Julian Ortega

Staff Engineer, Search, Recommendations & AI Platforms

Building agentic AI, conversational, and recommendation systems at Fredhopper

Staff Engineer with 15 years building recommendation and personalization systems at scale. From my MSc thesis on hybrid recommenders to production services adopted by 30+ enterprise retailers across 40+ languages, I own ranking systems end-to-end: problem framing, data exploration, model design, online serving, A/B experimentation, and iteration.

I take ambiguous technical bets from prototype to production. I built the original Adaptive Personalization Engine from PoC through four production releases. I led the AI-powered semantic search platform serving billions of queries across fashion, sports, grocery, and DIY verticals. Most recently I evolved a conversational commerce product from research to production with a single-agent-with-tools architecture at 20x lower LLM cost.

I am fluent with AI-assisted development and use Claude Code daily. I care about craft, autonomy, and shipping. I believe the best ML engineers understand the full stack from user need to production system.

Amsterdam, Netherlands EU Citizen
Spanish Native English Professional C2
Open to talk
LinkedIn GitHub
Julian Ortega - Profile Photo
Recommendations & Personalization
  • Hybrid recommender system MSc thesis with matrix factorization, demonstrating up to 6% AUC improvement over collaborative filtering baselines
  • Built Adaptive Personalization Engine from PoC to production across 4 releases, processing 200+ events/second
  • AI-powered semantic search adopted by 30+ enterprise retailers across 40+ languages
Generative & Agentic ML
  • Evolved conversational commerce to production with single-agent-with-tools architecture at 20x lower LLM cost
  • Built AI knowledge assistants targeting ~18% of support ticket volume, validating ~80% documentation coverage
  • Active Claude Code user; piloted AI code assistant tools across 15 engineers
Prototype to Production
  • Took ambiguous technical bets from research prototype to production across recommendations, search, and agentic systems
  • Architected K8s migration for 500+ server fleet with zero changes to upstream systems
  • 84% test coverage on search microservice; production systems handling 100x traffic spikes

Technical Skills

Expert Advanced Proficient
Recommendations, Personalization & ML
Recommendation Systems Personalization Systems Ranking Systems Collaborative Filtering Embedding Models Vector Search Semantic Search Matrix Factorization Information Retrieval A/B Testing & Experimentation Evaluation Metrics (nDCG, MAP, AUC, R-Precision) Machine Learning Deep Learning Neural Networks
Generative & Agentic ML
LLMs Agentic AI Systems Conversational AI RAG MCP Prompt Engineering AI-Assisted Development (Claude Code) Multimodal LLMs (Gemini, Vertex AI)
Programming & Development
Python Java RESTful APIs SQL FastAPI gRPC OpenAPI TDD Scala
ML Infrastructure & Data
Docker Elasticsearch / Lucene Kubernetes (GKE) GCP AWS CI/CD Helm ArgoCD / Argo Workflows Kafka Apache Storm ETL Pipelines & Feature Pipelines PostgreSQL Prometheus & Monitoring Real-time Model Serving Terraform Apache Spark DynamoDB Redis
Leadership & Craft
Mentoring Cross-functional Collaboration Stakeholder Management Software Architecture System Design Microservices Technical Vision Distributed Systems Performance Optimization

Professional Experience

December 2025 - Present

Staff Engineer

Rezolve Ai (Fredhopper B.V.)
Amsterdam, Netherlands
Staff Engineer in the Product Discovery team, continuing agentic AI and recommendation workloads while leading infrastructure modernization initiatives across multiple engineering teams.
  • Designed Kubernetes migration architecture for a core search service of 500+ servers, building a working PoC that required zero downtime or changes to upstream systems
  • Continuing development of agentic AI products and cross-team technical leadership on recommendation and discovery systems
Python Java LLMs Agentic Systems Kubernetes ArgoCD Argo Workflows Helm Docker AWS Microservices Event-Driven Architecture
January 2025 - November 2025

