Vadim Ovcearenco, Developer in Central Athens, Greece
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Vadim Ovcearenco

Software Engineering Developer

Central Athens, Greece

Toptal member since August 22, 2016

Bio

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

Mellon Direct Solutions
Python, Amazon Web Services (AWS), Kubernetes, Terraform, Docker, Jenkins...
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

  • Software Engineering - 15 years
  • Python - 14 years
  • Django - 10 years
  • NoSQL - 6 years
  • JavaScript - 5 years
  • Amazon Web Services (AWS) - 5 years
  • React - 3 years
  • Data Science - 2 years

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

Head of IT/Senior Software Engineer

2024 - PRESENT
Mellon Direct Solutions
  • Led the modernization of the company's hybrid infrastructure by introducing AWS, Infrastructure as Code, and CI/CD automation, significantly improving deployment speed and operational reliability.
  • Designed and implemented monitoring and observability solutions using Grafana, Prometheus, and Loki, enabling proactive issue detection across production systems.
  • Automated infrastructure provisioning and application deployments with Jenkins and Ansible, reducing manual operational work and improving deployment consistency.
  • Developed Python automation tools and back-end services supporting business-critical contact center operations running on Windows and Linux platforms.
  • Led a team of five software engineers while remaining hands-on in architecture, back-end development, infrastructure automation, and production support.
  • Improved system availability by implementing standardized deployment processes, centralized logging, and infrastructure automation across multiple environments.
Technologies: Python, Amazon Web Services (AWS), Kubernetes, Terraform, Docker, Jenkins, Ansible, Linux, PostgreSQL, Redis, Grafana, Prometheus, Loki, Git, Workflow, Single Sign-on (SSO), Back-end APIs, AWS Bedrock AgentCore

Senior Python Engineer

2022 - 2024
Kiwi
  • Optimized Celery task execution by eliminating duplicate processing, improving system reliability, and enabling the team to build production monitoring with significantly fewer processing errors.
  • Implemented 3D Secure (3DS) authentication within the payment platform, strengthening payment security while maintaining a seamless customer checkout experience.
  • Designed and implemented a comprehensive testing environment for payment workflows, improving release confidence and reducing regression issues.
  • Integrated fraud detection and risk verification into the payment processing pipeline, increasing transaction security and supporting compliance requirements.
  • Developed back-end services for a high-volume distributed payment platform using Python, Kubernetes, and cloud-native technologies, contributing to reliable and scalable payment processing.
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, GitLab, Containers, GitHub, Redis Cache, PSQL, Relational Databases, On-premise, AWS Lambda, Amazon DynamoDB, DevOps, Amazon Elastic Container Service (ECS), Amazon S3 (AWS S3), Architecture, Full-stack Development, Software Architecture, CI/CD Pipelines, Full-stack, Security, Terraform, Terraform Cloud, Workflow, Single Sign-on (SSO), Back-end APIs

Senior Back-end Engineer (Python)

2021 - 2023
The Signal Group
  • Designed and implemented automated data pipelines that collected, transformed, and loaded client data into internal systems, improving data consistency and reducing manual processing.
  • Developed interactive analytics dashboards using R Shiny, enabling consultants and clients to explore complex datasets through intuitive visualizations.
  • Built a custom authentication plugin for the Shiny platform and deployed the solution to Microsoft Azure, providing secure enterprise access to analytical applications.
  • Developed Python back-end services and automation tools supporting data processing, application integration, and cloud deployment across multiple customer projects.
  • Collaborated with consultants and business stakeholders to transform analytical requirements into scalable data processing and reporting solutions.
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, Containers, GitHub, Redis Cache, Relational Databases, On-premise, TypeScript, DevOps, Amazon S3 (AWS S3), Architecture, Full-stack Development, Software Architecture, CI/CD Pipelines, Full-stack, Security, Amazon Web Services (AWS), Conda, Jupyter Notebook, Workflow, Single Sign-on (SSO), Back-end APIs

Senior Full-stack Developer

2020 - 2021
MoRo Technology Srl
  • Integrated the HERE WeGo Maps platform into a cloud-based application, delivering mapping, routing, and geospatial capabilities across both back-end services and the React front end.
  • Designed and implemented an interactive map editor enabling users to create and manage points of interest, routes, and custom geospatial objects.
  • Developed a machine learning prediction pipeline and integrated its results into the web application, providing real-time visualization of analytical data.
  • Built Python back-end services and REST APIs supporting geospatial processing, secure authentication, and cloud-native deployment on AWS.
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, Containers, GitHub, PSQL, Relational Databases, On-premise, Amazon RDS, Amazon Simple Queue Service (SQS), Amazon S3 (AWS S3), Full-stack Development, Full-stack, Security, Amazon Web Services (AWS), Jupyter Notebook, Workflow, Back-end APIs

Senior Software Engineer, Team Leader

2013 - 2016
Rebelmouse
  • Developed back-end services and core platform features using Python, leading technical implementation from requirements analysis through design, development, and deployment.
  • Extended the CMS back end by implementing a highly customizable XML-based templating engine with dynamic modules, custom tags, and flexible data models.
  • Built an image processing service using Python, AWS, and REST APIs, supporting image uploads, resizing, and client-side editing capabilities.
  • Designed and implemented a centralized authentication service that enabled secure access across multiple customer portals with role-based authorization.
Technologies: Redis, MongoDB, MySQL, Django, Python, SQLAlchemy, SDKs, APIs, API Integration, REST APIs, OAuth, Back-end, Test-driven Development (TDD), Web Development, AWS SDK, GitHub, Redis Cache, Relational Databases, Full-stack Development, Full-stack, Security

