Senior Full Stack Engineer / Web SDK Architect – Deep-Tech E-Commerce (React/Node/Wasm)

About Us Anproba is a deep-tech Retail/Fashion-Tech startup building the next generation of Virtual Try-On (VTO). We are bypassing the latency and cloud-GPU costs of traditional AI image generation by utilizing a proprietary edge-computing architecture. We extract garment data via cloud computer vision (Module A), package it into ultra-lightweight FlatBuffers, and use a native Thin-Plate-Spline (TPS) C++ solver to render the fabric deformation directly on the user's device in sub-milliseconds. The Reality of the Role To move fast and validate our UX, we prototyped our initial web platform, SDKs, and e-commerce integrations using AI-generation tools (Claude/LLMs). It looks great, but as a Senior Engineer, you know the reality: AI writes "happy path" code that does not survive contact with enterprise production environments. We are not looking for someone to blindly "maintain" this AI code. We are looking for a Lead Full Stack Architect who has the seniority to audit these prototypes, salvage the UI components, and ruthlessly rewrite the underlying architecture, state management, and security layers for enterprise scale. Phase 1: The "Stripe-Style" Web SDK Your first major objective is to build a drop-in Web SDK. We want e-commerce merchants to paste a single script tag into their website to instantly enable our VTO interface. The Challenge: You will be injecting a React/TypeScript widget into hostile, unknown environments (legacy jQuery, messy CSS, conflicting global variables). The Requirement: You must architect the SDK using Shadow DOM or iFrames for total style/script isolation, and use advanced bundlers (Rollup/Vite) to keep the initial page load footprint under 100kb. Phase 2 & Future Roadmap Once the core SDK is bulletproof, you will lead the full-stack expansion: WebAssembly (Wasm) Integration: Working with our core C++ engineers to compile our native TPS rendering engine into Wasm/WebGL so it can run directly inside the browser. E-Commerce Plugins: Building robust, rate-limit-compliant, and secure backend integrations for Shopify, WooCommerce, and BigCommerce. Authentication & Security: Implementing strict OAuth2 flows, secure API key rotation, and ensuring our zero-knowledge biometric data pipelines are GDPR compliant (Privacy-by-Design). Required Skills & Tech Stack Frontend: Expert-level React.js, TypeScript, and modern state management (Zustand, Redux Toolkit, etc.). Backend: Node.js, Express/NestJS, REST & GraphQL API design. SDK/Widget Architecture: Deep understanding of Shadow DOM, cross-origin communication (postMessage), and extreme bundle optimization (Webpack/Rollup/Vite). Security: OAuth2, JWT, CORS, Webhook signature verification, and secure data transit. Bonus/Highly Desired: Experience with WebAssembly (Wasm), WebGL, or C++ integration in the browser. Experience publishing official Shopify or WooCommerce apps. Who You Are You are an architect, not just a framework consumer. You understand how the browser renders, how event loops work, and how memory is managed. You are paranoid about security and performance. You communicate clearly, document your architecture, and write code that is modular and highly testable. How to Apply To prove you have read this description and understand the complexities of building an SDK, please start your cover letter by answering this one question: When injecting a JavaScript UI widget into an unknown client's e-commerce website, how exactly do you guarantee that your CSS will not break their site, and their CSS will not break your widget? Applications without a specific technical answer to this question will be automatically declined. Project Details Project Type: Long-term / Contract-to-Hire Experience Level: Expert Hours: 20-40 hrs/week (Flexible) Looking forward to your application