Senior Full-Stack Engineer

MEET ASCERTAIN Ascertain is building AI agents to automate the administrative work that burdens care teams. We are in major health systems and large specialty groups, saving hundreds of staff hours every week. Our backers include Northwell Health, New York’s largest health system, and Deerfield Management, a leading healthcare investment firm. Together, we’re on a mission to restore time, trust, and focus to the people who keep healthcare running. Our work is urgent — not because of startup timelines, but because our customers rely on us to drive financial resilience and operational clarity in a system under strain. ABOUT THE ROLE As a Senior Full-Stack Software Engineer at Ascertain, you'll ship product across the stack—from backend services and data infrastructure that power Ascertain’s healthcare AI platform to the web app that our partner operations team members use every day. You'll join a growing team of engineers, with real ownership over what we build, how we build it, and the engineering culture we grow into. We're headquartered in New York City with a hybrid team there, plus remote engineers across the U.S. and Brazil. We operate with high autonomy, shared accountability, and deep respect for the people who use our software. WHAT YOU'LL DO - Own product features end-to-end, from design through production. - Build user-facing experiences in React and TypeScript. - Design and ship backend services with Python and FastAPI. - Partner with product, design, and engineering peers to turn fuzzy problems into shipped software. - Raise the bar in code review and help shape our engineering practices. - Improve our development processes as we grow—testing, CI/CD, observability—the things that compound over time. WHAT WE'RE LOOKING FOR - 5+ years strong full-stack experience with Python (FastAPI or similar) and TypeScript with React. - Comfort designing schemas and writing non-trivial SQL against relational databases (we use PostgreSQL). - Working knowledge of containerization (Docker) and CI/CD pipelines. - Familiarity with Redis, queueing systems, or other parts of a modern production stack. - Experience building and operating production systems in a cloud environment (we use GCP). - Ability to communicate clearly in English, written and verbal—most async work happens in writing, and you'll regularly join meetings with U.S.-based teammates. - Background in ambiguous, early-stage environments where you've had to take ownership without much scaffolding. - Meaningful overlap with U.S. Eastern business hours during the workday. NICE TO HAVE - Experience in regulated environments (healthcare, fintech, etc.) and a security-minded approach to design. - Infrastructure-as-code experience (Terraform). WHO YOU ARE You're excited—not just willing—to learn new things, push past your comfort zone, and ship in a fast-moving environment. You communicate clearly, take ownership without being asked, and care about the people on the other end of your code. BENEFITS & PERKS - Cutting-edge technology: Work directly with the latest advancements in generative AI and automation, tackling challenging problems that meaningfully impact healthcare. - Ownership & growth: You’ll join Ascertain at a pivotal early stage, shaping our products, technical direction, and culture, with significant opportunities for career advancement. - Collaborative team: Join a talented, passionate, and supportive team with backgrounds from top tech companies and clinical institutions. - Competitive compensation: We offer competitive salary, meaningful equity, comprehensive health insurance, and more. Why Ascertain? Make a real difference: Your work will directly impact healthcare organizations and improve patient care. Join Ascertain in transforming healthcare with AI!