Backend AI Engineer

Barcelona (hybrid)
Permanent contract
Salary: up to 62K


Role Overview

We are searching for a Backend AI Engineer who can combine strong backend engineering practices with the ability to bring AI systems into real production environments. In this role, you will design and operate the backend microservices that power advanced digital features for large-scale consumer applications.

Your work will involve connecting business logic, data pipelines, and AI-driven functionality into high-performing, secure systems. You will implement the APIs and services that allow AI models to deliver reliable user-facing experiences, ensuring scalability, consistency, and compliance at every step.

This role focuses on building the backend foundation that enables AI to work effectively in production: orchestrating microservices, integrating AI model lifecycles, creating evaluation and safety layers, and ensuring models improve through continuous feedback and structured tuning.

You will collaborate closely with AI, product, and data engineering teams, translating model insights into robust backend architecture while maintaining an emphasis on performance, observability, and operational excellence.

Key Responsibilities

• Oversee and refine model behavior by designing evaluation workflows, feedback mechanisms, and correction processes.
  
  

• Build and manage fine-tuning and retraining pipelines (SFT, LoRA, DPO), securely incorporating system and user feedback.
  
  

• Develop internal tooling for model assessment, including guardrails, moderation systems, and scoring frameworks.
  
  

• Embed model lifecycle operations into CI/CD pipelines, handling versioning, deployment, rollback, and monitoring.
  
  

• Partner with data and platform teams to ensure efficient model serving and scaling within Kubernetes environments.
  
  

• Transform insights from model performance into backend architectural improvements and optimizations.
  
  

Requirements

• 5+ years of experience in backend development using .NET Core / C#, Go, or Java.
  
  

• Demonstrated experience building and maintaining cloud-native applications and microservices (Kubernetes, Docker, Terraform, ArgoCD).
  
  

• Strong knowledge of API design, service interfaces, and observability technologies (OpenTelemetry, Prometheus).
  
  

• Hands-on experience integrating or operating LLM-based APIs (OpenAI, Azure OpenAI, Anthropic, etc.) in production settings.
  
  

• Solid understanding of CI/CD automation, testing strategies, and modern deployment workflows.
  
  

• Familiarity with data architectures including SQL/NoSQL storage, queues, and messaging systems.
  
  

• Ability to communicate clearly and collaborate effectively with both technical teams and product stakeholders.
  
  

Nice to Have

• Background in model evaluation, dataset curation, or AI lifecycle management.
  
  

• Experience using AI-assisted coding tools (Copilot, Cody, ChatGPT).
  
  

• Exposure to AI-driven approaches to code quality, refactoring, or automated testing.