Sergi – Kubernetes, RabbitMQ, Golang

A business messaging platform supporting WhatsApp Business and SMS, with configurable state-machine and AI chatbots for automating customer conversations. The platform integrates with external services to exchange data with user conversations, enabling businesses to build automated messaging workflows and service interactions.

State-Machine Chatbot & Multi-Channel Conversational System

• Ownership & Architecture: Owned the end-to-end design, development, and deployment of a high-throughput, Go-based conversational platform built on microservices architecture and running on Kubernetes. Acted as a core technical driver just below the tech lead, making key architectural decisions and defining system patterns for a small, agile engineering team.
• Distributed Systems & Challenges: Solved complex distributed state management challenges while acting as a real-time bridge connecting external messaging ecosystems (such as WhatsApp) with various client-facing backend systems. Engineered the system to handle concurrent event streams and ensure consistency across distributed boundaries.
• Performance & Impact: Tackled stringent real-time latency requirements, optimizing message processing pipelines to guarantee near-instant generation and delivery for end-users. Achieved 99.9% system uptime over the past year through robust Kubernetes orchestration, fault-tolerant design, and rigorous testing methodologies, operating reliably without dedicated weekend on-call rotations. Mentored junior engineers and conducted thorough code reviews to maintain high engineering standards.

AI Agents Service with Custom RAG (Azure Foundry & Azure AI Search)

• Ownership & Architecture: Drove the end-to-end architecture and implementation of a scalable AI agent service enabling customers to build and deploy custom Retrieval-Augmented Generation (RAG) agents powered by Azure Foundry and Azure AI Search.
• Technical Challenges & Optimization: Addressed complex retrieval and throughput challenges, orchestrating the integration between foundational LLM infrastructure and client-specific knowledge bases to deliver fast, context-aware answers.
• Concrete Impact: Spearheaded a major architectural redesign by transitioning the RAG infrastructure into a shared index architecture, successfully driving down infrastructure costs by nearly 90% while preserving response quality and low latency.

Core Web Application Frontend

• Development & Collaboration: Supported development of customer-facing frontend features for the core web application, ensuring a seamless, high-performance user experience that integrated tightly with the underlying Go microservices and AI agent backends.

A last-mile delivery platform that connects businesses with eco-friendly delivery partners across European cities. The platform helps businesses coordinate and manage sustainable delivery services through a network of local partners.

Routing & Planning Algorithm Microservice (Sustainable Last-Mile Delivery)

• Ownership & Architecture: Fully owned the end-to-end design, development, and deployment of the platform’s first standalone Go-based microservice, extracting core business logic out of a legacy Nest.js monolith. Acted as the engineering lead for the final year following the departure of the tech lead, driving architectural decisions and technical roadmap.
• Technical Challenges & Distributed Systems: Solved complex, highly constrained routing and optimization challenges tailored specifically for sustainable last-mile delivery operations using bike couriers carrying backpacks. Designed algorithmic models to handle multi-stop planning, dynamic scheduling constraints, and spatial efficiency.
• Concrete Scale & Impact: Successfully scaled the system during the COVID-19 pandemic, absorbing a greater than 1,000% surge in delivery volume with a lean team and limited rider capacity, while maintaining an exceptionally low non-delivery rate of under 2% within the first 24 hours.

Monolith Modernization & Database Migration (Node.js/Nest.js to Go & MongoDB)

• Architecture & Modernization: Spearheaded the strategic breakdown of a core Node.js/Nest.js backend monolith into a scalable, high-performance microservices architecture.
• Data Migration: Engineered and led a critical zero-downtime database migration transitioning the core application data layer from Firebase Firestore to MongoDB, significantly improving query flexibility, performance, and long-term data scalability.

AWS Infrastructure & Containerization Management

• Infrastructure Operations: Managed and scaled production AWS cloud infrastructure using Docker and Amazon ECS, ensuring high availability, fault tolerance, and seamless deployment cycles for high-traffic delivery windows.

Customer-Facing Frontend Features (Web & Mobile)

• Product Delivery: Developed key customer-facing features for both the core web application and mobile app, optimizing the delivery management dashboard and streamlining day-to-day operations for riders and dispatchers.

A build monitoring system implemented as a Grafana plugin to track the status of long-running software builds for medical diagnostic machines. The system provides visibility into build progress and status, helping teams monitor software releases for diagnostic equipment.

• Developed a build monitoring system as a Grafana plugin for tracking long-running software builds.
• Implemented monitoring and visualization of build status and progress within Grafana.
• Integrated build information into Grafana dashboards to provide clear visibility into ongoing builds.
• Supported monitoring of software builds used in medical diagnostic machines.

A social network for evaluating soft skills and providing insights into team dynamics in business environments. The platform helps organizations assess interpersonal skills and better understand collaboration within teams.

• Designed and implemented backend features for a social network focused on soft skills evaluations and team dynamics.
• Developed customer-facing frontend features for the core mobile application using Java for Android.
• Implemented features supporting soft skills evaluations and user interactions within the platform.
• Integrated frontend functionality with backend services to support core application workflows.