• Design, build, and maintain scalable backend services using Python and FastAPI. • Develop and optimize high-performance RESTful APIs powering AI agents and GTM workflows. • Architect and maintain cloud-native infrastructure (compute, storage, networking). • Build reliable data pipelines and services that process, validate, and serve large B2B datasets. • Ensure system scalability, observability, and fault tolerance. • Own backend features end-to-end — from design and implementation to deployment and monitoring. • Collaborate closely with frontend and data engineers to ensure clean API contracts and reliable data flow. • Contribute to architectural decisions, code reviews, and engineering best practices. • Continuously improve performance, security, and maintainability across backend systems.

This description is a summary of our understanding of the job description. Click on 'Apply' button to find out more. Role Description We are searching for a Senior Fullstack Engineer to join a fast-growing Series A health technology startup focused on an innovative at-home monthly blood testing and health insights platform. The main product is an easy, painless at-home kit for collecting your own blood sample. Your results appear in a private, HIPAA-compliant dashboard where you can track your biomarker changes over time and understand their implications for your health. The Tech Stack: - TypeScript end-to-end - Express - React - Router 7 (web) - tRPC - React Native (mobile) - React Query - Postgres + Redis What You’ll Do: - Own features end-to-end — from design discussion to production rollout and monitoring. - Ship TypeScript on the web app, Node/Express backend, and/or mobile app. - Design and build fault-tolerant, HIPAA-compliant services with a strong focus on privacy, security, and stability. - Document your work so others can move fast. - Use the latest AI tools and SDKs to build AI-enriched features. Qualifications - 6+ years of hands-on software experience, with advanced TypeScript skills. - Comfortable working in a fast-paced startup where procedures aren't clearly defined. - Ability to manage your own time, break down ambiguous problems, and deliver. - Experience using AI tools as an accelerator—never as the decision-maker. - Understanding of backend design and data modeling in SQL/Postgres. - Experience writing reliable tests with Vitest, Cypress, Jest, etc. Requirements - Experience with AI SDKs (AI SDK, OpenAI, Anthropic, etc.) with production software. - Experience building or maintaining HIPAA-compliant or other regulated healthcare software. - Comfortable with internal tooling (e.g., Retool) and thorough documentation habits. - Deeper expertise in React Native or sophisticated systems architecture. - Comfortable with monorepos. Benefits - Salary: $160k – $210k - Equity: 0.05% – 0.25% - Benefits: Health, Dental, Vision - Time Off: Flexible PTO - Work Setup: Fully remote

• working responsibly with stakeholders using team tools (Slack, Jira, Github) • driving decision-making processes that match importance and urgency • fostering productive discussions and encouraging critical thinking • collaborating with Product, Design, and Data teams to plan solutions • building technical solutions using Node.js, TypeScript, PostgreSQL, Terraform, and AI • deploying and managing services in AWS environments • improving reliability through testing, observability, monitoring, and deployment automation • participating in support rotations and incident management • evaluating and improving team processes through reflection and experimentation

• Build and maintain scalable backend services and APIs that power the AI Configs product • Collaborate with internal stakeholders, including product managers, designers, and other LaunchDarkly engineering teams • Continuously optimize the performance, reliability, and scalability of backend systems • Participate in architecture and design discussions • Keep up-to-date with the latest developments in the AI field and in software development best practices • Take ownership of code in production, participate in on-call rotations