Sergio Andres Köller Vargas
Verified Expert in Engineering
Software Developer
Sergio is a developer with an entrepreneurial soul who's passionate about creating amazing, new products while building strong working relationships with his colleagues. For the last five years, Sergio has been working as a full-stack developer in Bolivia, the United States, and Europe.
Portfolio
Experience
Availability
Preferred Environment
Google, GitLab, Slack, Ubuntu
The most amazing...
...project I've worked on is a blockchain-based voting system that was considered for the electoral process of Bolivian state companies.
Work Experience
Senior Full-stack Developer
Finsera
- Developed and deployed a web application for a quant trading system using React, Material UI, and Fast API.
- Managed a small team as a technical lead, ensuring timely completion of all web-related tasks and projects.
- Designed and architected the web application's front-end infrastructure in collaboration with the CTO, resulting in a scalable and robust solution.
Senior Full-stack Developer
Truextend
- Developed a full-stack (internal) system for tracking the weekly progress of team members and teams.
- Designed and implemented an architecture for Ruby on Rails APIs abstracting the controller logic into commands (based on the command-driven architecture).
- Built an API for abstracting the payments of different gateways (Stripe, Dwolla, etc).
- Implemented Ruby on Rails API wrappers for Oracle database stored procedures.
- Updated legacy Rails projects to work on Rails 5 and Ruby 2.3.
Senior Full-stack Developer
Creator Mobile
- Developed an app to help apartment buyers monitor the construction of their new apartments, managing payment plans, and accommodation.
- Built a web-and-mobile-based app for a Bolivian social network centered around family life; this includes connecting with nursing homes, schools, and daycares. This system is being launched in Cochabamba, Bolivia.
- Implemented the back end (using cloud functions) for a hotel management system.
- Developed an app for the Scusa restaurant in Santa Cruz, Bolivia. The app reflects the restaurant's experience of homemade dinners.
Senior Full-stack Developer
Freelance Work
- Implemented a web app (full-stack) for peer-review that is being used in some classes in ETH Zurich, MIT, and others.
- Developed a set of apps for food orders, deliveries, and restaurant management for a food delivery project.
- Built an MVP for automatic cryptocurrencies trading using the binance API and technical analysis.
- Maintained more than 20 web-based systems in Digital Ocean servers.
- Automated the recollection of more than 10,000 job offers in Mexico DF for future data analysis.
- Developed informational websites for more than ten businesses in Bolivia.
- Implemented a system to track the traffic in and out of stores. This involved implementing the sensors, NodemMCU, back end, and a web app. This system is used in more than 50 stores around Bolivia.
Experience
Voting System Based on Blockchain Technology
http://www.scielo.org.bo/scielo.php?script=sci_abstract&pid=S1683-07892019000200006&lng=es&nrm=iso&tlng=enTechnologies: Multichain, Ruby on Rails, PostgreSQL
DVSN: Peer-review System
http://dvsn.app/Technologies: Ruby on Rails, PostgreSQL, Bootstrap
Scusa App
Technologies: React Native
TRIII | Efficient Family Apartments
https://play.google.com/store/apps/details?id=com.creatormobile.triii&hl=en_USTechnologies: React Native, Firebase
Informational Website for the Architect Raul Maclean
Technologies: Laravel, PostreSQL, Boostrap
Cryptocurrency Trader
Technologies: Laravel, Binance API
Skills
Libraries/APIs
React, React Redux, Scikit-learn, Pandas, TensorFlow
Languages
Ruby, JavaScript, C++, Python 3
Frameworks
React Native, Material UI, Laravel, Ruby on Rails (RoR), Laravel 5
Platforms
Ubuntu, Firebase, DigitalOcean, Linux, Oracle Database, MultiChain, Blockchain
Other
Web MVC, Web Development, Google, Optimization Algorithms
Tools
GitLab, NGINX, Apache, Watir, Git, Slack, RSpec
Paradigms
REST, Agile, Test-driven Development (TDD)
Storage
JSON, PostgreSQL
Education
Master's Degree in Artificial Intelligence
International University of Valencia - Valencia, Spain
Bachelor's Degree in Systems Engineering
Universidad Católica Boliviana "San Pablo" - La Paz, Bolivia
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