Senior Software Engineer, Full-Stack and AI Systems

Madfish; Remote; GBP 70,000 - 100,000; Full time

Job summary

A pioneering healthcare tech startup is looking for a Senior Software Engineer to architect and scale platform-level AI systems. This role combines full-stack engineering expertise with a focus on LLM-powered experiences. You will lead engineering initiatives, collaborate closely with co-founders, and be instrumental in shaping the company's multi-agent ecosystem. Competitive compensation and a remote-first culture are offered, making this an exciting opportunity to impact healthcare technology significantly.

Benefits

Competitive salary

Equity

Flexible remote work environment

Qualifications

• Senior-level full-stack experience required in React, TypeScript, and Python.
• Proven ability to design, ship, and scale LLM-powered applications.
• Strong cloud infrastructure background necessary.

Responsibilities

• Architect and implement cross-agent systems.
• Build and scale full-stack product components.
• Integrate LLMs into production workflows.

Skills

Full-stack experience in React

Full-stack experience in TypeScript

Full-stack experience in Python

API design

Cloud infrastructure (AWS, GCP, Azure)

Job description

Role Overview

We are seeking a Senior Software Engineer to architect and scale our platform-level agentic AI systems. 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 company’s multi-agent ecosystem.

Key Responsibilities

• Architect and implement cross-agent systems that power core platform 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.

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

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.

Why Join Us?

🔥 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.