Senior Fullstack Engineer in Madrid/Barcelona (remote) for an International client Job role: Senior Fullstack Software Engineer Job description:A Senior Fullstack Software Engineer with high experience in DevOps, Kubernetes & Python. Location: Madrid/Barcelona (Remote) Languages required: English (C1) MANDATORY Minimum experience:5 to 7 years Rate:260-285€/day DESCRIPTION Responsibilities: We are seeking a Senior Fullstack Software Engineer with strong expertise in Python and solid experience in JavaScript (preferably ReactJS). The ideal candidate will take a lead role in backend architecture and development with a strong emphasis on performance, reliability, and scalability, supporting thousands of concurrent users and high-frequency external integrations. The role includes contributing to frontend development with modern technologies, making key technical decisions, driving architectural improvements, ensuring high code quality through comprehensive testing (including Playwright for end-to-end and integration tests), and collaborating with engineering and product stakeholders. This position requires hands-on experience with our technology stack and a proactive, improvement-oriented mindset. Knowledge and Skills: • Lead backend architecture and development to ensure high performance, scalability, and reliability. • Develop and maintain backend services using Python and FastAPI. • Contribute to frontend development using ReactJS, Typescript, Vite, and Tailwind. • Drive technical decision-making and promote best practices across the engineering team. • Collaborate closely with engineers, product managers, and stakeholders to deliver robust and user-friendly solutions. • Participate in architectural reviews and contribute to continuous improvement initiatives. • Work with databases and storage technologies such as Redis, and manage migrations with Alembic. • Coordinate with the infrastructure team regarding deployments and operations in environments using Azure DevOps, Docker, Kubernetes, and AWS. Technical Skills: • Python (5+ years) • FastAPI • JavaScript / Typescript • ReactJS (3+ years preferred) • Typescript • Tailwind • Vite • Redis • Alembic (migrations) • Azure DevOps • MongoDB • PostgreSQL • Docker • Kubernetes • AWS • (Infrastructure knowledge is a plus but not mandatory) Languages: • English (C1) Rate: • 260-285€/day. Originally posted on Himalayas