Senior Backend Engineer

The French Sourcer; Paris; Sur place; EUR 85 000 - 120 000; Plein temps

Avantages offerts par ce poste

Health insurance

meal vouchers

profit-sharing

hybrid working policy

Résumé du poste

The French Sourcer in Paris is seeking a Senior Backend Engineer to design and build scalable backend services for a high-traffic SaaS platform. You will work on APIs used by customer-facing products and internal systems, and help decompose a monolith into independently scalable services.

You’ll optimize performance, model relational data, write tests, review code, and collaborate with product managers, frontend engineers, and the platform team to improve deployment, observability, and

Qualifications

• 5+ years of experience developing backend applications.
• 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.
• Professional French and English.

Responsabilités

• 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

Connaissances

Backend development

Java

Kotlin

C#

Node.js

API design

Relational DB

Distributed systems

CI/CD

Testing

French/English

Outils

Containers

Cloud environments

CI/CD pipelines

Description du poste

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/CDPractical 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
• hybrid working policy.

Languages: Native or bilingual French and professional English.