Senior Full Stack Engineer – React & Node.js

Description

Job Summary: We are seeking a Senior Full Stack Developer to join an innovative team building scalable and high-performance digital products. Key Highlights: 1. Development of scalable and high-performance digital products. 2. Collaboration on architectural decisions and continuous improvement of the tech stack. 3. Focus on architecture, code quality, and microservices. 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 individuals connected by purpose and capable of building connections with people worldwide. A responsible, flexible team with strong adaptability to our clients’ and the market’s needs — consistently delivering value, vision, creativity, expertise, professionalism, and passion for technology in every project. Our core values — collaboration, innovation, commitment, fun, and trust — guide us toward excellence. **What do we value?** We seek a **Senior Full Stack Developer** with solid experience developing scalable and high-performance digital products. We value candidates with a strong focus on architecture, code quality, and experience working in distributed microservices-based environments. * **Frontend:** Solid experience with **React.js**, **Next.js**, and **TypeScript**, including reusable component development and design systems. * **Backend:** Development with **Node.js** and **NestJS**, microservices, and clean architectures (Hexagonal, DDD, BFF). * **Databases:** Proficiency with **PostgreSQL**, **MongoDB**, and use of **Redis** for caching. * **Infrastructure:** Experience with **Docker**, deployments on **AWS / GCP / Azure**, and observability tools (Grafana, Elastic). * **Distributed Systems:** Experience with **Kafka**, PubSub, and event-driven architectures. * **Testing:** Familiarity with Jest, Playwright, and quality best practices. * **AI (as a plus, not required):** Integration of AI APIs, frameworks such as LangGraph or Vercel AI. **What would your responsibilities be?** * Develop and evolve modern web interfaces using **React / Next.js**, with emphasis on performance and usability. * Design, build, and maintain microservices using **Node.js** and **NestJS**. * Participate in architectural decisions and contribute technical expertise to scalable projects. * Design and integrate messaging, caching, and persistence systems. * Collaborate on the creation and evolution of **design systems** and reusable components. * Contribute to platform observability through metrics, dashboards, and traceability. * Work alongside multidisciplinary teams (product, UX, backend, mobile). * Actively participate in code reviews, establish best practices, and drive continuous improvement of the tech stack. * (**Optional**) Integrate AI services into existing digital products when needed. **Additionally, we highly value experience and/or knowledge in:** * Prior experience developing **complex digital products**, B2C or high-traffic applications. * Experience in **performance optimization**, both frontend and backend. * Deep understanding of modern architectural patterns. * Experience with **event-driven architectures**. * Experience integrating cloud services (AWS, GCP, or Azure). * Strong grasp of **CI/CD**, automated testing (Jest, Playwright, RTL). * Ability to work in agile environments (Scrum/Kanban). **And with us, you’ll enjoy:** Full-time schedule of 8 hours per day (no compressed workweek) 2 remote workdays per week Flexible start time between **7:00 and 10:00**, plus **1 hour for lunch** Additional vacation days as compensation Hybrid on-site model: **minimum 3 days per week onsite in Madrid (Sanchinarro area)** At ***knowmad mood***, we are committed to equal opportunity and respect for diversity. We apply our Equality Plan and the principle of non-discrimination across all our recruitment processes. Stay updated on our news by following us here \-\> knowmad mood