Frontend Developer

Company DescriptionInstanvi is a digital and financial external team that specializes business software for medium and large enterprises. We provide software for Bookkeeping, Market Intelligence and TaxationRole DescriptionAre you a Frontend Engineer who truly understands the "why" behind every line of code? We are looking for a Senior Frontend Engineer to join our team and help us build the next generation of our high-performance platform.We aren't just looking for a React developer—we need an engineer who is a master of fundamentals and has significant, production-ready experience with the Next.js framework.What We Need You to MasterThis role requires a deep, uncompromising understanding of the entire frontend stack:JavaScript/TypeScript Fundamentals: Not just surface-level knowledge, but a deep command of ES6+, asynchronous programming (Promises, async/await), and modular design.React.js Proficiency: Expert-level skill with modern React, including Hooks, Context API, performance optimization, and custom component architecture.Next.js Mastery: Proven experience leveraging Next.js for high-stakes, production applications. This includes:Server-Side Rendering (SSR) / Static Site Generation (SSG)The latest App Router and component rendering patterns.API Routes and seamless data fetching strategies.Web Performance & Optimization: A passion for Core Web Vitals, code-splitting, bundle analysis, and delivering lightning-fast user experiences.