Vadim Ovcearenco, Developer in Central Athens, Greece
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Vadim Ovcearenco

Verified Expert  in Engineering

Software Engineering Developer

Location
Central Athens, Greece
Toptal Member Since
August 22, 2016

Vadim is an accomplished senior software engineer with over 20 years of experience. Vadim has a solid technical background and extensive expertise in both front- and back-end web development, interactive web applications, and more, enabling him to deliver exceptional results across various projects.

Portfolio

Toptal
Amazon Web Services (AWS), REST, Docker, DB, Linux, Flask, Django, Python...
Kiwi
Python, Celery, Google Cloud Platform (GCP), Amazon Web Services (AWS), Flask...
The Signal Group
JavaScript, R, RStudio Shiny, Azure, Python, Linux, Flask, OAuth 2, Poetry...

Experience

Availability

Part-time

Preferred Environment

Git, Vim Text Editor, Linux

The most amazing...

...project I've contributed to involved stream image collecting, processing, and analysis on the AWS and Google platforms using Docker and auto-scaling.

Work Experience

Software Developer

2016 - PRESENT
Toptal
  • Contributed to the development of Hollywood Live, a massively multiplayer mobile project that involved many different disciplines like ultra-low latency live streaming video, Elixir web sockets, and a Django back-end for CRUD tasks and web view.
  • Helped build Cobalt Archive, an email/web archive application. The client can archive his/her emails and websites using the web app.
  • Worked on Quantified Skin, an app that collects, processes, and analyzes skin photos using AI.
  • Helped create the Vroom ADF workflow, which allows the user to create ADF documents based on incoming emails. It provides robust error handling.
Technologies: Amazon Web Services (AWS), REST, Docker, DB, Linux, Flask, Django, Python, FastAPI, SQLAlchemy, Pydantic, Poetry, SDKs, APIs, API Integration, REST APIs, Django REST Framework, OAuth, Back-end, Test-driven Development (TDD), Web Development, AWS SDK

Senior Software Engeneer

2022 - 2024
Kiwi
  • Fixed Celery implementation and avoided task duplication. As a result, the team could set up a monitoring tool and significantly decrease the number of errors.
  • Added 3D Secure (payment verification) steps to the existing payment workflow.
  • Designed and implemented a test environment to test different payment workflows.
  • Integrated fraud and risk verification in the payment process.
Technologies: Python, Celery, Google Cloud Platform (GCP), Amazon Web Services (AWS), Flask, FastAPI, SQLAlchemy, PostgreSQL, Datadog, Pydantic, Poetry, OAuth 2, SDKs, APIs, API Integration, REST APIs, Docker, Kubernetes, OAuth, Back-end, Test-driven Development (TDD), Web Development, Lambda Functions

Senior Full-stack Developer

2021 - 2023
The Signal Group
  • Created a pipeline to fetch data from the clients, process them, and insert them into the internal database.
  • Visualized data using Shiny (R language) framework.
  • Created a custom authentication plugin for the Shiny framework and deployed the Shiny application on the Azure server.
Technologies: JavaScript, R, RStudio Shiny, Azure, Python, Linux, Flask, OAuth 2, Poetry, SDKs, APIs, API Integration, REST APIs, Docker, OAuth, Back-end, Test-driven Development (TDD), Web Development

Senior Full-stack Developer

2020 - 2021
MoRo Technology Srl
  • Integrated HERE WeGo API into the application (back end and front end).
  • Created an edit tool for maps to allow a user to add points of interest, paths, and other shapes.
  • Built a prediction model for exited data and visualized it on the front end.
Technologies: JavaScript, TypeScript, Node.js, React, Python, Flask, HERE Maps API, FastAPI, Poetry, OAuth 2, SDKs, APIs, API Integration, REST APIs, Docker, OAuth, Back-end, Test-driven Development (TDD), Web Development, AWS SDK, Lambda Functions

Senior Software Engineer, Team Leader

2013 - 2016
Rebelmouse
  • Developed back-end features using Python as the main language. Analyzed requirements, designed architecture, and led the team. Did DSL development, from parsing and compilation to processing.
  • Supported the back-end of a CMS, including a custom template language, based on XML syntax, tightly integrated with the data access layer. Extremely extendable on any level (custom tags, custom handers for existed tags, dynamic module loading, custom data models, and custom data access layer).
  • Built an image upload tool, using AWS, a REST API on Python, resizing, and a crop tool written in JavaScript (Backbone).
  • Developed a central authentication service. As each customer can have several web portals and plays different roles on them, we needed a central authentication service to provide this functionality.
Technologies: Redis, MongoDB, MySQL, Django, Python, SQLAlchemy, SDKs, APIs, API Integration, REST APIs, OAuth, Back-end, Test-driven Development (TDD), Web Development, AWS SDK

Senior Software Engineer

2012 - 2013
OelandOnline
  • Analyzed, designed, developed, and supported the company’s web site in addition to managing projects and creating documentation.
  • Built a datagrid widget.
  • Created reports.
Technologies: PostgreSQL, Django, Python, Back-end

Senior Software Engineer

2011 - 2012
oDeskCore
  • Developed and maintained large applications (such as managerial tools for maintenance and control of social networks content) following TDD and Agile development.
  • Built an operator time tracking system for Facebook.
  • Implemented an efficient algorithm to search for bad words in the user's posts, operating up to 10 times faster than a Regex search.
  • Created Chrome plugins.
Technologies: Git, Flask, Django, Python, Linux, Back-end

Senior Developer

2003 - 2011
Cosmorama
  • Moved the product, originally written on classic ASP, to .NET. We used XML+XSLT rendering, which allows us to change the .NET version without deep refactoring.
  • Employed Backbone.js and AngularJS as a front-end framework.
  • Implemented localization in the XML+XSLT transformation.
Technologies: JavaScript

Lead Software Engineer

2001 - 2011
Greek Travel Pages
  • Created and supported a tourist portal and document workflow application.
  • Built a web portal.
  • Created reports using XML + XSLT.
  • Developed and maintained an MS SQL database.
Technologies: SQL

Senior Software Analyst and Consultant

2005 - 2006
Actiglobe
  • Created and supported an online air ticket reservation system using Galileo.
Technologies: Microsoft SQL Server

Hollywood Live - Quiz Online Game

Massive multiplayer mobile project that involved many different disciplines like ultra low latency live streaming video, Elixir web sockets and a Django back-end for CRUD tasks and web views.

