Senior Software Engineer, Full-Stack & AI Systems

Sully.ai is on a mission to create superhuman doctors by eliminating distractions and guiding them to the best treatments, believing access to doctors is a basic human right. The company, backed by YC and $25M, seeks a Senior Software Engineer for its Engineering Research team. This role involves architecting and scaling platform-level agentic AI systems, combining full-stack engineering with LLM expertise to build reliable, fast, and cohesive multi-agent ecosystems.

Must Have

• Architect and implement cross-agent systems that power core Sully.ai experiences.
• Build and scale full-stack product components using TypeScript/React and Python services.
• Integrate LLMs into production workflows with strong contracts, observability, and test coverage.
• Develop shared UI components and typed SDKs to unify cross-agent experiences.
• Lead engineering direction, collaborating with founders and cross-functional stakeholders.
• Senior-level full-stack experience in React, TypeScript, and Python.
• Proven ability to design, ship, and scale LLM-powered applications.
• Expertise in API design, streaming, and CI/CD pipelines.
• Strong cloud infrastructure background (AWS, GCP, or Azure).
• Track record of building reliable systems with measurable performance and error budgets.

Good to Have

• Experience with WebRTC or audio-aware UI design.
• Hands-on work with agentic AI frameworks.
• History of creating design tokens, SDKs, or cross-agent platforms.

Perks & Benefits

• Shape the Future of Healthcare.
• Early-Stage Impact.
• Remote-First Culture.
• Competitive Compensation (salary, equity).
• Solve Scalability Challenges.

About Sully.ai

Our mission is "One Human, One Doctor". We are creating superhuman doctors, because access to doctors is a basic human right.

Start with making doctors superhuman. Our vision is to eliminate doctor distractions and help them navigate the best treatments for their patients.

About the role

About Us

👏 Team from OpenAI, DeepMind, NASA, GoogleX, Tesla, and 2 physicians: 6 exits, 2 IPOs.

🔥 Our model outperforms Claude, Gemini, and GPT-4.5 on clinical benchmarks.

📈 400+ healthcare orgs signed in 16 months.

⚡️ $25M raised from YC, Amity Ventures, Sequoia scouts, and more.

🌎 $1T+ market opportunity. We’re going after all of it.

About the Role

We are seeking a Senior Software Engineer to architect and scale Sully.ai’s platform-level agentic AI systems within our Engineering Research team. This role combines full-stack engineering excellence with deep expertise in LLM-powered experiences. You’ll design, implement, and optimize core components across frontend, backend, and model integrations, while driving engineering direction in close collaboration with our co-founders. Your work will directly shape the reliability, speed, and cohesion of Sully.ai’s multi-agent ecosystem.

Key Responsibilities

• Architect and implement cross-agent systems that power core Sully.ai experiences.
• Build and scale full-stack product components using TypeScript/React and Python services.
• Integrate LLMs into production workflows with strong contracts, observability, and test coverage.
• Develop shared UI components and typed SDKs to unify cross-agent experiences.
• Lead engineering direction, collaborating with founders and cross-functional stakeholders.

Hard Requirements

• Senior-level full-stack experience in React, TypeScript, and Python.
• Proven ability to design, ship, and scale LLM-powered applications.
• Expertise in API design, streaming, and CI/CD pipelines.
• Strong cloud infrastructure background (AWS, GCP, or Azure).
• Track record of building reliable systems with measurable performance and error budgets.

Nice-to-Have

• Experience with WebRTC or audio-aware UI design.
• Hands-on work with agentic AI frameworks.
• History of creating design tokens, SDKs, or cross-agent platforms.

First-Month Focus

• Audit current cross-agent flows for UI/UX cohesion.
• Implement shared components and typed contracts for reliability.
• Establish instrumentation for frontend performance and model round-trip tracing.

Success OKRs (90 Days)

• Deliver end-to-end tested, production-grade agentic workflows with <5% error rates.
• Launch cross-agent design system and SDK used by at least 2 internal teams.
• Establish weekly “deploy and measure” cadence with performance metrics and error budgets.

Culture Fit

• Persistent, driven problem solver
• Willing to push back on leadership to defend quality/timelines
• Thrives in high-ambiguity, fast-paced startup environments

Why Join Sully.ai?

🔥 Shape the Future of Healthcare: Build category-defining partnerships that enable doctors to focus on saving lives.

📈 Early-Stage Impact: Join early and play a critical role in shaping our partnership roadmap and overall company growth.

🌎 Remote-First Culture: Work with a talented, mission-driven team in a flexible, remote environment.

💰 Competitive Compensation: Enjoy a competitive salary, equity, and the opportunity to make a real difference.

🏆 Solve Scalability Challenges: Tackle complex challenges in a rapidly growing company, driving impactful change in healthcare.

Sully.ai is an equal opportunity employer. In addition to EEO being the law, it is a policy that is fully consistent with our principles. All qualified applicants will receive consideration for employment without regard to status as a protected veteran or a qualified individual with a disability, or other protected status such as race, religion, color, national origin, sex, sexual orientation, gender identity, genetic information, pregnancy or age. Sully.ai prohibits any form of workplace harassment.