Senior Frontend Engineer (React & SSR)

Description

Job Summary: We are looking for a Frontend/Full-Stack Developer to design and implement complex interfaces and business layers, focusing on code quality, performance, and observability in digital products. Key Highlights: 1. Minimum 5 years of experience in Frontend/Full-Stack development with React 2. Advanced interface development with React, SSR, and performance optimization 3. Building Backend/BFF layers with Node.js, Python, or Kotlin We are knowmad mood! We are a leading digital transformation company, continuously evolving and at the forefront of technology. We were founded to drive real change through innovation and sustainable development, with a mission to deliver value to our clients and empower our talent. Comprising over 3\.000 creative, digital, and innovative people connected to a shared purpose and capable of building connections with individuals worldwide. A responsible, flexible team with high adaptability to our clients’ and the market’s needs — while consistently delivering value, vision, creativity, expertise, professionalism, and passion for technology in every project. Our core values guiding us toward excellence are collaboration, innovation, commitment, fun, and trust. **What do we value?** At least **5 years of experience as a Frontend / Full-Stack Developer**, contributing to the development of **complex digital products** in modern environments. * Solid experience with **React** and current frontend ecosystems. * Deep knowledge of **Server-Side Rendering (SSR)**, hydration, and caching strategies. * Experience building **backend or BFF layers** using **Node.js, Python, or Kotlin**. * Focus on **code quality**, best practices, and automated testing. * Ability to work in multidisciplinary teams with **high autonomy and ownership**. * Strong technical communication skills and sound judgment for decision-making. **What would your responsibilities be?** * **Advanced Frontend Development:** Design and implement complex interfaces with **React**, ensuring production-grade quality, maintainability, and scalability. * **SSR and Performance:** Apply **Server-Side Rendering** strategies, performance optimization, **Core Web Vitals**, and **technical SEO**. * **Backend & APIs (BFF):** Develop and maintain business logic and data orchestration layers using **Node.js, Python, or Kotlin**. * **Testing and Quality:** Implement **unit and E2E testing** (Jest, Vitest, Playwright, Cypress) and integrate them into **CI/CD pipelines**. * **Observability:** Configure and maintain **monitoring, logging, and error management** solutions (Datadog, Sentry, New Relic). * **Technical Collaboration:** Work closely with other developers, product, and business stakeholders, providing technical insight and facilitating decisions. **Additionally, we highly value experience and/or knowledge in:** * **CI/CD** with automated testing integration and deployments. * **Scalable frontend architectures** and engineering principles (SOLID, design patterns). * **Optimizing Time to Market**, balancing technical quality and pragmatism. * Technical documentation and **code reviews** as standard practice. * Working in agile environments and distributed teams. * Strong level of **technical and conversational English**. And with us, you can enjoy: Permanent Contract **100% REMOTE** Internal training and access to certifications. Check our calendar here: https://www.knowmadmood.com/es/talento/formacion Flexible compensation plan (health insurance, transportation, childcare vouchers, meal vouchers) Become a brand ambassador through our friend referral program Refer your friends and earn a bonus! Events, meetups, tech days, talks… and much more! 26 days of leave (22 vacation days, 2 discretionary days, and December 24th and 31st as default holidays) Working hours: 8\.30–18:00 (flexible) Monday–Thursday; Friday 8:00–15:00; Summer intensive schedule (July & August): 8:00–15:00 Stay updated on our news by following us here \-\> knowmad mood *At ***knowmad mood***, we are committed to equal opportunities and respect for diversity. We apply our Equality Plan and the principle of non-discrimination across all our recruitment processes.*