Experience

AI-powered Aquarium Design Platform

• Served as the sole back-end developer for an AI-powered aquarium design platform, taking ownership of substantial back-end refactoring and designing the integration with RunPod and ComfyUI for Stable Diffusion image generation. Built a workflow execution pipeline based on JSON graph definitions and integrated it with the Django back end.
• Improved the GPU development infrastructure by moving approximately 5GB of AI models from the Docker deployment path to network storage, reducing environment startup time from 5–7 minutes to approximately 30 seconds. Previously evaluated and configured an AWS EC2-based GPU deployment, including NVIDIA driver setup, before the project moved to RunPod.
• Implemented and maintained Django REST APIs, Auth0 authentication, PostgreSQL integration, and AWS-hosted back-end components while collaborating with the front-end team.

Commercial Real Estate Financial Modeling Platform

I took over an existing commercial real estate financial modeling platform as the primary back-end engineer and brought it to production. I worked directly with the client, independently maintaining and extending the Django application, resolving issues, and adding unit test coverage to improve reliability.

I extended the Excel-based financial modeling functionality using PyWin32 and COM automation, including evaluating alternative approaches to Excel integration against the project's requirements. I built deployment automation for the AWS-hosted application and continued to support and extend the system after taking ownership from the previous developer.

Hollywood Live - High-concurrency Interactive Quiz Platform

Worked as the key back-end developer on an interactive live quiz platform designed for thousands to tens of thousands of concurrent participants. Viewers watched questions broadcast on television and submitted their answers through the web application, requiring a low-latency real-time communication layer.

Designed and developed the Django back end and the real-time WebSocket architecture using Elixir and Phoenix. The Django application handled core application data and management functionality, while Phoenix WebSocket channels supported real-time communication with large numbers of connected clients.

The system was designed and tested for high concurrency, although the product did not ultimately reach production.

JDM Wealth Management - Email Archiving Platform

I developed the email ingestion and archiving subsystem for a wealth management platform used to preserve client communications and web data.

I designed and implemented the workflow for receiving incoming emails through AWS services, processing SNS notifications, retrieving email data from S3, parsing messages and attachments, and persisting the resulting data for archival and downstream processing. I focused on making the ingestion workflow robust and maintainable, including handling different email structures and attachments and integrating the processing pipeline with the existing Django application.

Quantified Skin - Skin Analyzer on AWS

I designed and implemented the AWS infrastructure for a skin image analysis platform that processes photos submitted by participants testing skincare products. The workload had highly concentrated peaks, with approximately 10,000 images arriving in the morning and another 10,000 in the evening, while individual image analysis took approximately one minute.

I also built a containerized processing pipeline using Amazon ECS and S3 around a machine-learning model provided by the data science team. The infrastructure was designed to scale processing capacity during the morning and evening peaks and scale back down as demand subsided, balancing processing throughput with infrastructure cost. I migrated the application from an earlier GCP implementation to AWS and adapted the processing architecture to AWS services.

Education

1993 - 1998

Master's Degree in Design and Manufacturing of Electronic Devices

Technical University of Moldova - Chichinev

Certifications

SEPTEMBER 2024 - SEPTEMBER 2027

AWS Certified Data Engineer – Associate

Amazon Web Services

FEBRUARY 2024 - MARCH 2027

AWS Certified DevOps Engineer – Professional

Amazon Web Services

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

Skills

Libraries/APIs

React, Pydantic, REST APIs, Back-end APIs, SQLAlchemy, Node.js, HERE Maps API

Tools

Celery, AWS SDK, GitHub, Amazon Elastic Container Service (ECS), Cron, GitLab, Amazon Simple Queue Service (SQS), Terraform, Vim Text Editor, Git, Amazon Elastic Container Registry (ECR), AWS Glue, Amazon Athena, Amazon Elastic MapReduce (EMR), AWS CloudFormation, Amazon EKS, Amazon CloudWatch, AWS IAM, Amazon Virtual Private Cloud (VPC), AWS CodeBuild, AWS Systems Manager, Jenkins, Ansible, Grafana, Loki, ComfyUI

Languages

SQL, Python, JavaScript, TypeScript, Elixir, R, C#, HTML, CSS

Frameworks

Flask, Django, Django REST Framework, Next.js, RStudio Shiny, OAuth 2

Paradigms

Object-oriented Programming (OOP), Test-driven Development (TDD), DevOps, Agile Software Development, REST, ETL, Automation

Platforms

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

Storage

PostgreSQL, Redis Cache, Amazon S3 (AWS S3), MongoDB, NoSQL, MySQL, Redis, Redshift, PSQL, Relational Databases, On-premise, Amazon DynamoDB, Microsoft SQL Server, DB, Databases, Datadog, Elasticsearch, Data Pipelines, Data Lakes

Other

Software Engineering, Data Modeling, APIs, API Integration, FastAPI, Back-end, Web Development, Containers, Back-end Development, Architecture, Full-stack Development, Software Architecture, CI/CD Pipelines, Full-stack, Workflow, Data Engineering, Poetry, SDKs, OAuth, Lambda Functions, Amazon RDS, Security, Terraform Cloud, Conda, Artificial Intelligence (AI), Single Sign-on (SSO), AWS Bedrock AgentCore, Data Science, Data Analysis, Software as a Service (SaaS), Amazon Redshift, Infrastructure as Code (IaC), AWS CodePipeline, AWS Monitoring, Prometheus, Stable Diffusion

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