Senior Backend Engineer, Consumer Growth

At Sword, we’re building AI to heal billions and unlock humanity’s full potential. 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. As a Senior Backend Engineer in Consumer Growth at Sword, you’ll build the services that help people discover our products, become paying members, experience value, and stay engaged over time. Working closely with Product, Design, Data, Marketing, and mobile engineers, you’ll turn growth opportunities into reliable, measurable product experiences. Your work will span acquisition integrations, onboarding, subscriptions, and retention, combining rapid experimentation with the engineering foundations needed to scale successful ideas. What you’ll be doing: Design, build, and operate backend services and APIs supporting the consumer journey across web, Android, and iOS; Build subscription and payment capabilities, including checkout integrations, purchase-to-account linking, entitlements, renewals, and subscription lifecycle events; Enable targeted experiences and controlled experiments through feature flags, cohort targeting, and reliable experiment assignment; Implement trustworthy event instrumentation and integrations that help teams understand acquisition sources, funnel performance, and customer behavior; Partner with Product and Data to clarify hypotheses, define measurement requirements, and assess results after launch; Improve performance and reliability across critical journeys, with particular attention to payment correctness, data consistency, and failure recovery; Own changes through design, implementation, testing, deployment, monitoring, and iteration; Use AI tools to accelerate development and troubleshooting while taking responsibility for correctness, security, and maintainability. What you need to have: Experience building and operating backend services in production, with strong experience in TypeScript; Strong foundations in API design, relational databases, data modeling, and automated testing; Understanding of asynchronous processing and distributed systems, including retries, idempotency, and consistency; Ability to translate product goals into pragmatic technical solutions and make clear trade-offs between speed and long-term maintainability; F