Staff Engineer

Crownpeak (Fredhopper B.V.)
Amsterdam, Netherlands
Led three product initiatives spanning generative ML, ranking systems, and conversational agents. Took ambiguous technical bets from research through production with measurable business outcomes.
  • Evolved conversational commerce from research to production, adopting a single-agent-with-tools architecture at 20x lower LLM cost than the initial vendor, validated as the pattern later adopted by leading AI providers
  • Built AI knowledge assistants targeting ~18% of all support ticket volume, with internal trial validating ~80% documentation coverage and a 30% ticket deflection target
  • Led architectural redesign of the suggestion ranking system, reducing index processing times by 64-93% and improving suggestion relevance by 15-18% in customer quality testing
  • Contributed to AI-powered synonym generation system achieving 93% human-level accuracy in early customer testing
  • Owned service lifecycle end-to-end: model deployment, real-time inference monitoring, CI/CD, evaluation metrics, and cross-functional delivery with product, sales, and customer success
Python Java FastAPI LLMs Generative AI RAG Agentic Systems MCP Dify Langgraph Gemini OpenAI AWS Bedrock Vertex AI Conversational AI Vector Search Semantic Search Lucene Kubernetes ArgoCD Docker Microservices Evaluation Metrics Real-time Inference
Apr 2020 - Dec 2024

Software Architect

Attraqt (Fredhopper B.V.)
Amsterdam, Netherlands
Architected the AI Search programme across text search, visual recommendations, product tagging, autocomplete, and reverse image search. Led technology transfer from an acquired AI company, delivering a hybrid search engine combining vector and traditional search, and an AI Search plugin using shared embedding technology for vector-based retrieval.
  • Architected AI-powered semantic search adopted by enterprise retailers across fashion, sports, grocery, and DIY verticals, supporting 40+ languages
  • Led vector search scaling investigation across 4 backends, identifying the cost-viable architecture for enterprise-scale catalogues
  • Built serving infrastructure handling 100x traffic spikes through autoscaling architecture validated during production incidents
  • Drove CI/CD optimization delivering 3x build speedup at lower infrastructure cost across the engineering organization
  • Founded the Software Architecture Group, establishing engineering standards, code quality analysis across 5 product lines and 2M+ lines of code, and a 7-level dual-track career ladder
Python Java Kotlin Scala Neural Networks Deep Learning Vector Search Semantic Search Embedding Models Elasticsearch OpenSearch GKE GCP gRPC Microservices Distributed Systems Information Retrieval Recommendation Systems
Apr 2016 - Apr 2020

Team Leader / Line Manager

Attraqt (Fredhopper B.V.)
Amsterdam, Netherlands
Led development teams of 3-5 engineers while driving two major platform initiatives: the Adaptive Personalization Engine and the Search Modernization project. Championed cloud-native technologies, experimentation, and modern engineering practices.
  • Designed and led implementation of the Adaptive Personalization Engine (APE) from PoC to production, building a microservices architecture with 6 core components processing real-time user activity streams at 200+ events/second across 4 major releases
  • Delivered personalized product recommendations and search re-ranking while maintaining search response impact under 50ms average
  • Initiated and led the search modernization project, reducing reindex times from 2+ hours to 26 minutes and improving search response from 192ms to 130ms; achieved 99.8% of queries under 200ms
  • Coordinated cross-functional delivery across 8+ stakeholder teams including operations, infrastructure, QA, sales, and professional services
  • Mentored junior developers and facilitated career growth, with 70% of team members receiving promotions during tenure
Java Python Apache Storm Apache Kafka Apache Spark Kubernetes Docker AWS DynamoDB Elasticsearch Collaborative Filtering A/B Testing Experimental Design Microservices Snowplow Analytics
Apr 2015 - Apr 2016

