AI Backend Python Engineer (Software Engineer II)

We’re in relentless pursuit of breakthroughs that change patients’ lives. We innovate every day to make the world a healthier place.

To fully realize Pfizer’s purpose – Breakthroughs that change patients’ lives – 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.

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.

Pfizer offers competitive compensation and benefits programs designed to meet the diverse needs of our colleagues.

The AI Backend Python Engineer (SE II) will develop and maintain backend systems that power generative AI applications and large language model (LLM) integrations. This role focuses on implementing features for scalable, secure, and high‑performance services using Python and AWS cloud infrastructure, with guidance from senior engineers.

KEY RESPONSIBILITIES

• Implement Python‑based backend services (on FastAPI) for AI workloads, including LLM integration and generative AI pipelines
• Develop APIs and microservices for model serving and inference with guidance from senior team members
• Build and maintain AWS‑based infrastructure components for AI workloads (e.g., Lambda, EKS)
• Write clean, well‑tested, and maintainable code following established patterns and best practices
• Integrate LLMs and generative AI models into production systems using frameworks like LangChain, Langfuse, and litellm
• Implement monitoring, logging, and observability features for assigned backend services
• Participate in code reviews and contribute to team knowledge sharing
• Debug and resolve production issues with support from senior engineers
• Collaborate with cross‑functional teams to understand requirements and deliver features

BASIC QUALIFICATIONS

• 2-4 years of professional software engineering experience or equivalent
• Strong proficiency in Python for backend development in production environments
• Understanding of LLMs, generative AI concepts, and modern AI frameworks (e.g., litellm, LangChain)
• Experience with AWS services (Lambda, API Gateway, EKS)
• Knowledge of RESTful API design and microservices architecture
• Familiarity with containerization (Docker) and version control (Git)
• Bachelor’s degree in Computer Science, Engineering, or related field, or equivalent practical experience
• Strong problem‑solving skills and attention to detail

PREFERRED QUALIFICATIONS

• Hands‑on experience building APIs for AI/ML workloads in production
• Experience with FastAPI or similar Python web frameworks
• Familiarity with Langfuse for LLM observability
• Knowledge of CI/CD practices and automated testing
• Understanding of database systems (SQL and NoSQL)
• Experience with event‑driven architectures
• Strong communication skills and ability to work collaboratively in a team environment

Work location assignment : Remote

Pfizer is an equal opportunity employer and complies with all applicable equal employment opportunity legislation in each jurisdiction in which it operates.