Senior AI Software Engineer (Agentic Systems & LLM Infrastructure)

Company Overview

Function was founded with a singular focus: empower you to live 100 healthy years. We’re doing that by using the best available technology to make sure people don't suffer or die a preventable death. Function has been recognized as one of Fast Company’s Most Innovative Companies of 2024, and is venture-backed by Andreessen Horowitz (a16z). Hundreds of thousands of members have joined Function to take control of their health. We are growing our team and seeking out world-class talent that deeply believes in our mission to positively impact global health, has a relentless bias toward action and a growth mindset. Function fosters a collaborative and dynamic environment, where every day we are building the future.

Role Overview

As a Senior AI Software Engineer, you will own the design and development of end-to-end AI systems, spanning backend infrastructure, model orchestration, and production-grade deployment. You’ll work closely with product, data, and infrastructure teams to integrate LLMs, agentic frameworks (LangGraph, LangChain, AutoGen), computer vision models, and vector-based reasoning systems into consumer-facing and internal tools. This role is highly technical, hands-on, and requires both deep systems expertise and practical AI application skills. If you’re a high-ownership engineer excited to ship AI-powered products at scale, this is your opportunity to make a real impact.

Key Responsibilities

• Design, build, and scale distributed backend systems that power LLMs, agents, and AI infrastructure.
• Integrate AI/LLM models into product systems (e.g., LangGraph, Agentic APIs, vector stores, orchestration layers).
• Develop high-reliability APIs and services for real-time AI inference, telemetry, usage metering, and monitoring.
• Own backend architecture decisions across authentication, billing, deployments, and developer platforms.
• Collaborate closely with product, infra, and research teams to translate cutting-edge AI into production systems.
• Ensure production-readiness through observability, CI/CD pipelines, and SRE-style reliability engineering.
• Drive continuous improvement, pushing for faster iteration, scalability, and throughput.
• Mentor peers and lead by example with a hands-on, high-ownership, startup-style mindset.

Must-Have Qualifications

• 5+ years of experience building production-grade backend systems in Python, Go, or similar.
• Deep experience with distributed systems, microservices, and event-driven architecture.
• Strong grasp of AI/ML infrastructure, model inference, model serving, and agentic frameworks.
• PostgreSQL, Redis, or similar data store expertise, including performance tuning and scaling.
• Familiarity with vector databases, embeddings, and LLM-specific storage/search systems.
• Experience deploying in cloud-native environments (AWS, GCP) using Kubernetes, Terraform, Docker.
• Proficiency with API design, backend frameworks (e.g., FastAPI, Flask), and load balancing.
• Hands-on experience with telemetry, monitoring, logging, and production issue triage.
• Understanding of CI/CD workflows, developer tooling, and test automation at scale.
• Ability to work in fast-paced, early-stage environments, making tradeoffs and shipping quickly.
• Strong communication skills: clear, concise, and collaborative—even when disagreeing.
• Bias for action: you’re a scrappy problem solver who thrives in ambiguity.

Nice-to-Have Qualifications

• Experience with LangChain, LangGraph, AutoGen, OpenAI APIs, or other agent-based orchestration frameworks.
• Familiarity with computer vision models and multimodal AI systems.
• Background in health tech, regulated data systems (HIPAA compliance), or medical data pipelines.
• Experience building AI-powered consumer applications with personalization and real-time inference.
• Exposure to reinforcement learning, retrieval-augmented generation (RAG), or long-term memory agents.
• Motivated by a mission-driven product, with excitement for being part of explosive growth.
• Background in competitive sports, military, or other high-intensity, high-throughput environments where resilience and ownership are key.

Why Join Us

• Work on cutting-edge AI products that directly help people improve their health.
• Build agentic systems from the ground up, influencing technical strategy and architecture.
• Join a fast-moving, high-ownership team, with significant autonomy and impact.
• Competitive compensation, equity, and benefits in a rapidly scaling health tech company.

At Function, we celebrate diversity and are committed to building a diverse and inclusive workforce. As an equal opportunity employer, we do not discriminate on the basis of race, color, gender identity, ancestry, religion, age, sexual orientation, national origin, disability, marital status, Veteran status, or any other occupationally irrelevant criteria.

Join the Function Health team and become a part of our mission to build a healthier future for all. Discover more about us and how we're changing the face of healthcare at Function Health.

Important Notice: Legitimate communication from the Function Health team will always come from an email address ending in @functionhealth.com. Function Health will never request personal information such as banking details or payment during the hiring process. Please be cautious of communications or job offers that come from other email domains, instant messaging platforms, or unsolicited calls. If you ever have doubts about the legitimacy of a communication, please reach out to us directly at talent@functionhealth.com.