Sr. Machine Learning Engineer

App Folio 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.

App Folio'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.

We’re hiring a Senior Machine Learning Engineer to design and ship the next generation of voice and conversational AI agents within Realm-X. This role helps define App Folio's production voice and chat agent pipelines, working at the intersection of LLM agent frameworks, real-time voice technology, and streaming infrastructure.

You will work with Product, Voice channel, and ML Platform teams to translate cutting-edge agent and voice research into reliable, low-latency, multi-channel experiences that scale across our entire customer base.

• Ship Voice & Text Agents: Architect and ship voice and text agent pipelines that handle real-time, multi-turn customer interactions.
• Reasoning vs. Latency: Make principled trade-offs between reasoning depth and latency across frontier LLMs, smaller models, and routing strategies.
• Lead a Pod: Lead a small pod of ML and platform engineers; raise the bar on agent evaluation, observability, and incident response.
• Define Quality: Partner with Product and Voice channel teams to define KPIs, eval harnesses, and acceptance criteria for agent quality.
• Optimize for Voice: Drive selective Small Language Model (SLM) fine-tuning and inference optimization for voice latency and cost.

• You have 5+ years of experience developing and scaling web-based applications, preferably in a SaaS environment.
• You have shipped production AI agents serving real users in voice and/or text channels.
• You think in pipelines and systems, not just models.
• You move fast, deliver impact, and maintain sound engineering judgment.
• You are humble, collaborative, and low-ego, and you elevate those around you.
• You value work-life balance as a foundation for sustained high performance.

• Agent frameworks: Deep, shipped experience with Lang Chain, Lang Graph, Lang Smith, and Lang Chain Deep Agents (or equivalent agent frameworks).
• Voice stack: Hands-on with Voice-to-Voice models and traditional TTS / STT pipelines; understands the trade-offs between end-to-end voice models and modular STT > LLM > TTS architectures.
• LLM fluency: Strong grasp of LLM reasoning behavior, tool use, structured output, and reasoning-vs-latency trade-offs across providers.
• Telephony & cloud: Production experience with Twilio (or comparable telephony) and AWS.
• Engineering: Expert Python, async…