introducing stronger testing and observability into critical legacy components
• Balancing immediate product needs with longer-term architectural improvements

What we're looking for

• 5+ years of experience developing backend applications
• Strong experience with Java, Kotlin, C#, Node.js, or a comparable backend technology
• Experience designing and maintaining production APIs
• Good knowledge of relational databases and data modelling
• Understanding of distributed systems and asynchronous communication
• Experience with automated testing, code reviews, and CI/CD
• Practical knowledge of containers and cloud environments
• Ability to investigate production issues across several technical layers
• Confidence working with product, frontend, and platform teams
• Professional French and English

The company

A European SaaS company serving several thousand business customers. The platform is expanding across new products and markets, creating a need to modernise parts of the architecture while continuing to deliver new functionality.

Health insurance, meal vouchers, profit-sharing, and a hybrid working policy.

Languages: Native or bilingual French and professional English.

A search run by The French Sourcer, recruitment built for technical teams.