# Gastón User Gastón User is a remote worker on Himalayas, Staff Engineer, Order Domain at Redcare Pharmacy (Shop Apotheke Europe), based in Germany. Source: https://himalayas.app/@gnchark ```text Staff Backend Engineer, former university professor ``` | Detail | Value | | --- | --- | | Availability | Open to opportunities | | Location | Germany | | Authorized to work in | Germany | | Salary expectations | 105k+ EUR | | Job categories | Backend Engineer, Software Development Lead, Software Design Engineer | | Skills | Backend Engineering, Software Architecture, Domain Driven Design, Event Storming, Microservices, Event Driven Architecture, System Design, REST API Design, Monolith Decomposition, Strangler Fig Migration, Transactional Outboxes, Dead Letter Queues, Java, Kotlin, Spring Boot | | LinkedIn | https://linkedin.com/in/gastoncharkiewicz | ## About ```text At Redcare Pharmacy, I built the Order domain team from zero and ran an Event Storming across five teams, mapping the end-to-end order flow and establishing domain boundaries they agreed on. I provided guidance in the design and delivery of Async Order Creation, which finalises orders on payment authorisation, and root-caused a defect costing about 350 orders a day. I coordinated the fix across four domains and added KPIs and observability to surface similar failures. At FreeNow, I owned rider incentives end to end and designed geo-located campaign services used across all nine markets. I also improved their ability to handle load. At JP Morgan Chase, I designed a relationship-based prospecting platform for Wealth Management, consolidating datasets into a Neo4j graph. Earlier, I taught computer science at Universidad Nacional de Quilmes for six years. ``` ## Experience ### Staff Engineer, Order Domain (current) Redcare Pharmacy (Shop Apotheke Europe). Apr 2025 - Present ```text Built the Order domain team from zero, ran a month-long DDD Event Storming across five teams, and defined the team's architecture North Star and product KPIs. Guided the design and delivery of Async Order Creation and root-caused a silent order-cancellation defect costing ~350 orders a day. ``` Skills: Java, Spring-Boot, RabbitMQ, MongoDB, MySQL, Docker, Kubernetes, GCP, Grafana, Claude-Code, Domain-Driven-Design, Event-Storming, Strangler-Fig, ADR, Observability ### Lead Backend Engineer, Rider Incentives [FreeNow](https://himalayas.app/companies/free-now). Oct 2022 - Jun 2024 ```text Owned rider incentives end to end, designed and led development of geo-located campaign services running in all nine markets, and introduced the team's working agreements and knowledge-transfer sessions. ``` Skills: Java, Kotlin, Spring-Boot, MongoDB, MariaDB, Docker, AWS, Datadog, Caching, Circuit-Breakers, Rate-limiting, API-Design ### Software Development Lead, Area X [JP Morgan Chase](https://himalayas.app/companies/jpmorgan-chase-co). Sep 2020 - Feb 2022 ```text Tech lead for a seven-engineer team shipping cross-line-of-business MVPs. Designed and led a relationship-based prospecting platform for Wealth Management using Neo4j, and delivered an ML-based web scraper. ``` Skills: Java, Spring-Framework, Hibernate, Python, React, Neo4j, MySQL, MariaDB, Kubernetes, Cloud-Foundry, Machine-Learning, Web-Scraping ### Senior Software Developer, Markets Technology (FX) [JP Morgan Chase](https://himalayas.app/companies/jpmorgan-chase-co). Nov 2018 - Sep 2020 ```text Redesigned FX portfolio risk monitoring into two tiers: event-driven Python monitors for fast alerts and after-hours monitors for heavier evaluations. Built a self-service UI for Middle Office users to tune alert thresholds and set up monitors. ``` Skills: Python, Event-Driven-Architecture, UI-Development, Risk-Monitoring, Self-Service-Tools-Development ### Senior Software Developer, Markets Execution [JP Morgan Chase](https://himalayas.app/companies/jpmorgan-chase-co). Sep 2017 - Oct 2018 ```text Designed mobile server features for Execute, JP Morgan's institutional trading platform, led third-party system integrations, and contributed to its infrastructure redesign. ``` Skills: Java, Spring-Framework, Hibernate, Python, React, Neo4j, MySQL, MariaDB, Kubernetes, Cloud-Foundry ### Professor and Teaching Assistant Universidad Nacional de Quilmes. Mar 2012 - Oct 2018 ```text Taught six years of computer science courses including Advanced Persistence Strategies, Introduction to Database Systems, Object-Oriented Programming I, and Operating Systems. Co-directed a thesis and published research. ``` Skills: Teaching, Computer-Science, DataBase-Systems, Object-Oriented-Programming, Operating-System, Research ### Software Design Engineer Clarius Consulting. Oct 2014 - Jun 2017 ```text Consulted for Microsoft, Atmel, Nissan, and Honeywell on Visual Studio extensibility, IoT platforms development, and cloud architecture. Owned design and architecture review on client engagements and mentored teammates. ``` Skills: Visual-Studio-Extensibility, IoT, Cloud-Architecture, Azure, Design-Reviews, Mentorship ### Awareness & Research Specialist [ESET Latin America](https://himalayas.app/companies/eset-nederland). Dec 2013 - Jun 2014 ```text Conducted security research and malware analysis, designed a botnet tracking system, and implemented two-factor authentication for a banking application. Served as company spokesperson at information security conferences. ``` Skills: Security-Research, Malware-Analysis, Botnet-Attack-Detection, 2-Factor-Authentication, Public-Speaking ## Education ### Universidad Nacional de Quilmes Software Development Degree, Software Development. 2013 - 2014 ```text Software Development Degree from Universidad Nacional de Quilmes, completed in 2014. ``` ### Universidad Nacional de Quilmes Computer Programming Degree, Computer Programming. 2008 - 2013 ```text Computer Programming Degree from Universidad Nacional de Quilmes, completed in 2013. ``` ## Tech stack - Kubernetes - Jenkins - CircleCI - GitHub Actions - GitLab CI - MySQL - PostgreSQL - MongoDB - MariaDB - Spring Boot - Spring - Neo4j - Redis - Terraform - React - Python - Java - C# - Kotlin - RabbitMQ - Grafana - SQLAlchemy - Hibernate - Datadog - Cloud Foundry - JUnit - Docker - SQL - Testcontainers - Claude Code - AWS - Azure To contact Gastón, message them from this profile with a Himalayas employer account: [Hire on Himalayas](https://himalayas.app/hire). ## People also viewed - [josv me](https://himalayas.app/@josvme): Software Architecture Expert, Kaufland E Commerce GmbH - [luis enrique torres zambrano](https://himalayas.app/@luisenriquetorreszam): IT Instructor, CJAVA - [Stefan Zgondea](https://himalayas.app/@stefanzgondea): Backend Engineer, Mercedes MeStore - [Emilio Arenas](https://himalayas.app/@emarbo): Chief Technological Officer, AndroNautic - [Jaroslaw Groscyk](https://himalayas.app/@jaroslawgroscyk): Technical Consultant, FourEnergy GmbH - [Alex Conti](https://himalayas.app/@alexconti): Staff Backend Engineer, Enmacc GmbH - [Vishwas User](https://himalayas.app/@vishwasuser1): Senior Java Engineer, Airbus - [baba enter](https://himalayas.app/@babaenter): Lead Software Engineer, AlgoMinds GmbH - [Mofaggol Hoshen](https://himalayas.app/@mofaggolhoshen): Senior Software Developer, Quipu GmbH - [Nwosu Happiness](https://himalayas.app/@nwosuhappiness): Senior Software Engineer, Zalando