Full Stack Engineer – Node.js & React

About the role

NUMBERO, a German tech startup transforming after‑sales processes for car dealerships, is seeking a Full Stack Engineer to join its Valencia development hub. You will work on a production‑grade Node.js backend and a React + TypeScript frontend, integrating data and AI services that power intelligent insights for automotive clients.

Key responsibilities

• Develop and maintain full‑stack features using React + TypeScript (frontend) and Express.js + TypeScript (backend).
• Design database schemas, write migrations and optimise MySQL/MariaDB queries.
• Build and expose REST APIs, integrate them with the UI and external data platforms.
• Implement background job processing, scheduled tasks and asynchronous workflows (e.g., BullMQ).
• Contribute to AI‑driven features, LLM integrations and prompt engineering.
• Integrate applications with PowerBI, Databricks and Azure Data Lake Storage.
• Ensure code is secure, scalable, well‑tested and reviewed.
• Monitor, debug and support production systems independently.

Required profile

• Strong ownership mindset, able to deliver end‑to‑end features without close supervision.
• Comfortable working across both frontend and backend layers.
• Effective communicator with technical and business stakeholders.

Required skills

• React, TypeScript, HTML5, CSS3 (Bootstrap, Tailwind CSS)
• Node.js, Express.js
• MySQL / MariaDB (schema design, query optimisation, migrations)
• Redis, BullMQ (or similar queue system)
• Docker, Docker Compose
• JWT authentication, role‑based access control
• Cron job scheduling
• Databricks, Azure Data Lake Storage, PowerBI
• REST API design and consumption, Git version control