Senior Software Engineer

SDL (Fredhopper B.V.)
Amsterdam, Netherlands
Senior Software Engineer focused on developing e-commerce search and recommendation solutions while bridging research and practical implementation.
  • Created real-time recommendations engine proof of concept, integrating it into the core e-commerce product and establishing the foundation for production recommendation systems
  • Optimized product catalog ETL processes for 32M+ product catalogues, reducing reindexing time from 40 hours to 4 hours through data partitioning and performance improvements
  • Led major upgrade of internal ETL framework spanning 4 major platform versions, enabling the Data team with modern tooling
  • Developed ETL processes for user profile indices used in personalized merchandising
Java Pentaho PDI ETL Optimization Real-time Systems Machine Learning Recommendation Systems
May 2012 - Apr 2015

Software Engineer

SDL (Fredhopper B.V.)
Amsterdam, Netherlands
Software Engineer working on search and recommendation technologies while contributing to research and development initiatives.
  • Developed and maintained search and recommendation algorithms processing terabytes of e-commerce data
  • Implemented collaborative filtering techniques that improved recommendation accuracy across multiple client implementations
  • Worked on large-scale data processing systems, optimizing performance for real-time recommendation delivery
Java Collaborative Filtering Recommendation Systems Data Processing
Nov 2011 - Apr 2012

R&D Intern

Fredhopper B.V.
Amsterdam, Netherlands
Research and Development internship focusing on recommendation systems and collaborative filtering while contributing to academic research.
  • Automated and industrialized evaluation process of recommendations, creating frameworks still used in production systems
  • Generated new recommendation approaches based on collaborative filtering, contributing to patent applications
  • Researched machine learning techniques for recommendation systems, bridging academic research with commercial applications
Machine Learning Collaborative Filtering Recommendation Systems Research

Key Projects

2016-2018

Adaptive Personalization Engine (PoC to Production)

Created the initial proof of concept and led the evolution from research prototype to production platform across 4 major releases. Designed a real-time personalization system that tracked user interactions, built behavioral profiles, and delivered personalized product recommendations and search re-ranking for e-commerce retailers.
  • Created the original proof of concept and evolved it to production across 4 major releases over 2.5 years
  • Built microservices architecture with 6 core components processing real-time user activity streams at 200+ events/second
  • Maintained search response time impact under 50ms average while delivering personalized recommendations
  • Coordinated cross-functional delivery across 8+ stakeholder teams
Java Python Apache Storm Apache Kafka Kubernetes Docker AWS DynamoDB Elasticsearch Collaborative Filtering A/B Testing Microservices Snowplow Analytics Real-time Inference
2020-2023

AI-Powered Semantic Search Platform

Pioneered AI-powered semantic search capabilities across two product lines: a standalone hybrid search engine combining vector and traditional search, and an AI Search plugin for the existing e-commerce platform using the same embedding technology for vector-based retrieval. Led technical architecture, technology transfer from an acquired AI company, and scaling to enterprise catalogues.
  • Adopted by enterprise retailers across fashion, sports, grocery, and DIY verticals, supporting 40+ languages
  • Led vector search scaling investigation across 4 backends, identifying the cost-viable architecture for enterprise-scale catalogues
  • Architected dual delivery model: standalone hybrid search engine and AI Search plugin using shared embedding technology
  • Handled 100x traffic spikes through autoscaling architecture validated during production incidents
Python Kotlin Neural Networks Deep Learning Embedding Models Vector Search Semantic Search Information Retrieval Elasticsearch OpenSearch GKE gRPC Distributed Systems
2024-2025

Conversational Commerce Platform (Agentic ML)

