Principal Machine Learning Engineer
- Compensation
- $264K–$363K / yr
- Location
- Office Hub - Santa Barbara
- Work setup
- Hybrid
- Seniority
- Principal
- Employment
- Full time
- Experience
- 10+ years
- Category
- Ml / AI
- Posted
Skills
Must have
- Systems thinker: You think in terms of systems, platforms, and long-term leverage, not just features.
- Production builder: You've built and scaled ML/AI systems in production with meaningful business impact.
- Ambiguity: You operate effectively in high ambiguity, turning unclear problems into a clear direction.
- Influence: You've led or influenced large, cross-team technical initiatives.
- Originality: You introduce new ideas, architectures, or paradigms — not just implement existing ones.
- Owner-operator: You bring a founder / owner-operator mindset: you take ownership, act with urgency, and focus on outcomes.
- Pace: You have a strong desire to move fast and deliver impact, while maintaining sound engineering judgment.
- Collaboration: You are humble, collaborative, and low-ego, and you elevate those around you.
- Sustainability: You value work-life balance as a foundation for sustained high performance.
- Vertical conviction: You bring genuine interest in winning a specific industry vertical (real estate) rather than chasing horizontal AI hype.
- Master's or Ph.D. in Computer Science, Machine Learning, or a related field (required).
- 10+ years of experience building software systems, with significant focus on ML/AI (or equivalent impact).
- Combined academic and industry track record: Published research and shipped production systems.
- Deep ML expertise: Traditional Machine Learning, Deep Learning, and Generative AI / LLMs (prompting, fine-tuning, RAG, agents, tool and skills use).
- LLM post-training: Direct, hands-on experience with LLM post-training — SFT, RLHF, DPO, and/or RL — at non-trivial scale.
- Full ML lifecycle: Strong understanding of data extraction, model training, evaluation, deployment, and integration into production software.
- Core stack: Expert in Python, PyTorch, NumPy, AWS, Docker, SQL, embeddings, and RAG.
- Agent tooling: Experience with LangChain, LangGraph, and LLM observability tools (LangSmith).
- Production ML at scale: Experience designing and operating production-grade ML systems at scale.
- Ontology & knowledge graphs: Applied experience with ontology-driven systems, knowledge graphs, or semantic layers used to model business domains for AI systems.
- AI-native engineering: Proficiency with AI coding tools and workflows (e.g., Copilot, ChatGPT, code generation tools).
Nice to have
- Reinforcement Learning depth: 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.).
Full description
AppFolio is more than a company. We’re a community of dreamers, big thinkers, problem solvers, active listeners, and multipliers. At every opportunity, we set the pace while delivering innovation built to carry real estate into the future. One in which every experience feels effortless, yet meaningful. Where customers are empowered to take on any opportunity. We show up as one team, connected by our values to be a force for good. Because together, we have the power to create extraordinary outcomes for our customers, our communities, and ourselves.
Realm-X is AppFolio's AI-native platform powering this transformation. It enables a new generation of intelligent capabilities across our products, including Realm-X Assistant (copilot), Flows (AI Agentic workflows) and Performers (autonomous AI Agents). Realm-X serves as both a foundation for internal teams to build and scale AI-powered products, and a core layer delivering intelligent, high-impact experiences directly to our customers.
At its core, Realm-X is built on a structured domain ontology and a set of shared business primitives—such as transactions, actions, reports, metrics, and skills—that enable AI systems to deeply understand and operate across the full context of property management workflows. This foundation allows us to build context-aware, action-oriented AI systems that go beyond simple assistance to power real automation and decision-making.
Who We Are Looking For
We're seeking a Principal Machine Learning Engineer to help define and lead the next generation of AI systems within Realm-X, and to drive AppFolio's long-term autonomous Real Estate Performance Management (RPM) platform — autonomous AI agents that can deliver property management performance.
This is a company-impact role. You will own mission-critical AI capabilities, shape long-term technical strategy, and act as a technical visionary and advisor across teams and leadership.
You'll operate at the intersection of traditional machine learning, deep learning, and generative AI, building systems that go beyond AI assistance into execution, automation, and optimization.
This role is for someone who doesn't just build systems — but redefines how they should be built.
Your Impact
- Architect & Lead: Help define the technical vision and architecture for AI systems across Realm-X in partnership with senior leadership.
- Scale Intelligent AI Agents: Design and deploy advanced AI Agentic systems that combine reasoning, planning, and execution, including multi-agent orchestration across specialist agents (e.g., maintenance, leasing, accounting, collections).