Senior AI Mobile Engineer — LLM, RAG & Python Systems

Zenith System Solutions; St. Louis (MO); On-site; USD 140,000 - 210,000; Full time

Job summary

Zenith System Solutions seeks a senior Python engineer to advance production-grade AI platforms. You will design and implement end-to-end LLM solutions, focusing on LangChain-based workflows, RAG pipelines and robust API layers with FastAPI.

Qualifications include 10+ years in Python, hands-on LLM development, and strong system design experience in scalable microservices and modern DevOps ecosystems.

Qualifications

• 10+ years of software development with Python production experience.
• 2+ years hands-on LLM development using LangChain, LangGraph or equivalents.
• Experience with RAG pipelines: embeddings, vector search, re-ranking, answer generation.
• Familiar with LLM APIs: OpenAI Chat Completions, Responses API, streaming, tool calling.
• Proficient in Async Python (asyncio, httpx, FastAPI).
• Strong prompt engineering: system prompts, few-shot, structured JSON output.
• Circuit breaker patterns, retry logic for resilient services.
• PostgreSQL with async ORMs (SQLAlchemy async / Alembic).
• Git, CI/CD, Docker, Kubernetes basics.
• Strong system design: microservices, distributed systems, API design.

Skills

LLM development

RAG pipelines

LLM APIs

Async Python

Prompt engineering

Resilient design

PostgreSQL async

System design

Tools

Docker

Kubernetes

Git

CI/CD

SQLAlchemy async

Alembic

Job description

Zenith System Solutions seeks a senior Python engineer to advance production-grade AI platforms. You will design and implement end-to-end LLM solutions, focusing on LangChain-based workflows, RAG pipelines and robust API layers with FastAPI.

Qualifications include 10+ years in Python, hands-on LLM development, and strong system design experience in scalable microservices and modern DevOps ecosystems.