Role:
System Admin, DB Admin, Web Admin, Back-end Python and Elixir Developer

Technologies:
AWS, NGINX, MySQL, Python, Django, JavaScript, Elixir, Phoenix

Challenges:
We used Elixir/Phoenix to create web socket channels with clients. It gave us best performance and almost no latency.

Primesyft - Contract Management App

Prymesyft is software house specialized in web applications. They needed the app to control contracts, payments, project progress and tasks management for the client.

Role:
Full-stack Developer

Technologies:
AWS, EC2, RDS, Python, Flask, SqlAlchemy, AngularJS

Challenges:
Find the best AngularJS architecture to provide easy development and updates.

JDM Wealth Management - Cobalt Archive

Description:
The application to archive email/web data of a client. A client can create account on the web app and set up what site and what mails he/she wants to archive.

Role:
Full-stack Developer. I was responsible for email archiving.
All incoming emails should be parsed, inserted in DB and search engine (Elasticsearch).

Technologies:
Python, Django, Docker, Amazon SQS, Amazon SNS, Vue.js, Postgres, Elasticsearch

Challenges:
Create a robust workflow for email processing. User permission access, Effective archive search and management.

Quantified Skin - Skin Analyzer on AWS

Description:
Collecting, processing and analyzing skin photos using AWS. The company previously had the project running on GCP.

Role:
As most of the code was written for GCP (by me), I had to migrate to AWS using AWS tools.

Technologies:
EC2, Elastic Beanstalk, Elastic Container Service, Lambda, Auto Scaling, Docker, S3, RDS, SQS, SNS, CloudWatch. CodeCommit, Flask, Ubuntu, JavaScript

Challenges:
Find the best tools in AWS to optimize performance vs. cost. Improve the error handling flow.

Quantified Skin - Skin Analyzer on GCP

Description:
Collecting, processing and analyzing skin photos using Google Cloud Platform (GCP)

Role:
I had to design software and hardware architecture to create an API REST interface for the mobile client, to create a minimum-functionality web client using JavaScript libs.
The system should be able to process 6000 photos per hour.

Technologies:
BigQuery, Storage, Datastore, Kubernetes, Google Logging, Compute Engine, Queues, Flask, Ubuntu, JavaScript

Challenges:
To provide required performance, we used Google Container Auto-scaling. All errors are saved in a special queue for processing manually later. The analyzer was run every day and computed all statistical data.

Ivysaur - Flask

https://github.com/perses76/portfolio/tree/master/ivysaur
Q&A education application.

Flask, PostgreSQL, SQLAlchemy

Vroom - Log Analyzer - AWS, Python

https://github.com/perses76/portfolio/tree/master/vroom-log-analyzer
Copy log from AWS to Google Cloud and filter it.

Google App Engine, Google Storage, Python, AWS, S3

Vroom Doc Flow - Google Cloud

https://github.com/perses76/portfolio/tree/master/vroom-adf-workflow
Organize ADF workflow.

Google App Engine, Google Pub Sub, Google Big Data, Python

Kiwi.com - Airline Ticket Booking

http://www.kiwi.com
Kiwi.com is a web platform for airline ticket booking. I worked as a back-end developer and was a member of the fintech department.

As a senior software engineer, I implemented the payment module using card payments, Apple payments, and others. The main focus was on system reliability and error handling. My team used an advanced monitoring tool (Datadog) and reports to track all payments.
1993 - 1998

Master's Degree in Design and Manufacturing of Electronic Devices

Technical University of Moldova - Chichinev

MAY 2011 - MAY 2012

Microsoft Certified Database Administrator (MSDBA) on Microsoft SQL Server

Microsoft

OCTOBER 2003 - DECEMBER 2012

Microsoft Certified Application Developer (MCSD) for Microsoft.NET

Microsoft

Libraries/APIs

React, Pydantic, REST APIs, Vue, SQLAlchemy, Node.js, HERE Maps API

Tools

Celery, AWS SDK, Cron, Vim Text Editor, Git, Amazon Elastic Container Registry (ECR)

Frameworks

Flask, Django, Django REST Framework, RStudio Shiny, OAuth 2

Languages

SQL, Python, JavaScript, Elixir, TypeScript, R

Paradigms

Object-oriented Programming (OOP), Test-driven Development (TDD), Agile Software Development, REST, Data Science

Platforms

Docker, Amazon Web Services (AWS), Linux, Google Cloud Platform (GCP), Amazon EC2, Azure, Kubernetes, Debian, AWS Lambda

Storage

PostgreSQL, MongoDB, NoSQL, MySQL, Redis, Redshift, Microsoft SQL Server, DB, Databases, Datadog

Other

Software Engineering, Data Modeling, APIs, API Integration, FastAPI, Back-end, Web Development, Data Engineering, Poetry, SDKs, OAuth, Lambda Functions, Data Analysis

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