> Markdown version of [/jobs/ext/2505975-sr-machine-learning-engineer](https://www.wearedevelopers.com/jobs/ext/2505975-sr-machine-learning-engineer). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Sr. Machine Learning Engineer - **Company:** AppFolio, Inc. - **Location:** San Diego, CA, United States - **Experience:** Expert - **Salary:** $167,200.0 - $209,000.0 - **Contract:** Permanent contract - **Skills:** Application Programming Interfaces (APIs), Artificial Intelligence, Amazon Web Services, Computer Programming, Github, Python (Programming Language), Machine Learning, Language Modeling, Open Source Technology, Azure Machine Learning, Data Streaming, Twilio, WebSocket, Large Language Models, Multi-Agent Systems, Deep Learning, Model Validation, Low Latency, Docker - **Published:** August 11, 2026 - **Apply:** https://www.indeed.com/viewjob?jk=a237e06aba32f180 ## About the Role * 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. Must Have * 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. Nice to Have * 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. ## Description 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 AppFolio'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. Your Impact * 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. ## Related Videos - [Building AI Applications with LangChain and Node.js](https://www.wearedevelopers.com/videos/1512-building-ai-applications-with-langchain-and-node-js) - [Docker Compose: Rediscovered](https://www.wearedevelopers.com/videos/1978-docker-compose-rediscovered) - [20 billion requests a week: Upgrading Twilio's API gateway at scale](https://www.wearedevelopers.com/videos/100234-20-billion-requests-a-week-upgrading-twilio-s-api-gateway-at-scale) - [Innovating Developer Tools with AI: Insights from GitHub Next](https://www.wearedevelopers.com/videos/1268-innovating-developer-tools-with-ai-insights-from-github-next) - [On a Secret Mission: Developing AI Agents](https://www.wearedevelopers.com/videos/1510-on-a-secret-mission-developing-ai-agents) - [Docker build without Docker](https://www.wearedevelopers.com/videos/100114-docker-build-without-docker) ## Related Articles - [What Are Large Language Models?](https://www.wearedevelopers.com/magazine/304-what-are-large-language-models) - [From Prototype to Production: Build AI Agents with This Free 4-Course Learning Path](https://www.wearedevelopers.com/magazine/655-from-prototype-to-production-build-ai-agents-with-this-free-4-course-learning-path) - [MLOps – What’s the deal behind it?](https://www.wearedevelopers.com/magazine/125-mlops-what-s-the-deal-behind-it) - [MLOps And AI Driven Development](https://www.wearedevelopers.com/magazine/82-mlops-and-ai-driven-development) - [A 5-Step Open-Source Setup for Agentic Engineering](https://www.wearedevelopers.com/magazine/738-a-5-step-open-source-setup-for-agentic-engineering) - [What is Agentic Programming and Why Should Developers Care?](https://www.wearedevelopers.com/magazine/625-what-is-agentic-programming-and-why-should-developers-care)