Pavlo Mashchak, Developer in Orlando, FL, United States
Pavlo is currently unavailable

Pavlo Mashchak

Software Engineer and Developer

Orlando, FL, United States

Toptal member since October 14, 2025

Expertise
Software DevelopmentBack-end DevelopersFull-stackDashboardRuby on RailsRubyJavaScriptCSSHTML5Front EndPostgreSQLAutomationREST APIReact.js
Bio

Pavlo is a full-stack software engineer with 15+ years of experience building scalable web applications in Ruby on Rails. Skilled in Ruby, JavaScript, TypeScript, React, and Node.js, he works with SQL and NoSQL databases, including PostgreSQL, MySQL, MongoDB, and Elasticsearch. His DevOps expertise spans AWS, Docker, Ansible, and CI/CD. Pavlo delivers clean, maintainable APIs and microservices focused on performance and automation.

Portfolio

We Are MRKTNG Inc
Python, JavaScript, CSS, HTML5, React, Node.js, Back-end Development...
Atkins & Pearce
Ruby on Rails 6, Ruby on Rails API, JavaScript, React, PostgreSQL, Heroku...
WebIntegrated LLC
Ruby on Rails 6, Hotwire, Vanilla JS, Tailwind CSS, MySQL, REST, Front-end...

Experience

  • Ruby on Rails 8 - 15 years
  • PostgreSQL - 10 years
  • Sidekiq - 10 years
  • React - 8 years
  • MongoDB - 5 years
  • Docker - 4 years
  • Python - 3 years
  • Node.js - 2 years

Preferred Environment

Python, React, PostgreSQL, MongoDB, Elastic, Ruby, Ruby on Rails (RoR), TypeScript, Supabase, AI Agents

The most amazing...

...work I've done is building a number of applications and services related to CRM and document processing, including complex server compositions.

Work Experience

Full-stack Python/Node.js/React Developer

2025 - 2025
We Are MRKTNG Inc
  • Designed and implemented a FastAPI-based analytics back end processing trading data, exposing async APIs for charts, and reporting pages.
  • Built data aggregation pipelines in MongoDB to compute prices, volumes, and aggregation metrics. Reduced client-side processing.
  • Created full Dockerized setup, and staging Linux setup instance, using Ubuntu, Nginx, scripting, setup MongoDB services ensuring automatic system restart and failover.
  • Developed a React reporting UI with dynamic charts and tables.
Technologies: Python, JavaScript, CSS, HTML5, React, Node.js, Back-end Development, Data Pipelines

Senior Software Engineer

2022 - 2025
Atkins & Pearce
  • Reduced background jobs processing time by optimizing SQL queries, 3rd-party API calls.
  • Decreased release cycle by switching to GitFlow, rebuilt the CI/CD pipelines, and implemented SQL schema management.
  • Built the CI/CD pipeline with GitHub and Docker. Integrated DataDog agents across the entire infrastructure.
  • Architected multi-service applications with the Ruby on Rails stack.
Technologies: Ruby on Rails 6, Ruby on Rails API, JavaScript, React, PostgreSQL, Heroku, Redis, Microsoft SQL Server, Datadog, Observability Tools, Ansible, Docker, Apache Kafka, Ruby on Rails (RoR), Amazon Web Services (AWS), REST, Front-end, Back-end, TypeScript, Dashboards, CI/CD Pipelines, Front-end Development, REST APIs, Real-time Data, Full-stack Development, Node.js, CSS, HTML5, ETL, Back-end Development, Data Pipelines, Python

Senior Software Engineer

2022 - 2022
WebIntegrated LLC
  • Built Ruby on Rails website to manage churches and mission members (https://converge.org/).
  • Decreased page load speed by integration of Rails Hotwire for UI components.
  • Created data structures and models for members table schema.
Technologies: Ruby on Rails 6, Hotwire, Vanilla JS, Tailwind CSS, MySQL, REST, Front-end, Back-end, Dashboards, CI/CD Pipelines, Front-end Development, REST APIs, Full-stack Development, CSS, HTML5

Senior Software Engineer

2021 - 2022
Nucleus Healthcare
  • Reworked the Ruby back end for the COVID-19 testing platform to support multi-tenancy. Changed authorization and lab results data handling isolation per tenant organization.
  • Refactored test scopes to use more flexible libraries like Shoulda, Factories for test suite data sampling bootstrapping.
  • Migrated UI modules from legacy jQuery JavaScript framework to React components.
Technologies: JavaScript, React, Ruby on Rails 6, PostgreSQL, RSpec, Sidekiq, Docker, SQL, Ruby on Rails 5, Amazon Web Services (AWS), REST, ActiveAdmin, Front-end, Back-end, TypeScript, Dashboards, Application State Management, CI/CD Pipelines, Front-end Development, REST APIs, API Integration, Full-stack Development, CSS, HTML5

Senior Ruby on Rails Developer

2021 - 2021
Agari Data Inc
  • Built dashboards for vulnerability reports based on SPF, DKIM, and DMARC analysis.
  • Extracted portion of email corrections into Python microservices infrastructure.
  • Refactored UI logic with Ember views conversion to React.
Technologies: Ruby on Rails 6, Python, FastAPI, Ember.js, PostgreSQL, Docker, Enterprise Cybersecurity, Cybersecurity Automation, DomainKeys Identified Mail (DKIM), DMARC, SPF, Phishing Simulation & Analysis, Ruby on Rails 5, REST, Front-end, Back-end, Dashboards, CI/CD Pipelines, Front-end Development, GraphQL API, REST APIs, Full-stack Development, CSS, HTML5

