Senior Full-Stack JavaScript Engineer (Remote - LATAM or Europe)

Senior Full-Stack JavaScript Engineer (Remote - LATAM or Europe) Company: POS+ (posplus.org) Location: Fully Remote (Targeting LATAM or Europe time zones for team overlap) Type: Full-Time Independent Contractor Tech Stack: Node.js, React, TypeScript, PostgreSQL / MongoDB, AWS About POS+ At POS+ (posplus.org), we build the foundational payment interface software that powers modern retail, B2B, and service-industry transactions. Payments architecture is unique: it requires flawless data consistency, zero-downtime availability, low latency, and bulletproof offline-first capabilities. We don't just build web apps; we build mission-critical infrastructure that businesses rely on to process their livelihoods. Because our platform manages complex real-time event loops, financial calculations, and deep peripheral integrations, the quality of our codebase is our highest priority. The Reality of This Role (Read This Before Applying) We are looking for a true Senior Engineer—someone who architectures scalable systems, actively maps out edge cases, and writes highly maintainable code. A note on AI Slop: We know the current state of remote hiring. If you rely on ChatGPT, Claude, or Copilot to blindly vomit boilerplate logic, write your functions, or solve architectural hurdles you don't actually understand, do not apply. We have zero tolerance for AI slop, unreviewed copy-pasted code, or hidden technical debt. We expect our senior engineers to have deep foundational knowledge, a critical eye for code quality, and the ability to explain the why behind every line of code they push. Our Screening Process We respect your time, so we will not make you do an asynchronous, 48-hour take-home coding assignment (where people just use AI anyway). Instead, our interview process is direct and highly collaborative: Initial Intro & System Design (45 mins): A conversation about your past experience, technical scars, and a live virtual-whiteboard system architecture exercise focused on high-throughput data processing. The Live Code Review & Debugging Session (60 mins): You will share your screen with our team. We will give you a functioning but poorly written, messy JavaScript/TypeScript codebase. Your job will be to audit it live—identifying security vulnerabilities, architectural flaws, concurrency issues, and refactoring it for long-term maintainability. What You Will Do Architect, build, and maintain highly scalable full-stack features using Node.js, React, and TypeScript. Optimize complex database queries and schema designs (SQL/NoSQL) to handle massive transaction volumes. Secure and scale our RESTful and WebSocket APIs to ensure instantaneous synchronization between physical POS softwares - both cloud and server-based - and our cloud infrastructure. Proactively identify and eliminate technical debt, enforcing strict linting, type safety, and comprehensive testing frameworks. Work as a direct independent contractor, collaborating synchronously with our core product and engineering leadership. What We Look For 5+ years of verified professional experience running production-grade full-stack JavaScript/TypeScript applications. Production experience dealing with asynchronous programming challenges, race conditions, memory management, and event-driven architectures in Node.js. Deep knowledge of React state management, rendering optimization, and building accessible, modular UI components. Strong communication skills in English—you must be comfortable thinking out loud, defending your architectural choices, and collaborating live via video calls. Experience with cloud infrastructure (AWS/GCP), CI/CD pipelines, and Dockerized environments is a major plus. What We Offer Top-Market USD Compensation: Competitively calibrated based on your geographic location and senior expertise. Direct Contractor Engagement: Clean, streamlined contracting and monthly invoicing. True Autonomy: No micromanagement. You own your modules, write clean code, and execute. Impact: You will be working directly on core systems that impact thousands of real-world merchant locations daily. How to Apply Please submit your resume/LinkedIn profile along with a link to your GitHub/GitLab.