Senior Front-End Developer

• Develop, maintain, and optimize modern web applications using JavaScript (ES6+), HTML, and CSS.

• Build scalable, reusable, and maintainable UI components and front-end architectures.

• Design responsive, accessible, and high-performance user interfaces.

• Write clean, modular, and well-documented code following best practices and coding standards.

• Conduct thorough code reviews and provide constructive feedback to ensure high code quality and performance.

• Collaborate closely with designers, backend engineers, and product stakeholders to translate business requirements into robust UI solutions.

• Contribute to the full software development lifecycle (SDLC), from requirements and design through deployment and monitoring.

• Implement unit, integration, and end-to-end tests.

• Identify and resolve performance bottlenecks (e.g., rendering, bundle size, network issues).

• Optimize applications for speed and scalability (e.g., lazy loading, code splitting).

• Stay up to date with evolving front-end technologies, frameworks, and browser APIs.

• Advocate for best practices in UX, performance, and maintainability.

• Strong JavaScript expertise, including a deep understanding of:

• JavaScript fundamentals
• ES6+ features (closures, promises, async/await, modules)
• Prototypal inheritance
• Functional programming concepts

• Deep understanding of browser internals, including:

• Event loop, call stack, task queue, microtasks
• Rendering pipeline (reflow, repaint, compositing)

• Strong knowledge of HTML5 and semantic markup
• Advanced understanding of CSS, including:

• Cascading and specificity
• Layout systems (Flexbox, Grid)
• Responsive design
• Animations and transitions

• Production experience with React 17+/18, including hooks, context, composition patterns, error boundaries, and performance optimization (memoization, lazy loading, code splitting)
• Understanding of both server state (e.g., React Query, SWR) and client state (e.g., Valtio, Zustand, Redux)
• Experience integrating REST APIs
• Strong understanding of web performance optimization techniques
• Experience with CI/CD pipelines, including Docker builds, branch-based deployment strategies, and environment variable management across environments (dev/staging/prod)
• Experience with testing frameworks (e.g., Jest, Vitest, Cypress, Playwright)
• Proficiency with CSS-in-JS solutions (e.g., Emotion, Styled Components), including theming, dynamic styles, and SSR style injection
• Strong problem-solving skills and attention to detail
• Fluency in English (written and spoken), along with excellent communication skills and the ability to collaborate effectively in international teams

Nice to Have

• Experience with TypeScript and strong typing patterns
• Familiarity with SSR/SSG frameworks (e.g., Next.js, Nuxt)
• Experience with design systems and component libraries
• Knowledge of Progressive Web Apps (PWAs)
• Familiarity with Azure (especially Front Door and storage for static assets)
• Basic understanding of backend concepts (APIs, authentication flows, microservices)
• Experience with monitoring tools (e.g., Dynatrace)

At wikifolio.com an exciting job environment awaits you in a dynamic, constantly growing and multiple award-winning fintech. Experimenting, failing early, learning and continuing is our motto. An innovative working world with opportunities for professional development is our goal. Expect real work-life balance as well. Become part of our team - we live by our values transparency, fairness, ambition, sustainability and joy and make investing available for everyone.

wikifolio.com is the most well-known fintech organisation in the B2C investment sector in the German-speaking world, growing consistently since 2012.

We believe that everybody should be able to invest successfully in the capital markets – regardless of whether you have €100 or €100,000 to invest. We stand for the democratisation of the investment market - and put our users at the centre of our focus.