For our client we are looking for Senior Fullstack Developer / Tech LeadAbout the productA cloud‑based solution with a Chrome extension at its core to capture and process high‑value data from e‑commerce stores. Your mission is to design and lead the technical direction of the extension and the data pipeline, and to deliver hard, dashboard‑heavy frontends that turn raw signals into actionable insights.What you’ll doOwn architecture and end‑to‑end delivery of a production‑grade Chrome extension (Manifest V3), including content scripts, background service workers, permissions model, secure storage, and messaging.Design data‑collection strategies on storefronts (catalog, pricing, availability, promotions) and instrument data flows from the browser to our cloud.Build dashboard‑centric UIs (performance‑focused, pixel‑perfect, accessible) that present complex datasets clearly and responsively.Integrate Rust → WebAssembly (WASM) components for performance‑critical parsing and transformations; define FFI boundaries and TypeScript bindings.Develop and operate Node.js services (APIs, collectors, webhooks) for ingestion, normalization, and enrichment.Ensure legal & policy compliance (GDPR, ePrivacy, Chrome Web Store policies, site terms of use): consent flows, data minimization, retention, DPIA, privacy notices.Establish quality gates (testing strategy for MV3 extensions, E2E, performance budgets, security reviews, CSP).Lead code reviews, mentor engineers, and set engineering standards (SDLC, CI/CD, observability).Collaborate cross‑functionally with Product, Legal/Compliance, and Data to prioritize use cases and ship safely at speed.Tech stack (core)Rust, TypeScript, CSSWebAssembly (WASM)Node.js (NestJS/Express or similar)Chrome Extension APIs (MV3), CSP, DevToolsHTTP/REST; JSON/NDJSON; storage & messaging in the extensionMust‑have qualificationsSenior‑level experience (6+ years) building production systems and leading architecture decisions.Proven track record shipping one or more Chrome extensions (please include links to the Web Store or repo; MV3 experience strongly preferred).Strong hands‑on skills in Rust (systems/performance) and compiling to WASM; practical experience with wasm-bindgen / wasm-pack or equivalent.Advanced TypeScript and CSS for complex, data‑dense dashboards (performance, accessibility, responsive design).Solid Node.js experience (designing APIs, integration, and operational resilience).Demonstrable knowledge of legal and policy aspects of web data collection (GDPR/ePrivacy compliance, consent models, privacy notices, data retention, DSAR handling, Chrome Web Store policies, robots/terms considerations).Comfortable defining non‑functional requirements (security, performance, telemetry) and enforcing them in CI/CD.OfferHigh ownership of architecture and the technical roadmap.100% remote, flexible hours, and B2B collaboration.Hourly rate up to 200 pln / hA pragmatic, senior team and a delivery‑first culture.