We are seeking an experienced Full Stack Developer to join our team working on an open-source AI chat platform. The successful candidate will contribute to developing and maintaining a sophisticated conversational AI application that integrates multiple AI providers and offers a rich user experience, while collaborating closely with product and design stakeholders.

Key Responsibilities:

• Develop and maintain both frontend and backend components of the AI chat platform

• Implement new AI provider integrations and chat functionalities

• Work with modern React-based frontend and Node.js/Express backend architecture

• Collaborate on database design and optimization using MongoDB

• Implement and maintain real-time features using WebSocket connections

• Write comprehensive tests and ensure code quality through automated testing

• Deploy and maintain containerized applications using Docker

• Participate in code reviews and maintain high development standards

Required Technical Skills:

Frontend Development:

• React.js (v18+) with modern hooks and functional components

• TypeScript for type-safe development

• Vite for build tooling and development server

• TailwindCSS for styling and responsive design

• Radix UI and Headless UI for accessible component libraries

• Tanstack Query (React Query) for data fetching and state management

• React Router for client-side routing

• State management with modern React patterns

Backend Development:

• Node.js (v18+) with Express.js framework

• MongoDB with Mongoose ODM for database operations

• PostgreSQL structured data storage

• Redis for caching and session management

• RESTful API design and implementation

• JWT and session-based authentication

DevOps & Infrastructure:

• Docker and Docker Compose for containerization

• MongoDB database administration

• Environment configuration and secrets management

Development Tools:

• Git with advanced workflows (rebasing, merging, conflict resolution)

• ESLint and Prettier for code quality

Required Experience:

• 3+ years of full-stack JavaScript/TypeScript development

• Fluent in English, both written and verbal

• Excellent communication and collaboration skills

• Ability to work independently and manage complex projects

Nice to Have:

• Experience with OpenAI API, Anthropic Claude, or similar LLM APIs

• Understanding of prompt engineering and AI model integration

• LangChain framework for AI application development

• RAG (Retrieval-Augmented Generation) implementation experience

Work Arrangement:

Availability to work on-site from our Madrid office a few days per week, with the rest of the time remote.