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Full-Stack JavaScript Engineer

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Yopeso

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Location:
Spain , Madrid

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Category:
IT - Software Development

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Contract Type:
Not provided

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Salary:

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Job Description:

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.

Job Responsibility:

  • 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

Requirements:

  • 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

Additional Information:

Job Posted:
April 16, 2026

Work Type:
Hybrid work
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