Senior Fullstack Dev

Job Title: Senior Fullstack Developer Location: Remote Contract: Full-time, 40 hours a week About the Role: We're seeking a Senior Fullstack Developer to join us as a foundational technical hire and a true engineering partner to our CTO. This is a high-trust, high-ownership role: you'll take end-to-end responsibility for building features and, just as importantly, for the long-term health and direction of the codebase itself. The ideal candidate is an experienced software developer, real depth across the stack, and expert-level command of TypeScript and React in particular. If you thrive on owning real problems end-to-end, and care as much about architecture and maintainability as about shipping; this role is for you.  What You'll Do End-to-End Feature Development: Take full responsibility for implementing new features across the stack, from designing new subsystems to building the UI, and delivering them to production independently. Architectural Ownership: Own architectural decisions and long-term technical planning in close partnership with the CTO. You'll propose direction, weigh trade-offs, and drive technical strategy. Frontend Design: Own the structure, performance, and maintainability of our client-side application in TypeScript, Next.js, and Tailwind CSS. You'll set patterns for state management, component design, and rendering strategy that the rest of the team builds on. Backend Engineering: Develop and maintain robust Python services, using SQLAlchemy for database interactions and Celery for asynchronous task processing. You should be able to design and reason about backend systems, not just extend them. Technical Debt & Code Health: Proactively identify what needs refactoring and act on it, reducing technical debt rather than adding to it. You'll set and uphold standards that keep the codebase healthy as it grows, balancing delivery speed against long-term maintainability. Real-Time Systems: Implement and troubleshoot real-time features using Streaming, SSE and WebSockets to keep the user experience snappy and reactive.  Quality & Testing: Own the testing strategy across frontend and backend, building the automated coverage needed to keep the platform stable as it scales. Mentorship: Support and guide other developers on the team, sharing context and raising the overall engineering bar.  What You'll Bring Proven Senior Autonomy: 6+ years of professional fullstack experience, including a track record of independently owning a product's development. You can take high-level goals and deliver finished, production-ready work with zero hand-holding. Frontend Expertise: Expert-level proficiency in TypeScript, React, Next.js, Tailwind CSS. You can architect complex frontend applications from scratch, manage state cleanly, and make deliberate decisions about performance and structure. Strong Backend Foundation: Solid, hands-on experience with Python and FastAPI. You understand how to design efficient APIs, manage database transactions via SQLAlchemy, and build reliable async workflows with Celery. You're comfortable owning backend work, not just consuming it. Architectural Judgment: Demonstrated ability to make and defend architectural decisions, plan for the long term, and evaluate trade-offs between speed, complexity, and maintainability. You know when to invest in structure and when to keep it simple. Technical-Debt Discipline: You instinctively spot what should be refactored and can improve systems without breaking them. You leave every part of the codebase you touch in better shape than you found it. Testing Mindset: A quality-first approach, with practical experience across frontend and backend testing frameworks (e.g., Jest, Cypress, Playwright, pytest). Database Knowledge: Strong command of PostgreSQL, schema design, efficient queries, and transaction management. Familiarity with vector databases and S3-like storage is a plus. Adaptability: You move comfortably between shipping features for customers and stepping back to improve system architecture, choosing the right mode for the moment.   Why Join Blocks? Foundational Impact: Be a senior, foundational member of our technical team, directly shaping both the pace and the architecture of our product. Real Ownership & Autonomy: You'll have genuine latitude over how the system is built and evolved. You'll operate with a long leash, and as trust builds, so does the scope of what's yours to own. Open-Source Philosophy: Work with a modern stack built entirely on open-source technologies. Growth & Leadership Potential: Grow with the company and take on increasing technical leadership as the team expands. Dynamic Environment: Thrive in a fast-paced, collaborative, and innovative startup culture.