Senior Full Stack Engineer – React & Node.js

Description

Job Summary: We are seeking a Senior Full Stack Developer with solid experience in developing scalable, high-performance digital products, with a focus on architecture and code quality. Key Responsibilities: 1. Develop and evolve modern web interfaces with a focus on performance. 2. Design, build, and maintain microservices in Node.js and NestJS. 3. Participate in architectural decisions and provide technical judgment. 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 the mission of delivering value to our clients and empowering our talent. Composed of over 3,000 creative, digital, and innovative individuals united 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—while 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, high-performance digital products. We value candidates with an architectural mindset, strong code quality awareness, and the ability to work in distributed, microservice-based environments. * **Frontend:** Solid experience with **React.js**, **Next.js**, and **TypeScript**, including building reusable components and design systems. * **Backend:** Development using **Node.js** and **NestJS**, microservices, and clean architectures (Hexagonal, DDD, BFF). * **Databases:** Proficiency with **PostgreSQL**, **MongoDB**, and using **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 in **React / Next.js**, emphasizing performance and usability. * Design, build, and maintain microservices in **Node.js** and **NestJS**. * Participate in architectural decisions and contribute technical judgment to scalable projects. * Design and integrate messaging, caching, and persistence systems. * Collaborate on creating and evolving **design systems** and reusable components. * Contribute to platform observability via metrics, dashboards, and traceability. * Work alongside multidisciplinary teams (product, UX, backend, mobile). * Actively participate in code reviews, establishing best practices and continuously improving 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 can 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 onsite model: **minimum 3 days per week onsite in Madrid (Sanchinarro area)** At ***knowmad mood***, we commit to equal opportunities and respect for diversity. We implement 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