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.
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