Senior Software Engineer

2018 - 2021
Forte Group
  • Worked as a consultant for Fortune's top 500 companies in legal software, healthcare, drug development, patient portals, clinical trials, and the sports club memberships industries.
  • Created a sequential Ruby handler to process legal document assemblies. Integrated React and Redux components.
  • Redesigned plain PHP SQL queries to use the PHP Data Objects (PDO) module.
Technologies: Ruby on Rails 6, PHP, jQuery, Bootstrap, React, RSpec, APIs, MySQL, Git, Docker, Ansible, JavaScript, Amazon Web Services (AWS), Front-end, GraphQL, Back-end, Dashboards, CI/CD Pipelines, Front-end Development, GraphQL API, REST APIs, CSS, HTML5

Senior Software Engineer

2016 - 2018
Apptopia
  • Created ETL scrapers to parse mobile applications metadata.
  • Built Ruby scripts to transfer and manipulate data into the Cassandra Data Lake.
  • Migrated and refactored page architecture with Backbone Slim views into React components.
Technologies: Ruby on Rails 4, Ruby Gems, Ruby on Rails 6, JavaScript, Cassandra, Git, ETL, React, Backbone.js, Bootstrap, AWS IoT, Python, REST, ActiveAdmin, Chart.js, Dashboards, Front-end Development, Artificial Intelligence (AI)

Senior Ruby on Rails Developer

2014 - 2016
Forte Group
  • Provided software development consulting services for Fortune 500 companies like Comcast, Xfinity, and AT&T.
  • Created authentication Oauth service for AT&T internal store provisioning system.
  • Refactored Java callbacks for set top box UI for Comcast – Home Security.
  • Designed Ruby API game authentication server for Xfinity Games project.
Technologies: Ruby on Rails 4, APIs, Backbone.js, jQuery, Splunk, Java, Java SE (Core Java), Jenkins, Git, Selenium, MySQL, Apache ServiceMix, REST, Front-end Development

Senior Ruby on Rails Developer

2011 - 2012
Helios Technologies
  • Developed multiple SaaS startup projects with rapid prototyping and full-cycle development.
  • Built product architecture, video conversion module for Ant.com, video and indexing platform.
  • Implemented OAuth2 modules and JavaScript SDK for ID.net, authentication and identity platform. Fintech module for secure bank transaction API.
Technologies: Ruby on Rails 4, JavaScript, Backbone.js, MySQL, MongoDB, Elasticsearch, Git, Linux, REST, ActiveAdmin

Ruby on Rails Developer

2010 - 2011
GlobalLogic
  • Created an ETL pipeline to move the MySQL database table-by-table data into a new database schema.
  • Migrated educational platform from Ruby on Rails 1.2 to version 3.0.
  • Created SQL data transition scripts to migrate cross-database data.
Technologies: Ruby on Rails 2, APIs, MySQL, RSpec, Redis, Memcached, Linux, Apache, NGINX, REST

Experience

Manufacturing Application

https://www.atkinsandpearce.com/
A scheduling system to monitor machinery load for shifts. This project included complex data calculations and integration with 3rd-party services. The application was built using the Ruby on Rails stack, with React as the UI library, and PostgreSQL and Microsoft SQL Server as the database engines.

Authentication & Identity Platform

https://www.id.net/
ID.net, an authentication and identity platform. A unified identity management platform providing OAuth2-based authentication, single sign-on, and API integrations for third-party web applications, including secure fintech and banking connectivity.

Ant.com – Video Conversion & Indexing Platform

https://www.ant.com/
A web platform for discovering, downloading, and converting online videos, featuring a Ruby-based media processing pipeline, CLI automation, and Elasticsearch-powered content indexing. Includes several JavaScript plugins and back-end video converters.

Education

1999 - 2005

Master's Degree in Computer Systems and Networks

Lviv Polytechnic National University - Lviv, Ukraine

Certifications

NOVEMBER 2025 - PRESENT

Python: SOLID Principles and Top Design Patterns

Udemy

NOVEMBER 2025 - PRESENT

MCP Fundamentals for Building AI Agents

Educative

SEPTEMBER 2025 - PRESENT

The Complete Python Developer

Udemy

Skills

Libraries/APIs

Sidekiq, Ruby on Rails API, React, GraphQL API, REST APIs, Node.js, jQuery, Backbone.js, Chart.js

Tools

RSpec, Observability Tools, Elastic, Ansible, Git, Splunk, Jenkins, Hotwire, Apache, NGINX

Languages

JavaScript, Ruby, CSS, HTML5, Python, TypeScript, Elixir, SQL, PHP, Java, Java SE (Core Java), GraphQL

Frameworks

Ruby on Rails 6, Ruby on Rails (RoR), Ruby on Rails 5, Ember.js, SPF, Bootstrap, Ruby on Rails 4, Selenium, Vanilla JS, Tailwind CSS, Ruby on Rails 2

Paradigms

REST, Automation, ETL, Prototype-based OOP, Model Context Protocol (MCP)

Platforms

Heroku, AWS IoT, Amazon Web Services (AWS), Docker, Apache Kafka, Linux

Storage

PostgreSQL, MySQL, MongoDB, Microsoft SQL Server, Redis, Datadog, Cassandra, Elasticsearch, Memcached, Data Pipelines

Other

Ruby on Rails 8, Software, APIs, Back-end, Dashboards, CI/CD Pipelines, Full-stack Development, ActiveAdmin, Front-end, Application State Management, Front-end Development, Real-time Data, Electronics, FastAPI, Enterprise Cybersecurity, Cybersecurity Automation, DomainKeys Identified Mail (DKIM), DMARC, Phishing Simulation & Analysis, Ruby Gems, Apache ServiceMix, OOP Designs, SDKs, Authentication, Identity Server, Shell Commands, Artificial Intelligence (AI), API Integration, AI Agents, Patterns, SOLID Principles, Supabase, Back-end Development

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