Full Stack AI Engineer

About Carda Rehab is a pain. So much so that only 10% of qualifying Cardiac and Pulmonary patients attend. At Keystone AI , we’ve reimagined rehab. Our program allows patients to complete inspiring, convenient, life-saving therapy remotely. Who are we? We are a team of clinicians, data scientists, mathematicians and repeat entrepreneurs. And a few recovering financiers. Our belief is that technology and data, when applied to the right problem, transforms people’s lives and changes even the most entrenched industries. Carda was founded by Harry and Andrew, two friends from Wharton who share a family history of heart disease and experience with poor access to care. We now work with some of America’s largest and top-ranked hospitals and most innovative insurers. We are fortunate to be backed by some of the best investors in the business who have also backed the likes of Livongo, Hinge, Calm, MDLive, and others. What we're looking for We are looking for a talented AI Engineer who loves building impactful AI-powered products that meaningfully improve patient lives. You’ll work across the AI product stack from research and model evaluation to backend integration and product UX. You’ll have the opportunity to work directly with the CTO and CPO to design, deploy, and scale AI-driven features that power the future of Keystone AI . As our first AI hire, you will set the standard for how we apply AI to core business and product workflows. You will have strong technical ownership and help navigate uncharted business, product, and AI/ML challenges. This is a full-time position. In this role, you'll: Collaborate with clinicians, product managers, and other engineers to identify high-impact AI use cases and bring them to life Rapidly prototype ideas using off-the-shelf tools like OpenAI, Hugging Face, LangChain, Pinecone, and anything else that helps us move fast Develop, optimize, and maintain AI agent workflows, ensuring high-quality interactions, scalability, and adherence to user safety standards Integrate AI workflows with backend API services and infrastructure, ensuring seamless deployment, robust performance, and clear observability Design and manage prompt engineering, evaluation, and optimization workflows Build out our internal AI stack and shape best practices — technically and ethically — as we scale What you bring to the team: History of technical ownership for significant engineering projects Deep understanding of how LLMs and foundation models work under the hood 2+ years of hands-on experience in AI-focused engineering roles, with a strong grasp of fundamentals including prompt engineering, retrieval-augmented generation (RAG), agents, and model evaluation 5+ years of full-stack or backend-focused software engineering experience Fluency with APIs like OpenAI, Gemini, Claude along with open-source foundation models Familiarity with the intersection of audio processing and conversational AI Experience building and shipping software end-to-end in fast-paced environments Strong proficiency in Python Comfort with ambiguity and short feedback loops A passion for building products that make a real-world impact Bonus if you have: Experience with voice AI agents using WebRTC/Websockets with tools like LiveKit, Pipecat, or Daily Proficiency in data mining, statistical analysis, and predictive modeling algorithms Familiarity with cloud services like AWS or Google Cloud, particularly for deploying and scaling AI-powered applications Experience working with HIPAA compliant applications and healthcare data (FHIR, HL7, clinical notes, etc.) Originally posted on Himalayas