Logo
Javier – RAG, LLM, Python, experts in Lemon.io

Javier

From Colombia (UTC-5)flag

AI Engineer|Middle-to-senior
Back-end Web Developer|Middle-to-senior

Javier – RAG, LLM, Python

Andres is a Middle-to-Senior Backend and AI Engineer with 10+ years of experience building scalable systems using Java, Python, and cloud technologies. His background covers finance, healthcare, logistics, and enterprise solutions, including system migrations, integrations, and greenfield development. In recent years, Andres has worked with AI-enabled applications, focusing on RAG architectures, embeddings, vector databases, and agent workflows for document processing solutions. He brings strong architectural thinking, clear communication, and experience collaborating across remote and consulting environments.

11 years of commercial experience in
Entertainment
Fintech
Main technologies
RAG
2 years
LLM
2 years
Python
6 years
LangChain
2 years
LangGraph
2 years
Pinecone
2 years
Additional skills
AI agent development
AWS
Cloud Computing
GCP
Direct hire
Possible
Ready to get matched with vetted developers fast?
Let’s get started today!

Experience Highlights

Senior Backend Software Engineer
Apr 2021 - Ongoing5 years 2 months
Project Overview

A cloud-native logistics platform for modernizing legacy systems through scalable microservices, Kubernetes-based deployments, event-driven shipment processing, and RAG-powered semantic retrieval.

Responsibilities:
  • Contributed to the migration of legacy on-premise features into cloud-native microservices deployed on Google Kubernetes Engine (GKE), helping improve scalability and operational reliability;
  • Collaborated closely with Product and integration teams to refine requirements and ensure successful end-to-end feature delivery from development to pre-production environments;
  • Participated in architectural discussions to align new services with distributed systems best practices and internal cloud guidelines;
  • Stored and indexed embeddings in Elasticsearch vector search to support semantic retrieval as part of a Retrieval-Augmented Generation (RAG) workflow, enabling relevant context to be retrieved and provided to LLMs;
  • Implemented high-performance backend services using Java 21, JAX-RS, JPA/Hibernate, and WebSphere Liberty, ensuring clean design and maintainability;
  • Designed event-driven processing for shipment lifecycle events using Pub/Sub;
  • Contributed to CI/CD processes using TeamCity and Octopus, supporting reliable deployments to GCP-based Kubernetes environments;
  • Generated semantic embeddings using Python-based services and managed batch processing for large volumes of enterprise data;
  • Ensured high-throughput, idempotent, and scalable EDI status delivery.
  • Investigated and resolved production issues, focusing on performance optimization and system stability;
  • Worked within Scrum-based agile teams, participating in planning, refinement, and cross-team synchronization meetings to ensure alignment with business objectives.
Project Tech stack:
Java
Python
RAG
Vector Databases
AI agent development
AI agent orchestration
Multi-Agent Systems
Microservices
MCP
MCP Server
AI API integration
Senior Backend Software Engineer
Apr 2021 - May 20265 years 1 month
Project Overview

An enterprise backend platform built on a scalable microservices architecture, combining event-driven communication, AWS cloud infrastructure, and AI-powered document intelligence through RAG workflows and LLM-based agents.

Responsibilities:
  • Participated in system design discussions and translated product requirements into scalable backend solutions, ensuring alignment through proper technical documentation and implementation guidelines;
  • Designed and implemented microservices following Clean Architecture and Domain-Driven Design (DDD) principles;
  • Addressed a race condition scenario in a third-party authentication flow by introducing Kafka as a distributed broker to serialize requests and Redis as a caching layer to improve consistency and performance;
  • Implemented event-driven communication using webhooks in a distributed microservices architecture to handle asynchronous client responses;
  • Designed a scalable processing strategy for a microservice by leveraging AWS SQS, Lambda functions, and EventBridge to dynamically schedule and control workload processing;
  • Added observability to microservices by integrating Micrometer (MeterRegistry) with AWS CloudWatch for metrics collection and monitoring;
  • Implemented Retrieval-Augmented Generation (RAG) architectures using embeddings and vector storage to enable contextual data access across internal systems;
  • Contributed to DevOps processes, including CloudFormation templates and Jenkins pipeline configuration for CI/CD automation;
  • Built a document processing service using Quarkus and Mutiny to handle OCR workflows, exposing metrics through Micrometer and CloudWatch;
  • Designed and implemented an MCP Server to enable intelligent document management for semantic indexing (embeddings) and contextual retrieval capabilities, allowing LLM-based agents to query, reason, and interact with enterprise documents in a secure and scalable manner;
  • Ensured performance considerations and DevOps best practices were incorporated throughout the development lifecycle;
  • Worked within Scrum-based agile teams, contributing to iterative delivery and cross-functional collaboration.
Project Tech stack:
Java
Python
RAG
AI agent development
AI agent orchestration
Multi-Agent Systems
Amazon ECS
AWS
Microservices
DynamoDB
Kafka
Hibernate
Spring Boot
Amazon SQS
Amazon SNS
Bedrock
Redis
Docker
PostgreSQL
JPA
Senior Backend Software Engineer
Dec 2020 - Aug 20254 years 7 months
Project Overview

A cloud-native backend platform focused on scalable architecture, secure payment processing, and reliable transaction handling through event-driven communication, serverless infrastructure, and containerized deployments.

Responsibilities:
  • Defined backend architecture strategy leveraging Clean Architecture to decouple domain logic from infrastructure concerns;
  • Designed event-driven communication patterns using AWS SNS/SQS and serverless compute with Lambda to improve scalability and cost-efficiency;
  • Led the integration of external payment services (Stripe), ensuring secure transaction handling and fault tolerance;
  • Modernized legacy modules and aligned them with cloud-native and containerized deployment standards;
  • Established deployment workflows across environments and ensured production-grade reliability;
  • Acted as a technical reference for architectural decisions and implementation patterns.
Project Tech stack:
Java
AI API integration
Python
Spring Boot
JPA
Hibernate
MySQL
AWS
AWS Lambda
Amazon SNS
Amazon SQS
Docker
Flyway
Stripe API
Senior Software Engineer
Apr 2019 - Apr 20212 years
Project Overview

A cloud-native time and attendance platform for workforce scheduling and tracking, built with microservices and event-driven architecture to support large-scale operations and high-volume data processing.

Responsibilities:
  • Contributed to architectural direction of a cloud-native, event-driven platform leveraging Pub/Sub and serverless patterns to support high-throughput processing;
  • Designed scalable microservices using Event Sourcing and DDD principles, enabling reliable state reconstruction and domain consistency;
  • Led migration of legacy scheduling systems to Kubernetes and GCP-based serverless workloads, handling 500K+ records in minutes through optimized concurrency strategies;
  • Defined horizontal scaling strategies (Kubernetes RPS-based autoscaling and event-driven Lambda orchestration);
  • Established distributed system best practices including JWT asymmetric authentication, observability (Splunk), and multithreaded processing standards;
  • Mentored engineers and influenced cross-team architectural decisions in a microservices ecosystem.
Project Tech stack:
Java
Python
AWS
Docker
Kafka
Spring
Microservices
Kubernetes
Clean Architecture
GCP
Spring Boot
JUnit
Splunk

Education

2015
Systems engineering
Systems engineer

Languages

English
Advanced

Hire Javier or someone with similar qualifications in days
All developers are ready for interview and are are just waiting for your requestdream dev illustration
Copyright © 2026 lemon.io. All rights reserved.