We are looking for a Senior Web Engineer to work on a high-performance, security-critical Web SDK.This is a low-level frontend role, focused on performance, browser APIs, and secure integrations.Key Responsibilities- Develop and maintain a TypeScript-based Web SDK - Build framework-agnostic components using Web Components - Integrate with backend via WebSockets / real-time communication - Ensure performance, security, and resistance to reverse engineering - Contribute to testing (integration / E2E)Core Requirements- Strong TypeScript / JavaScript - Experience with Web Components (Custom Elements, Shadow DOM) - Solid understanding of browser performance & rendering - Experience with WebSockets and 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) - Docker and basic KubernetesProfile- Strong engineering fundamentals (beyond frameworks) - Comfortable with low-level web concepts - Able to balance performance, security, and usabilityThis is a fully remote role, but candidates must be currently based in Portugal.