MENDES DOS SANTOS Alexandre

Jan 2024 - Aug 2024

National railway ticketing platform serving 15M+ monthly active users

• Architected and implemented serverless microservices for real-time train booking and seat reservation systems using AWS Lambda, API Gateway, and DynamoDB
• Led the migration of legacy monolithic ticketing services to event-driven architecture using AWS EventBridge and SQS, reducing latency and improving system resilience
• Designed and developed RESTful APIs for multi-modal transportation integration (train, bus, car-sharing), implementing circuit breakers and retry patterns for third-party service reliability
• Implemented Infrastructure as Code using AWS CDK and CloudFormation, automating deployment pipelines and reducing deployment time from hours to minutes
• Optimized DynamoDB data models and query patterns, achieving sub-100ms response times for complex journey searches across millions of route combinations
• Built real-time pricing engine with dynamic fare calculation based on demand, time, and availability using AWS Step Functions for complex workflow orchestration
• Established comprehensive monitoring and alerting using CloudWatch and X-Ray, improving incident detection time
• Collaborated with cross-functional teams in a fully remote environment, participating in architecture reviews and mentoring junior developers

Tech Stack: Node.js/TypeScript, AWS Lambda, DynamoDB, API Gateway, EventBridge, Step Functions, CDK, CloudFormation

Mar 2023 - Nov 2023

Digital transformation for major Swiss banking institutions

• Developed high-performance microservices for real-time payment processing and transaction validation
• Implemented distributed transaction patterns using Saga orchestration for complex multi-service operations ensuring ACID compliance across microservices
• Built secure API gateway layer with Spring Cloud Gateway, implementing rate limiting, request validation, and OAuth2/JWT authentication for PSD2 compliance
• Designed and implemented event sourcing architecture using Apache Kafka for audit logging and transaction history
• Optimized database queries and implemented caching strategies with Redis, reducing average API response time
• Developed automated reconciliation service for cross-border payments using Spring Batch, processing nightly batches
• Implemented comprehensive unit and integration testing, using JUnit 5, Mockito, and TestContainers
• Participated in on-call rotation, resolving production incidents and performing root cause analysis

Tech Stack: Java 17, Spring Boot, Spring Cloud, Apache Kafka, PostgreSQL, Redis, Docker, Kubernetes, GitLab CI/CD

May 2021 - Jan 2023

Wealth Management platform modernization

• Led backend development for COBOL-to-Java migration project, re-architecting legacy systems into modern microservices serving wealth management advisors
• Designed RESTful APIs for portfolio management, risk assessment, and regulatory reporting modules using Spring Boot and Hibernate
• Implemented complex business logic for investment portfolio rebalancing and tax optimization algorithms
• Built integration layer for real-time market data feeds processing price updates daily
• Developed Angular-based admin dashboard for system monitoring and configuration management
• Established CI/CD pipelines using Jenkins and SonarQube, improving code quality metrics
• Mentored some juniors developers and led technical workshops on microservices best practices

Tech Stack: Java 8/11, Spring Boot, Angular, Oracle DB, COBOL integration, Docker, Jenkins

Dec 2020 - May 2021

Enterprise HR Management Platform

• Architected authentication and authorization system using Spring Security and Keycloak, supporting SSO for 5000+ enterprise users
• Designed RESTful APIs for employee skill mapping, search, and classification using Elasticsearch for full-text search capabilities
• Implemented LDAP/Active Directory integration for seamless user provisioning and role management
• Built data models and database schema for complex hierarchical organization structures
• Developed batch processing jobs for daily synchronization with external HR systems

Tech Stack: Java 8, Spring Boot, Spring Security, Keycloak, PostgreSQL, Elasticsearch, LDAP

Feb 2020 - Dec 2020

Social Networking Mobile Application

• Led complete backend migration from JHipster monolith to Quarkus microservices, improving startup time and reducing memory footprint
• Implemented real-time messaging features using WebSockets and server-sent events
• Designed location-based matching algorithm for social event recommendations
• Built push notification service integrating with Firebase Cloud Messaging
• Containerized applications using Docker and implemented local development environment with docker-compose

Tech Stack: Java, Quarkus, Keycloak, PostgreSQL, Docker, Firebase, WebSockets

Oct 2018 - Dec 2019

Telecom Services Platform for Orange

• Developed REST APIs for TV service provisioning and content delivery management
• Implemented distributed caching layer using Hazelcast, improving API response times
• Built JMX-based monitoring for cache performance and system health metrics
• Wrote comprehensive technical specifications and API documentation

Tech Stack: Java, Spring Boot, Hazelcast, JMX, Docker, JUnit, Mockito

• Developing multiplayer game backend using C# and GDScript
• Implementing real-time synchronization and state management

• Built TypeScript ETL pipeline processing 500K+ accident records
• Developed interactive data visualization dashboard with Chart.js

• Building high-performance REST APIs with Go and Gin framework