[Remote] Sr. Machine Learning Engineer

Note: The job is a remote job and is open to candidates in USA. AppFolio is building an AI-native platform that transforms how the real estate industry operates. The Senior Machine Learning Engineer will design and ship production voice and conversational AI agents within Realm-X, collaborating across Product, Voice, and ML Platform teams to deliver reliable, low-latency, multi-channel experiences. The role also includes leading a small engineering pod, defining agent quality standards, and optimizing models and infrastructure for voice latency and cost.

Responsibilities

• 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

Skills

• * 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 LangChain, LangGraph, LangSmith, and LangChain 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 programming, and WebSockets for real-time, bidirectional streaming
• * ML fundamentals: Solid foundation in deep learning, model evaluation, and inference optimization; able to deploy with Docker on AWS
• * Leadership: Demonstrated ability to lead a small team, mentor engineers, and partner credibly with Product and Design
• * Experience fine-tuning Small Language Models for domain-specific voice applications
• * Familiarity with RAG over structured business data and tool-using agents over API surfaces
• * Prior experience in regulated or customer-facing industries with strict reliability requirements
• * Publicly verifiable work on GitHub, in open-source agent frameworks, or in community competitions

Benefits

• Additional benefits
• Any discretionary bonuses you may be eligible for based on your role and/or employment type
• Regular full-time employees are eligible for benefits
• Coaching and mentorship with best-in-class leaders
• Time and tools to develop your skills
• Hybrid work with a flexible, personal and connected environment

Company Overview

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