Senior AI Engineer

LexRoom Arbitration Support

. Design and build agent-driven and RAG-based AI systems for complex legal tasks .

Posted 10/22/2026full-timeBarcelona • SpainSenior💰 €70,000 - €100,000 per yearWebsite

Core Competencies

Role fit

Core Competencies

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Demonstrates expertise in designing and building AI systems for legal tasks, with a strong focus on fine-tuning LLMs and optimizing ML pipelines. Proficient in implementing NLP algorithms and collaborating with legal experts to enhance evaluation protocols and datasets.

Highest-signal resume keywords

Python ProgrammingML Pipeline ManagementLLM Research ExperienceNLP Algorithm ImplementationMLOps Familiarity

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills

Machine LearningReinforcement LearningSupervised LearningNLP AlgorithmsSearch TechnologiesLarge-Scale Retrieval SystemsDeep Learning SystemsPerformance EvaluationData StructuringLegal Document Processing

Soft Skills

CollaborationCommunication

Tools & Technologies

Vector DatabasesFull-Text SearchML Models Integration

Industry Keywords

Legal AI SystemsDomain-Specific DatasetsEnd-to-End EvaluationsCoding StandardsCode Review Processes

Tech Stack

Tools & technologies

Python

About the role

Key responsibilities & impact

Design and build agent-driven and RAG-based AI systems for complex legal tasks
Fine-tune and post-train LLMs using supervised and reinforcement learning techniques
Develop and optimize large-scale search pipelines for LLM-powered agents
Implement and refine NLP algorithms for extracting, structuring, and validating legal-document information
Run end-to-end evaluations to identify bottlenecks, measure performance, and guide improvements
Work with legal experts to design evaluation protocols and build domain-specific datasets
Follow coding standards, best practices, and rigorous code-review processes

Requirements

What you’ll need

Proven expertise building and managing robust ML pipelines
Strong Python skills
Hands-on experience in LLM research and deep learning systems
Knowledge of search technologies, including full-text search, vector databases, or large-scale retrieval systems
Familiarity with MLOps and integrating ML models into production backends (a strong plus)
Up-to-date knowledge of LLM innovation
Ideally, experience in pre-training or deploying large-scale models in real-world scenarios
Fluency in English, written and spoken
Knowledge of Italian is a plus

Benefits

Comp & perks

Equity package
Hybrid work with remote-work flexibility
Comprehensive health insurance
Meal vouchers
Performance bonuses tied to measurable results
Team retreats and off-sites
Opportunities to grow and lead high-stakes projects