Designed the technical architecture and built the core integration layer for a conversational shopping assistant. Evolved from research prototype to production deployment with a single-agent-with-tools architecture, selected across LLM providers to balance cost, latency, and reasoning quality.
  • Self-initiated from research through PoC to production deployment, providing a narrative and live demo that supported new prospect engagement
  • Evolved architecture from modular intent routing to a single-agent-with-tools pattern with templated prompts and emotional tone adaptation, later validated as the approach adopted by leading AI providers
  • Evaluated LLM providers and reached a 20x lower cost than the initial vendor, with gains in intelligence, tool use, and speed
  • Built tools and infrastructure to allow agents to reason using customer search and merchandising engines
Python Java FastAPI MCP OpenAPI LLMs Gemini OpenAI AWS Bedrock Vertex AI Conversational AI Dify Langgraph Kubernetes Microservices
2025

AI-Powered Knowledge Assistants (RAG + Agentic)

Designed and built a dual-purpose AI assistant system for customer self-service and support agent enablement. Architected knowledge processing pipeline to crawl, transform, and embed documentation and anonymized historical ticket data into a searchable vector knowledge base with LLM-powered conversational interface and tool-calling capabilities.
  • Targeted the largest addressable support category (~18% of all ticket volume), reducing resolution friction for common how-to questions
  • Internal trial validated ~80% documentation coverage for real customer questions
  • Designed for measurable ticket deflection with a 30% reduction target, directly reducing average resolution times of 20+ days
  • Processed and embedded ~900 knowledge base pages and anonymized customer tickets into the retrieval pipeline
Python Generative AI LLMs RAG Vertex AI FastAPI MCP Vector Search Semantic Search Conversational AI Evaluation Metrics
2018-2020

Search Modernization Project

Modernized the company's core search engine from a monolithic Lucene-based architecture to a cloud-native Elasticsearch microservice, serving 200+ international retailers processing billions of queries annually across catalogues with millions of items.
  • Reduced search reindex times from 2+ hours to 26 minutes across three release iterations
  • Achieved 99.8% of queries under 200ms for mid-size catalogues
  • Improved average search response from 192ms to 130ms on the platform's most demanding deployment
  • Delivered 84% test coverage across unit and integration tests
  • Architected hot-swap reindex strategy enabling zero-downtime index updates
Java Spring Boot Elasticsearch Lucene Kubernetes Docker AWS Microservices ELK Stack Grafana

Academic Background

2013 - 2015

Master's in Computer Science (AI Specialization)

Vrije Universiteit Amsterdam (VU Amsterdam)
Amsterdam, Netherlands
Curriculum: Specialized in Artificial Intelligence, Machine Learning, recommendation systems, and information retrieval.
Thesis: Developed and evaluated a hybrid recommender system using matrix factorization with alternating least squares (ALS) to assess the impact of integrating multiple data types (user interactions, product metadata, demographics) on e-commerce recommendation accuracy. Conducted comparative analysis across four datasets using standard IR metrics (R-Precision, nDCG, MAP, AUC), demonstrating up to 6% AUC improvement over baseline collaborative filtering.
2005 - 2010

B.S. in Systems Engineering

Universidad EAFIT
Medellín, Colombia
Curriculum: Software engineering, statistical methods, parallel computing, data structures.
Thesis: Implemented and optimized parallel AES encryption algorithms on multi-core CPUs and GPUs, achieving up to 19x acceleration with CUDA, contributing to high-performance computing for real-world applications.

Certifications

Neural Networks and Deep Learning
Coursera (deeplearning.ai), Sep 2017
Improving Deep Neural Networks: Hyperparameter Tuning, Regularization and Optimization
Coursera (deeplearning.ai), Sep 2017
Machine Learning
Coursera (Stanford), Oct 2012
Introduction to Data Science
Coursera, Jun 2013
The Data Scientist's Toolbox
Coursera, Mar 2015
Effective Programming in Scala
École Polytechnique Fédérale de Lausanne, Feb 2024

Publications

Parallelizing AES on Multicores and GPUs

Julian Ortega, Christian Trefftz, Helmuth Trefftz
Parallelized AES block cipher on multi-core microprocessors and GPUs using OpenMP and CUDA, demonstrating GPU speedups up to 19x for encryption-specific operations.
View Publication

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