Senior AI Models Engineer

We’re Heidi. We're building the future of healthcare by giving every clinician the earth's finest AI Care Partner. In just 18 months, our clinical AI products have absorbed the administrative chaos of 73 million patient visits. Today, we support over 2.5 million patient sessions a week across 190+ countries. Healthcare systems are failing us; clinicians spend more time on documentation than on patients, and the human connection that makes medicine worth practicing is eroding. Our mission is simple: double the world’s healthcare capacity and strengthen the human connection at its heart. We found product-market fit with a freemium medical scribe that clinicians love. Now, we're expanding. Every task a clinician hands to Heidi is a patient who feels more attended to, a health system unclogged, and a clinician who gets to be a clinician again. If you don’t choose easy and you want to build something way bigger than yourself then, choose the challenge, choose Heidi. The Role We help enterprise customers build AI systems tailored to their specific work. Our goal is to deliver better economics than relying solely on closed-source models such as Claude, Gemini, and OpenAI. You will work across model customisation, deployment, agent systems, and customer delivery. We do not expect one person to specialise in everything. You should bring strong experience in at least two of these areas and be comfortable collaborating across the others. What you will do As a Senior, you will own system design, technical decisions and customer outcomes. Your responsibilities will include: Model customisation Turn customer use cases into training and evaluation plans. Select suitable data, models, and training approaches. Fine-tune and evaluate models for specialised domains. Improve quality based on testing and production feedback. Deployment and inference Design cost-effective cloud or on-prem deployment approaches. Select suitable infrastructure and serving configurations. Improve reliability, latency, and operating cost. Build monitoring, backup, and recovery processes. Agent systems Build agent workflows around language models. Connect models with customer data, tools, and existing systems. Add the controls and observability needed for production use. Customer delivery Work with customers to understand their requirements and constraints. Explain trade-offs between quality, cost, privacy, and complexity. Help take solutions from early discovery through production launch. What we will look for Strong experience in at least two of the areas above. Practical experience building or operating production AI systems. Solid software engineering or machine learning engineering skills. Familiarity with open-weight language models and the modern LLM ecosystem. Good judgement when balancing model quality, cost, latency, and reliability. The ability to work through ambiguous technical and customer requirements. Clear communication with both technical and non-technical stakeholders. How we show up Build for the next decade, not next quarter . Our targets are outrageous on purpose. The world's health doesn't have the luxury of incrementalism. Lead, don't wait . We treat tomorrow's problems today. Sometimes we build what's needed before it's wanted, and we're fine with that. Follow the evidence . Trust the patient. We pursue truth relentlessly. But when the subjective and objective disagree, we treat the patient, not the numbers. Ego is a comorbidity we can't afford. Own the outcome . Everyone here carries the company. Raise problems with solutions, solve them end-to-end, and never be a bystander. Ship, measure, go again . A button today, a workflow tomorrow. More iterations beat better planning. We're precise at pace, not reckless. Live in clinicians' reality . Not the ideal workflow, the twenty-patients-before-lunch actual one. We build for exhausted humans, and we'd better be decent ones while we do it. Why Heidi? You’ll join a team focused on real-world impact over imaginary valuations and glossy PR. We live and breathe the challenges of modern health systems, and are laser-focused on exacting the change we’d like to see. We’re medicos, engineers, builders, and designers who’ve felt the moral and practical toll of what non-care feels like. True A-players progress extremely fast here. The nature of the scale-up game is demanding, but we value sustainable performance and mental health. You're trusted to perform, and you set your schedule. We operate on outcomes > inputs, not process theatre. We all take the bins out, metaphorically and literally. Building what we’re building isn’t always easy. But we didn’t choose easy, we chose to build something that actually matters. We hold ourselves to a higher standard because healthcare demands it. If you join Heidi, you recognise that the deeper question isn’t whether AI can solve the global healthcare crisis, but whose hands will shape it. The work is hard, but you will trust and admire the people you work beside, and rest easy knowing you’re doing the defining work of your career. We take care of you. We offer a $1,000 annual learning and development budget, a $150/month health and wellness allowance, a $500 home office budget, 26 weeks paid primary parental leave and 18 weeks paid secondary parental leave, fertility support up to $10,000, four weeks of work from anywhere per year, and serious equity. Heidi is dedicated to creating an equitable, inclusive, and supportive work environment that brings people together from diverse backgrounds, experiences, and perspectives. Our strength is in our differences. We're proud to be an equal opportunity employer and welcome all applicants as we're committed to promoting a culture of opportunity for all.