Staff Software Engineer (AI Backend Services)
- Europe - Any Pfizer Site
- France - Rives de Paris
- Belgium - Zaventem
- Bulgaria - Sofia
- Romania - Bucharest
- Ireland - Dublin - Grange Castle
- Italy - Rome
- Spain - Madrid
- Greece-Thessaloniki Chortiatis
- Germany - Berlin
ROLE DESCRIPTION
The AI Backend Python Engineer (Staff) will provide technical leadership and define the architecture for backend systems that power the next generation of generative AI applications and large language model
(LLM) integrations. This role focuses on driving strategic technical direction, designing platform-level
solutions using Python, FastAPI, and AWS, and influencing engineering practices across the organization.
KEY RESPONSIBILITIES
- Define technical strategy and architecture for Python-based AI backend platforms (on FastAPI) that support LLM integration, generative AI pipelines, and AI agent orchestration
- Architect scalable, reliable, and secure systems on AWS infrastructure (Lambda, EKS) that serve as the foundation for multiple teams
- Drive technical decisions that impact organization-wide engineering practices and platform capabilities
- Design and champion AI system observability using LangChain, Langfuse, and litellm
- Establish engineering standards for monitoring, logging, observability, and operational excellence across AI backend services
- Lead cross-functional initiatives to optimize performance, security, and scalability of large-scale AI applications
- Mentor and technically guide engineers at all levels, elevating team capabilities through code reviews, architecture reviews, and technical leadership
- Identify technical debt, performance bottlenecks, and architectural limitations; drive long-term solutions
- Collaborate with engineering leadership, product, and other stakeholders to align technical strategy with business objectives
- Influence technology choices, design patterns, and best practices across the AI Software & Operations department
- Represent the team in organization-wide technical discussions and drive adoption of innovative solutions
BASIC QUALIFICATIONS
- 7+ years of professional software engineering experience with extensive backend and distributed systems expertise
- Deep expert-level proficiency in Python for building large-scale production systems
- Comprehensive understanding of LLMs, generative AI architectures, and AI infrastructure (LangChain, litellm, Langfuse, OpenAI/Anthropic APIs)
- Proven track record of architecting and delivering complex, scalable platforms on AWS
- Expert knowledge of microservices architecture, distributed systems design, and event-driven architectures
- Demonstrated experience with containerization, orchestration (Docker/Kubernetes), and cloud-native patterns
- Strong history of technical leadership, mentoring engineers, and driving organizational impact
- Bachelor's or Master's degree in Computer Science, Engineering, or related field, or equivalent practical experience
- Excellent strategic thinking and ability to balance short-term delivery with long-term architectural vision
PREFERRED QUALIFICATIONS
- Extensive experience designing and building platform-level infrastructure for AI/ML workloads at scale
- Deep expertise in FastAPI, asynchronous Python, and high-performance backend systems
- Proven track record of architecting event-driven and real-time systems for AI applications
- Experience influencing engineering culture, establishing best practices, and driving technical standards
- Strong background in MLOps, model deployment strategies, and AI system reliability
- Expertise with infrastructure-as-code, CI/CD automation, and platform engineering
- Experience working with product and business stakeholders to translate requirements into technical strategy
- History of leading cross-functional technical initiatives with measurable organizational impact
- Published technical work, open-source contributions, or recognized expertise in AI backend systems
- Exceptional communication and influence skills across all levels of the organization
Work location assignment : Remote

This role is posted in multiple locations. If you are applying for the role in an secondary job posting location where pay transparency regulations apply, your Talent Advisor will share the local pay information with you during the first interview.

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 !

Pfizer endeavors to make www.pfizer.com/careers accessible to all users. If you would like to contact us regarding the accessibility of our website or need assistance completing the application process and/or interviewing, please email [email protected]. This is to be used solely for accommodation requests with respect to the accessibility of our website, online application process and/or interviewing. Requests for any other reason will not be returned.

Pour mieux comprendre les usages autorisés et interdits de l’intelligence artificielle tout au long du processus de recrutement, nous vous invitons à consulter nos bonnes pratiques dédiées à l’utilisation de l’IA par les candidats sur Pfizer Careers.
Information & Business Tech
Breakthroughs 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.
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)