Senior Fullstack Engineer F/H – React

Senior Fullstack Engineer F/H – React / Next.js & Ruby on Rails Job Number: R0002584Posted On: 12/11/2025Location: Boulogne-Billancourt, Île-de-France Region The Opportunity As a Fullstack Software Engineer specialized in React & Ruby on Rails, you will join the Digital Team that develops all solutions for digital products exposed to end‑users in Europe. The team is passionate about leveraging cutting‑edge technologies to deliver exceptional user experiences, and we are looking for someone who shares our enthusiasm for innovation and excellence. Responsibilities Take full ownership of product development, from initial concept through to production and ongoing maintenance. Lead the design, development, and implementation of scalable, high‑performance web applications. Develop front‑end applications using React and the Next.js framework, ensuring excellent user experience and seamless performance. Build and maintain robust backend systems using Ruby on Rails to manage application logic and data flow. Design and optimize database solutions using PostgreSQL to ensure data integrity, performance, and scalability. Implement containerization and orchestration solutions using Docker and Kubernetes, ensuring seamless deployment and scaling. Collaborate with the team to architect and integrate systems with Microsoft Azure cloud services, focusing on performance, security, and scalability. Partner closely with Product Owners, Designers, and other stakeholders to align development efforts with business goals. Mentor junior engineers, promoting best practices and fostering a culture of continuous learning and improvement. Ensure high‑quality code through code reviews, automated testing, and adherence to software development standards. Qualifications 3+ years of experience as a Fullstack Engineer or similar role, with a strong focus on product development. Expertise in React and the Next.js framework, with a deep understanding of modern front‑end development practices. Proven experience with Ruby on Rails and building robust, scalable APIs and backend systems. Strong proficiency with PostgreSQL or similar relational databases. Experience working with Docker and Kubernetes in production environments. Hands‑on experience with Microsoft Azure cloud services, including deployment, security, and monitoring. Familiarity with CI/CD pipelines and DevOps principles. Excellent problem‑solving skills with a strong attention to detail. Strong product orientation, with a passion for creating solutions that deliver real customer value. Entrepreneurial mindset: ability to take ownership of projects, think strategically, and drive impact. Strong communication skills and the ability to work cross‑functionally with both technical and non‑technical stakeholders. Fluency in English and French. Bonus Skills Experience in building and scaling SaaS or consumer‑facing products. Knowledge of other programming languages or frameworks (e.g., TypeScript, Python). Familiarity with testing frameworks and methodologies (e.g., Jest, RSpec). Total Rewards Location: Boulogne-Billancourt (Marcel Sembat) Contract: Permanent (CDI) Remote work: Up to 3 days per week Benefits: 1 RTT day per month, CAE, profit‑sharing, vacation bonus, meal vouchers, 2/3 of health insurance covered, reimbursement of up to 50% of transport costs. Recruitment Process 1st interview: Recruitment team 2nd interview: Engineering Director and Manager, Software Engineering 3rd interview: Product team Equal Employment Opportunity All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, age, sexual orientation, gender identity, national origin, citizenship status, protected veteran status, genetic information or physical or mental disability. About Catalina Catalina is a leader in shopper intelligence and precisely targeted in‑store, TV and digital media that personalizes the shopper journey. Powered by an unrivaled real‑time shopper database and AI‑optimized data science, Catalina helps retailers, CPG brands and agencies optimize every stage of media planning, execution and measurement to deliver more than $6 billion in consumer value annually. Catalina has operations in the United States, Costa Rica and Europe. To learn more, please visit www.catalina.com or follow us on LinkedIn. #J-18808-Ljbffr