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 ResponsibilitiesDevelop and maintain a TypeScript-based Web SDKBuild framework-agnostic components using Web ComponentsIntegrate with backend via WebSockets / real-time communicationEnsure performance, security, and resistance to reverse engineeringContribute to testing (integration / E2E)Core RequirementsStrong TypeScript / JavaScriptExperience with Web Components (Custom Elements, Shadow DOM)Solid understanding of browser performance & renderingExperience with WebSockets and real-time systemsImportant Knowledge AreasSecurity fundamentals (OAuth2, JWT, encryption basics, hashing)Performance topics (Canvas / WebGL, WebAssembly is a plus)Testing tools (Playwright, Jest or similar)Docker and basic KubernetesProfileStrong engineering fundamentals (beyond frameworks)Comfortable with low-level web conceptsAble to balance performance, security, and usabilityThis is a fully remote role, but candidates must be currently based in Portugal.