Senior AI Software Engineer

At Sword, we’re building AI to heal billions and unlock humanity’s full potential. In doing so, we’re pioneering AI Care, a fundamentally new approach to healthcare built for medical reasoning, safety, and real-time treatment, not generic technology applied after the fact. As both a clinical-centric frontier AI lab and an applied AI platform, Sword is reimagining how care is delivered at scale, removing traditional barriers like appointments, waiting rooms, and stigma so more people can access the care they need—and ultimately get back to lives lived in full. Since 2020, Sword has expanded across physical therapy, women’s health, cardiometabolic, and mental health, and is now moving beyond the session to a fully AI-native, 24/7 care program that brings physical activity, therapeutic exercise, psychotherapy, nutrition, and behavior change into one connected experience. More than 700,000 members across three continents have completed over 10 million AI sessions, helping 1,000+ enterprise clients avoid more than $1 billion in unnecessary healthcare costs. Backed by 42 clinical studies, 44+ patents, and more than $500 million raised from leading investors including Khosla Ventures, General Catalyst, and Founders Fund, Sword is defining a new standard for healthcare. AI Proficiency at Sword AI fluency is a core expectation at Sword. Every candidate is assessed against our three-level framework — be ready to share real examples of how AI is already part of how you work. Explorer (Level 1) — Uses AI daily to boost personal productivity Builder (Level 2) — Creates workflows and tools that elevate the whole team Integrator (Level 3) — Embeds AI into products and processes at scale Every hire must demonstrate at least Level 1. The expected level will vary depending on the seniority of the role. What you’ll be doing: Design, deliver and continuously improve our AI agents, including real-time voice agents, and the LLM-powered products around them; Build and scale the production backend and platform behind the agents, with high volume, high throughput and reliability in mind; Integrate agents into our software flows, and bring new models into the platform with the benchmarks and evals to assess them; Own architecture and design decisions across agents, voice pipeline and platform; Grow the AI function by defining practices, raising the bar in review and mentoring colleagues. What you need to have: 4+ years building and running production software; Deep expertise in at least one of the following: software architecture and design of high-throughput, scalable systems; building agents and integrating them into production software; real-time voice agents (telephony, STT, TTS, latency budgets); Working understanding of how LLMs are built and how they behave; Solid experience with Python, SQL and event-driven design; Experience with cloud platforms (ideally GCP); Experience leading complex, ambiguous projects from…