Software Engineer (AI Backend Services)
- Europe - Any Pfizer Site
- France - Rives de Paris

Our Purpose
Our Values
Pfizer Digital
Benefits
The AI Backend Python Engineer (SE III) will design, develop, and own backend systems and components that power generative AI applications and large language model (LLM) integrations. This role focuses on independently architecting and delivering scalable, secure, and high-performance services using Python, FastAPI, and AWS cloud infrastructure, while mentoring junior engineers.
KEY RESPONSIBILITIES
- Design and implement Python-based backend services (on FastAPI) for AI workloads, including LLM integration and generative AI pipelines
- Own end-to-end design and delivery of APIs and microservices for model serving, inference, and orchestration of AI agents
- Architect and maintain AWS-based infrastructure for AI workloads (e.g., Lambda, EKS) with focus on scalability and reliability
- Make independent technical decisions for component-level architecture and design patterns
- Lead integration efforts for LLMs and generative AI models into production systems using LangChain, Langfuse, and litellm
- Establish monitoring, logging, and observability best practices for AI backend services
- Optimize backend performance for large-scale AI applications
- Mentor Software Engineer II team members through code reviews and technical guidance
- Collaborate with cross-functional teams and influence technical direction across multiple projects
BASIC QUALIFICATIONS
- 4-7 years of professional software engineering experience with strong backend focus
- Expert-level proficiency in Python for backend development in production environments
- Solid understanding of LLMs, generative AI concepts, and modern AI frameworks (e.g., LangChain, litellm, Langfuse)
- Proven experience designing and building scalable systems on AWS (Lambda, API Gateway, EKS)
- Deep knowledge of microservices architecture, API design, and distributed systems
- Strong experience with containerization (Docker/Kubernetes) and orchestration
- Demonstrated ability to own technical components and make independent architectural decisions
- Bachelor's or Master's degree in Computer Science, Engineering, or related field, or equivalent practical experience
PREFERRED QUALIFICATIONS
- Extensive experience building and scaling APIs and backend systems for AI/ML workloads in production
- Deep expertise with FastAPI and asynchronous Python programming
- Experience architecting event-driven systems for AI applications
- Track record of mentoring engineers and conducting effective code reviews
- Strong understanding of system design patterns and trade-offs
- Experience with infrastructure-as-code (Terraform, CloudFormation)
- Knowledge of model deployment strategies and MLOps practices
- Proven ability to drive technical initiatives and influence engineering culture
- Excellent communication skills and experience working across teams
Work assignment location : Remote
Pfizer is an equal opportunity employer and complies with all applicable equal employment opportunity legislation in each jurisdiction in which it operates.
Égalité des chances & Emploi
Nous croyons que des équipes diversifiées et inclusives sont essentielles à la réussite d'une entreprise. En tant qu'employeur, Pfizer s'engage à valoriser la diversité et l’inclusion sous toutes ses formes. Cette diversité se reflète également à travers les patients et les communautés que nous servons. Ensemble, continuons à bâtir une culture qui encourage, soutient et responsabilise nos employés.
Handicap & Inclusion
Notre mission est de libérer le potentiel de nos collaborateurs et nous sommes fiers d'être un employeur inclusif pour les personnes handicapées, garantissant ainsi l'égalité des chances en matière d'emploi pour tous les candidats. Nous vous encourageons à donner le meilleur de vous-même en sachant que nous apporterons tous les ajustements raisonnables pour soutenir votre candidature et votre carrière future. Votre expérience avec Pfizer commence ici !
Information & Business TechBreakthroughs that change patients’ lives
Research confirms what intuition tells us: that purpose-driven companies perform better, are more innovative, attract and retain the best people, and know how to unleash the power of those people. Pfizer’s purpose—Breakthroughs that change patients' lives—fuels everything we do and reflects our passion for building on our legacy as one of the greatest contributors of good to the world.
Each word in our purpose has meaning and reflects the value we strive to bring to patients and society:
“Breakthroughs” - These are the innovations, scientific and commercial, that we seek to deliver every day. All colleagues, regardless of role, level or location, strive for breakthroughs every day.
“Change” - We want to do more than simply improve patients’ medical conditions; we want to dramatically change their lives for the better.
“Patients’ lives” - We consider not only patients, but everyone they touch—including their families, caregivers, and friends—and everything they love to do. It’s an intentionally holistic view.
Our purpose ensures that patients remain at the center of all we do. We live our purpose by sourcing the best science in the world; partnering with others in the healthcare system to improve access to our medicines; using digital technologies to enhance our drug discovery and development, as well as patient outcomes; and leading the conversation to advocate for pro-innovation/pro-patient policies.
Every decision we make and every action we take is done with the patient in mind—and to nurture an environment where breakthroughs can thrive.
Our Values
To fully realize Pfizer’s purpose, we have established a clear set of expectations regarding “what” we need to achieve for patients and “how” we will go about achieving those goals.
The “how” is represented by four simple, powerful values—courage, excellence, equity, and joy—that define our company and our culture.
Courage: Breakthroughs start by challenging convention, especially in the face of uncertainty or adversity. This happens when we think big, speak up, and are decisive.
Excellence: We can only change patients’ lives when we perform at our best together. This happens when we focus on what matters, agree who does what, and measure our outcomes.
Equity: We believe that every person deserves to be seen, heard, and cared for. This happens when we are inclusive, act with integrity, and reduce healthcare disparities.
Joy: We give ourselves to our work, but it also gives to us. We find joy when we take pride, recognize one another, and have fun.
Pfizer Digital
Pfizer Digital takes immense pride in being at the forefront of innovation, harnessing cutting-edge smart technology that profoundly impacts the lives of our patients.
With the transformative potential of digital solutions, we revolutionize how we discover, develop, and deliver medicines, enabling us to achieve breakthroughs faster and more efficiently.
By streamlining and automating transactional processes, we create valuable time and resources, empowering our talented team to focus on meaningful work that truly makes a difference in healthcare and beyond.
Benefits at Pfizer
Pfizer offers competitive compensation and benefits programs designed to meet the diverse needs of our colleagues. Our Pay for Performance Philosophy and Practices reward colleagues based on the contributions they make to our business.
Our Competitive Benefits Programs help our colleagues by:
- Promoting Health and Wellness to help colleagues maintain and improve their physical and mental wellbeing. Pfizer offerings include health and disability insurance, preventative health programs, medical screenings, free or reduced-cost vaccinations, discounts on Pfizer products, mental health support, nutrition and fitness counseling and more.
- Strengthening Colleagues’ Financial Security by providing company contributions to retirement plans, life insurance and financial planning education to help colleagues achieve their financial goals.
- Providing Benefits and Time off for the Moments that Matter to ensure Pfizer colleagues have the time away from the office to recharge, recover and return to work as the best version of themselves. Vacation, Holiday time and Sick time are just the beginning, with a 12 week parental leave policy for both parents of a new born, 10 day of caregiver leave for those times when your family needs you whether it’s a child, spouse or parent, bereavement leave, and additional country-specific programs.
- And so much more, depending on your country and site, Pfizer offers childcare facilities or discount programs, on-site health and/or fitness centers, movement and mindfulness solutions, “Log in for your Day” work flexibility and so much more.
For U.S. based jobs, view an overview of Pfizer’s U.S. benefits program (opens in a new window)
