We are looking for aSenior Web Engineerto work on ahigh-performance, security-critical Web SDK .This is alow-level frontend role, focused on performance, browser APIs, and secure integrations.Key Responsibilities Develop and maintain aTypeScript-based Web SDK Buildframework-agnostic componentsusingWeb Components Integrate with backend viaWebSockets / real-time communication Ensureperformance, security, and resistance to reverse engineering Contribute totesting (integration / E2E)Core Requirements StrongTypeScript / JavaScript Experience withWeb Components(Custom Elements, Shadow DOM) Solid understanding ofbrowser performance & rendering Experience withWebSocketsand real-time systemsImportant Knowledge Areas Security fundamentals(OAuth2, JWT, encryption basics, hashing) Performance topics(Canvas / WebGL, WebAssembly is a plus) Testing tools(Playwright, Jest or similar) Dockerand basicKubernetesProfile Strong engineering fundamentals (beyond frameworks) Comfortable withlow-level web concepts Able to balanceperformance, security, and usabilityThis is a fully remote role, but candidates must be currently based in Portugal.