Senior Software Engineer (Backend)

ABOUT COUNSEL http://counsel.health/ Counsel’s mission is to multiply the world's healthcare capacity. We believe in a future in which every person has a personalized, AI-enabled doctor always in their pocket. To accomplish this, we’re building the first fully-vertical, AI-native medical group from the ground up. We’ve redesigned the entire clinical stack with custom AI tools that make our in-house physicians 10x faster and smarter. [learn more on our blog https://www.counselhealth.com/blog] Since our founding in 2023, we have formed partnerships with leading healthcare organizations and are on track to serve hundreds of thousands of patients on our platform within the next year. We have raised over $35M from a16z, Google Ventures, Pear VC and other top-tier VC firms. Our team combines deep expertise in medicine (Harvard, Mt. Sinai, Mass General, UCSF) and technology (MIT, Google, DeepMind, NVIDIA, Stripe, Meta) — and we’re looking for exceptional people to join us as we scale. Join us as we build the future of AI in healthcare! ----------------------------------------------------- ABOUT THE ROLE We are seeking a talented, driven, and experienced Senior Backend Engineer to join us in defining the future of AI + human healthcare. You will sit on our Platform & Integrations team and own the critical product primitives that the rest of the company builds on — including external APIs, health data models, retrieval infrastructure, and enterprise integrations. This role is central to ensuring our platform scales seamlessly — supporting enterprise healthcare clients, powering AI-driven clinical workflows, and maintaining correctness and reliability across distributed systems. Much of this surface area is greenfield, particularly in how we model and operationalize longitudinal health data from wearable devices and external systems. Our culture is fast-paced and ambitious, and we aim for every team member to be exceptional. WHAT YOU’LL DO - Design and evolve our external API and embedded product layer, ensuring long-term stability, disciplined versioning, and enterprise-grade API craftsmanship. - Evolve our agentic retrieval harness to support both patient and clinical search workflows across structured and unstructured data, with strict permission and audit guarantees - Build reusable platform primitives that allow external partners to embed and extend our AI capabilities — ensuring every integration produces lasting platform leverage. - Contribute to our core data models that unify structured health records, unstructured inputs, and high-frequency time-series signals. EXAMPLES OF PROJECTS YOU MAY WORK ON - Develop a pluggable ingestion framework that normalizes data from third-party sources into canonical internal models, with extensible adapters for new partner onboarding. - Build a stateful, multi-turn, agentic API that allows external clients to customize AI agent behavior and capabilities within their own cloud, deployment environments. WHAT YOU'LL BRING - 5+ years building production backend systems, ideally in high-growth environments. - Experience designing and maintaining external-facing APIs used by customers or partners. - Strong data modeling instincts, particularly around time-series or high-frequency data. - Experience working with distributed systems and multi-tenant architectures. - Comfort contributing to greenfield architectural design while shipping pragmatically. WHO YOU ARE - You care deeply about API craftsmanship and long-term system design. - You’ve built complex systems that external customers rely on. - You enjoy modeling messy real-world data — especially high-frequency signals — into clean, durable abstractions. - You’ve built comprehensive search or RAG production systems at scale. - You’ve helped scale early systems from 1 → 10 in a fast-paced environment. - You thrive in small, high-leverage teams where ownership is real. - You have a track record of maintaining and up-leveling operational excellence acr