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Denis – Ruby on Rails, React, Node.js, experts in Lemon.io

Denis

From Portugal (GMT+1)

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Full-stack Web DeveloperMiddle
Back-end Web DeveloperSenior
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9 years of commercial experience
AI
Communications
Construction
E-commerce
Edtech
Energy
Healthcare
Job and career services
Logistics
Mental healthcare
Retail
Sports
Telecommunications
Transportation
Platforms
Lemon.io stats
2
projects done
1835
hours worked
2
offers now 🔥

Denis – Ruby on Rails, React, Node.js

Denis is a person with a wide range of experience in IT. Besides commercial experience with Ruby on Rails for the last 5 years, Denis also has practical experience with such demanded technologies as Docker, ElasticSearch, and others. Starting a career in the IT field as the Support Manager made Denis a perfect person to make qualitative and client-oriented products. Denis is an easygoing, kind, and responsible person. Working with him is a pleasure! So, who’s first?

Main technologies
Ruby on Rails
6.5 years
React
1.5 years
Additional skills
Node.js
ElasticSearch
Docker
GraphQL
MySQL
AWS
Bootstrap
Angular
MongoDB
PostgreSQL
Heroku
Tailwind CSS
Redis
Typescript
Apollo GraphQL
Apache Kafka
DynamoDB
AWS Lambda
Nest.js
MariaDB
GCP
PHP
Rewards and achievements
Tech interviewer
Ready to start
ASAP
Direct hire
Potentially possible

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Experience Highlights

Senior Backend Developer
Jan 2024 - Ongoing11 months
Project Overview

User enrolment project. It provides wireless headsets for retail companies so that their teams can communicate. One issue is that, until now, they haven't had a way to assign which user is/was with a specific headset, and that's where this project appeared. It runs on a premise device (built by the company itself), which is basically a Linux machine that communicates with a server on the cloud for reporting purposes. So a basic React application was created where the user could enroll to a headset by typing their username, pin number, and a pairing code. After that, it was registered on a local database and also sent to the cloud.

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Responsibilities:
  • Created on-premise (back end and front end) application architecture;
  • Created most of on-premise Nest.js application;
  • Worked on some features on the front end using React;
  • Wrote code with 70%+ test coverage.
Project Tech stack:
Node.js
Nest.js
MariaDB
Redis
Knex.js
React
MongoDB
MQTT
Senior Backend Developer
May 2023 - Jan 20248 months
Project Overview

It is an international home improvement company with over 2,000 stores, supported by a team of over 78,000 colleagues. Denis worked on the next version of the website's checkout.

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Responsibilities:

Deni`s main area of responsibility was to create new microservices using AWS CDK for infrastructure and store data on DynamoDB. He also used Kafka for communication between services using events.

Project Tech stack:
Node.js
AWS Lambda
AWS CloudFormation
Apache Kafka
DynamoDB
Apollo GraphQL
Typescript
Main developer for the project
Jan 2023 - Nov 20239 months
Project Overview

This project combines medical, behavioral and environmental factors in an insight generating app designed specifically to support Autistic children.

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Responsibilities:
  • Migrated infrastructure from AWS to GCP;
  • Created many new features, including notifications using event drive architecture;
  • Improved many aspects of code, including solving bugs and refactoring bad code;
  • Integrated with the messaging platform.
Project Tech stack:
Ruby on Rails
AWS
GCP
Full-Stack Developer
Apr 2022 - Aug 20224 months
Project Overview

Partbot is an automotive aftermarket dropshipping where users could sell their car parts available to e-commerce merchants, and control how their parts are sold online, and Partbot handles the logistics with its partners.

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Responsibilities:
  • Implemented report an error functionality;
  • Implemented CSV data export;
  • Implemented media section for products (image, videos and etc.)
  • Integrated with Easyship;
  • Integrated with TecAlliance e-commerce.
Project Tech stack:
Ruby on Rails
React
PostgreSQL
Redis
Full-Stack Developer
Jul 2020 - Dec 20211 year 5 months
Project Overview

Transrefrut is a platform that connects football players to clubs or managers. You can share players' experiences, clubs, or managers' openings for players or managers to apply and offer players to be hired.

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Responsibilities:
  • Implemented GraphQL API;
  • Engineered the Requirements;
  • Refactored existing code by applying clean code principles;
  • Created new features end to end (from the Rails Backend to the React Frontend);
  • Created unit test for most of the Backend code;
  • Created Paypal integration.
Project Tech stack:
Ruby on Rails
React
GraphQL
Amazon S3
Full-Stack Ruby on Rails Developer
Jun 2020 - Oct 20211 year 4 months
Project Overview

This was a project created with a partnership between the Federal University of Goiás and the Goiás Government. Students from public education can send their essays on the platform so a machine learning model can review their essays and return their scores from each category. The whole system is made of two parts: a Ruby on Rails application that interacts with the user, stores and sends the essays to another part of the system which uses Python. The second one contains the trained model and is basically a Python FastAPI system.

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Responsibilities:
  • Created the whole ruby on rails system from the ground up;
  • Integrated both systems using REST API requests;
  • Created dashboards for students, teachers, and other education professionals;
  • Dockerized the application.
Project Tech stack:
Ruby on Rails
Docker
MySQL
Full-Stack Ruby on Rails Developer
Dec 2017 - Aug 20191 year 7 months
Project Overview

Olho na Bomba is a project that is created to oversee fuel prices in the state of Goiás in Brazil. It is the platform where the gas station workers insert all fuel prices as they change the value so that customers can see in real-time what those prices are. The price insertion process was law-enforced back then, but it has been revoked, and the whole process is under legal dispute right now.

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Responsibilities:
  • Led the team;
  • Distributed tasks, monitored and reported the results;
  • Created the project architecture;
  • Created the registration, price insertion, and the API for mobile applications;
  • Deployed the application on the government infrastructure.
Project Tech stack:
Ruby on Rails
MongoDB
Full-Stack Ruby on Rails Developer
Apr 2017 - Sep 20181 year 5 months
Project Overview

A platform that connects teachers to students. A student can send essays, receive feedback from the teacher, or sign up for classes.

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Responsibilities:
  • Refactored Code by using clean code principles;
  • Managed system migration from Heroku to AWS;
  • Added new features to the platform;
  • Created a course platform for essay writing boot camps;
  • Mentored intern developers;
  • Improved overall performance using code and database optimization;
  • Provided Quality Assurance support.
Project Tech stack:
Ruby on Rails
MongoDB
Heroku
AWS
Bootstrap

Education

2021
Information Systems
Bachelor

Languages

English
Advanced

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