Senior Software Engineer C# - FLEXIBLE WORKING in London

About Circadia Health

Circadia Health is a growth-stage healthcare AI company on a mission to prevent avoidable hospitalizations and transform senior-care operations. Our Circadia Intelligence Platform combines:

• Contactless sensing that monitors respiration and motion with medical-grade accuracy
• Predictive analytics & agentic AI workflows that detect 85% of preventable rehospitalizations ~11 days in advance
• Enterprise integrations that embed insights directly into EHR, care-coordination, billing, and compliance systems

Today, our technology touches 40,000+ post-acute patients daily across skilled-nursing, home-health, and home-care networks. We are backed by leading healthcare and AI investors and headquartered in El Segundo, CA.

As a Senior Software Engineer, you will play a critical role in designing, developing, and maintaining both backend APIs and frontend applications that support sensitive healthcare platforms. You will be proficient in Python for backend development and have experience with modern frontend frameworks such as ReactJS, Vue.js, or Angular. Your expertise in Test-Driven Development (TDD), security best practices, and comprehensive documentation will ensure the reliability, scalability, and security of our mission-critical software. Your work will directly impact patient care and enhance the efficiency of clinical staff by contributing to a platform that serves 30k+ patients daily through our Circadia Contactless Monitor (IoT devices)—a number expected to scale beyond 100k+ in the next 2 to 3 years.

Frontend Development:

• Build, develop, and maintain responsive, interactive user interfaces using modern JavaScript frameworks (React, Vue.js, Angular).
• Optimize frontend performance using techniques like lazy loading, code splitting, and caching.
• Design, develop, and maintain RESTful APIs using Python (FastAPI) to support healthcare applications.
• Collaborate with frontend and mobile developers to integrate APIs effectively.

AWS Expertise:

• Build scalable applications using AWS services (Cognito, Pinpoint, IoT, MSK).
• Expand and manage services under AWS modules while implementing robust authentication protocols.
• Navigate Docker deployments to scale containerized applications efficiently.

Write unit tests and integration tests using PyTest to ensure code quality and reliability. Conduct code reviews and implement best practices for high coding standards.

Data Management:

• Manage patient data efficiently using databases (MySQL, PostgreSQL, MongoDB).
• Optimize database queries for performance and scalability while ensuring data integrity.
• Implement and maintain security measures to protect sensitive healthcare data.
• Built scalable ingestion pipelines for high-frequency time-series data.

Advanced knowledge of Python and related frameworks (FastAPI, NumPy, Pandas, Pydantic) including multithreading and parallel design principles. Expertise in JavaScript and frameworks such as ReactJS, with solid frontend experience. Understanding of AWS, including knowledge of Cognito, Pinpoint, IoT, MSK and other services, with hands-on containerized deployments via Docker. Experience with relational and NoSQL databases (MySQL, PostgreSQL, MongoDB). Experience with TDD and testing frameworks such as PyTest. Proficiency in C++ and TypeScript. Experience with AWS-specific services: Familiarity with HIPAA compliance and healthcare application development. Background in regulated industries (healthcare, life sciences, medical devices).

Detail-Oriented: Ability to maintain high levels of accuracy and attention to detail, particularly when developing APIs that handle sensitive healthcare data.

Organization and Efficiency: Capable of managing multiple projects and timelines simultaneously with a keen eye for detail. You take pride in building systems that “just work” at scale.

Compensation & Equity:

• 100% company-paid medical, dental, and vision
• Generous PTO
• Professional development budget