Senior Full Stack Engineer (PythonJS)

The difference between software that works and software that lasts is the depth of its foundations. The Senior Full Stack Engineer (Python/JS) role in Barcelona is about building dependable systems that support growth and decision-making. This is a place for engineers who see the value in robust architecture and trusted data. You decide how technical choices shape the reliability and future of the platform. The person in this role sets the standard for what dependable software means.

• Build and maintain production-grade systems from scratch including backend services APIs data/ML platforms and automation
• Design and develop APIs using REST FastAPI GraphQL and/or gRPC
• Architect cloud-native serverless microservices and event-driven systems and ensure cloud integration (GCP and/or AWS)
• Implement DevOps practices including CI/CD Docker Kubernetes Terraform/IaC and automated deployments
• Apply security-aware engineering including IAM least privilege secrets management OIDC Entra ID and permissions management
• Lead technical design and mentor engineers communicating effectively with technical and business stakeholders
• Develop frontend/web applications for internal tools dashboards and proof of concepts
• Work with relational and NoSQL databases such as PostgreSQL Redis BigQuery and DynamoDB
• Ensure observability and debugging using CloudWatch Grafana Datadog or similar tools
• Contribute to building AI/ML platforms agentic AI systems agents chatbots RAG and LLM-based

• Expertise in software engineering fundamentals and building production-grade systems
• Proficiency in Python backend development including APIs services data/ML platforms and automation
• Experience with API development (REST FastAPI GraphQL and/or gRPC) and architecture skills across cloud-native serverless microservices and event-driven systems
• Cloud experience (preferably GCP and/or AWS) including ECS Lambda SNS SQS and managed data services
• Solid DevOps background: CI/CD Docker Kubernetes Terraform/IaC and automated deployments
• Security-aware engineering: IAM least privilege secrets management OIDC Entra ID and permissions management
• Experience with AI-assisted programming tools and modern engineering workflows
• Ability to lead technical design mentor engineers and communicate effectively with technical and business stakeholders
• Frontend/web app development experience especially for internal tools dashboards and proof of concepts
• Database experience across relational and NoSQL systems (PostgreSQL Redis BigQuery DynamoDB)

• Experience with LangChain LangGraph LlamaIndex and prompt engineering
• Platform engineering or developer experience background
• MLOps experience: model deployment inferencing monitoring and production operations