Principal Machine Learning Engineer

AppFolio is hiring a Principal Machine Learning Engineer to define and lead AI systems for Realm-X and an autonomous Real Estate Performance Management (RPM) platform.

Responsibilities

• Define the technical vision and architecture for AI systems across Realm-X in partnership with senior leadership
• Design and deploy AI Agentic systems that combine reasoning, planning, and execution
• Deliver multi-agent orchestration across specialist agents for areas such as maintenance, leasing, accounting, and collections
• Establish platform primitives and abstractions for context-aware, action-oriented automation
• Raise standards across end-to-end ML systems: data collection, training, evaluation, deployment, and inference infrastructure
• Architect and build scalable multi-modal and real-time AI applications with high-quality deployment practices
• Lead AppFolio’s transition toward autonomous property management operations using existing LLMs today, while instrumenting proprietary data collection for future training workflows
• Enable selective training, fine-tuning, and RL optimization for open source LLMs and SLMs in the RPM domain to optimize performance, latency, and cost
• Build data and feedback loops to enable Reinforcement Learning over agent action policies in partially observable, high-stakes property management

Requirements

• Master’s or Ph.D. in Computer Science, Machine Learning, or a related field
• 10+ years building software systems with significant focus on ML/AI (or equivalent impact)
• Published research and shipped production systems
• Experience with traditional ML, deep learning, and generative AI / LLMs including prompting, fine-tuning, RAG, agents, and tool and skills use
• Hands-on experience with LLM post-training such as SFT, RLHF, DPO, and/or RL at non-trivial scale
• Strong grasp of data extraction, model training, evaluation, deployment, and integration into production software
• Expertise in Python, PyTorch, NumPy, AWS, Docker, SQL, embeddings, and RAG
• Experience with LangChain, LangGraph, and LLM observability tools such as LangSmith
• Experience designing and operating production-grade ML systems at scale
• Applied experience with ontology-driven systems, knowledge graphs, or semantic layers to model business domains for AI
• Proficiency with AI coding tools and workflows, e.g., Copilot and ChatGPT, including code generation tools

Technologies

• Python, PyTorch, NumPy
• AWS, Docker, SQL
• Embeddings, RAG
• LangChain, LangGraph, LangSmith
• Copilot, ChatGPT
• SFT, RLHF, DPO
• LLMs, SLMs

Nice to Have

• Deep RL expertise applied to sequential decision-making under partial observability
• Experience designing evaluation and benchmarking systems for AI
• Background in distributed systems and real-time architectures
• Experience building platforms used by multiple engineering teams
• Contributions to industry thought leadership (publications, talks, open source, etc.)

Benefits

• Regular full-time employees are eligible for benefits
• Compensation range: $264,000 - $363,000 base pay
• Additional benefits or discretionary bonuses may be eligible based on role and/or employment type

Location

• Goleta, CA (onsite)
• Find out more about locations by visiting AppFolio’s site
• All late-stage candidates complete an in-person meeting with an AppFolian as part of the hiring process