Staff Machine Learning Engineer (San Diego)

DescriptionHi, We're AppFolioWe're innovators, changemakers, and collaborators. We're more than just a software company — we're building the AI-native platform where the real estate industry comes to do business. We're transforming Property Management; how property managers operate, how residents live, and how intelligence flows across an entire industry.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 ForWe're hiring a Staff Machine Learning Engineer to help move forward the ML platform that every AI initiative at AppFolio depends on — training, fine-tuning, inference, RAG, evaluation, and cost. You'll keep our AI cloud always-on, observable, and economical, while staying close enough to applications to influence model and agent design.This role works at the intersection of ML infrastructure, applied AI, and cost discipline. You'll partner closely with our Voice & Agents and Research ML engineers to harden their prototypes into production systems, and help move forward the platform layer that lets Realm-X scale across AppFolio's entire customer base.Your ImpactML Platform: Design and operate AppFolio's ML infrastructure on AWS — ECS, SageMaker, GPU fleets, model serving, autoscaling, and cost controls.Drive AI Cost Discipline: Optimize cost across all AI applications — provider routing, caching, batch vs. real-time, model size selection, and inference economics.Multi-Provider Reliability: Maintain reliable, multi-provider LLM access across Google, OpenAI, and Anthropic with sensible fallbacks and abstractions.Training & Fine-Tuning Stack: Build the training and fine-tuning stack for Small Language Models, including data pipelines, GPU orchestration, and evaluation.Productionize Research: Partner with Voice & Agents and Research ML engineers to harden their prototypes into production systems with SLOs, on-call rotations, and observability.AI Safety & Guardrails: Operate AppFolio's AI safety and authorization layer — guardrails on AWS, scoped tool permissions, and human-in-the-loop gates for autonomous agent actions.QualificationsSystems thinker: You think in terms of platforms and long-term leverage, not just features.Production builder: You've built and scaled ML infrastructure in production with meaningful business impact.Ambiguity: You operate effectively in high ambiguity, turning unclear infra problems into clear direction.Owner-operator: You take ownership with a founder/owner-operator mindset, 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.Reliability mindset: You treat ML infra like any other production system — SLOs, on-call, observability, postmortems.Must HaveML infra at scale: Has built and operated production ML infrastructure on AWS — ECS, SageMaker, GPUs, autoscaling, and cost controls.Inference platforms: Production experience with model serving for both LLMs and custom models; understands quantization, batching, and routing.Provider breadth: Direct experience integrating with Google (Vertex / Gemini), OpenAI, and Anthropic APIs in production.Training capability: Has trained or fine-tuned language models end-to-end; comfortable with deep learning, evaluation, and inference.Cloud-native engineering: Strong Python, Docker, dependency management, and CI/CD for AI workloads.RAG & agents: Working knowledge of LangChain / LangGraph and modern RAG patterns over structured and unstructured data.Cost optimization: Demonstrated experience reducing unit cost of AI workloads without regressing quality or latency.AI safety & authorization: Hands-on experience operating AI guardrails, scoped tool permissions, and authorization layers for production AI systems.Nice to HaveExperience training Small Language Models for production use.GPU performance tuning (vLLM, TensorRT, Triton, or similar).Prior Staff-level role at a company with a significant AI infra footprint.Experience with ontology-driven systems or knowledge graphs supporting AI applications.Contributions to open-source ML infrastructure or LLM tooling.LocationFind out more about our locations by visiting our site. Compensation & BenefitsThe compensation that we reasonably expect to pay for this role is: $200,000 - 250,000 base pay. The actual compensation for this role will be determined by a variety of factors, including but not limited to the candidate’s skills, education, experience, and internal equity.Please note that compensation is just one aspect of a comprehensive Total Rewards package. The compensation range listed here does not include additional benefits or any discretionary bonuses you may be eligible for based on your role and/or employment type.Regular full-time employees are eligible for benefits - see here.style=color:#ffffff;>#LI-KB1About AppFolioAppFolio is the technology leader powering the future of the real estate industry. Our innovative platform and trusted partnership enable our customers to connect communities, increase operational efficiency, and grow their business. For more information about AppFolio, visit appfolio.com. Why AppFolioGrow | We enable a culture of high performance, where delivering results is recognized by opportunities for growth and compelling total rewards. Our challenging and meaningful work drive the growth of our business, and ourselves.Learn | We partner with you to realize your potential by investing in you from the start. We're cultivating a team of big thinkers through coaching and mentorship with our best-in-class leaders, and giving you the time and tools to develop your skills.Impact | We are creating a world where living in, investing in, managing, and supporting communities feels magical and effortless, freeing people to thrive. We do this by innovating with purpose while cultivating a culture of impact. We learn as much from each other as we do our customers and our communities.Connect | We excel at hybrid work by fostering an environment that feels flexible, personal and connected, no matter where we are. We create space to fuel innovation and collaboration, and we come together to celebrate, connect, and succeed.Paddle as One.Learn more at appfolio.com/company/careersStatement of Equal OpportunityAt AppFolio, we value diversity in backgrounds and perspectives and depend on it to drive our innovative culture. That’s why we’re a proud Equal Opportunity Employer, and we believe that our products, our teams, and our business are stronger because of it. This means that no matter what race, color, religion, sex, sexual orientation, gender identification, national origin, age, marital status, ancestry, physical or mental disability, or veteran status, you’re always welcome at AppFolio.