Mateusz Bielec, Developer in Rzeszow, Poland
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Mateusz Bielec

Verified Expert  in Engineering

Bio

Mateusz is a detail-oriented software developer who specializes in Ruby back ends. He has 10+ years of experience resolving complex domain problems in legacy systems, including fintech, hiring, and recycling industries. Devoted to code review, he advocates for best practices to mitigate business risks and promote a higher-quality codebase. Mateusz has a solid record of improving project maintainability and developer experience in large-scale organizations.

Portfolio

Toptal
Ruby, Ruby on Rails (RoR), PostgreSQL, Sidekiq, GraphQL, REST, RSpec, Agile...
Ironin
Ruby, Ruby on Rails (RoR), PostgreSQL, Elasticsearch, jQuery, Code Review...
PGS Software
Ruby, Heroku, PostgreSQL, Sidekiq, AngularJS, Bootstrap, REST...

Experience

  • Ruby on Rails (RoR) - 14 years
  • Ruby - 14 years
  • Code Review - 13 years
  • Complex Problem Solving - 13 years
  • PostgreSQL - 12 years
  • Agile - 11 years
  • Team Mentoring - 10 years
  • GitHub Actions - 5 years

Availability

Part-time

Preferred Environment

Ruby, Ruby on Rails (RoR), PostgreSQL, GitHub Actions

The most amazing...

...thing I've done is reviving an unmaintained crucial internal application used by hundreds of developers without prior experience in Node.js.

Work Experience

Senior Back-end Engineer

2021 - 2024
Toptal
  • Worked on a Ruby service with 1+ million lines of code and managed 15+ repositories, including internal and open-source gems, tools, and supporting apps. Improved the development experience for hundreds of engineers.
  • Removed the risk of breaking a deployment orchestrator used by 100+ applications by identifying an issue with an outdated Slack integration in Node.js and planning the migration to the up-to-date framework.
  • Participated in a rotational consulting duty to support feature teams using internal libraries and tools. Assisted with debugging and environment setup. Guided daily tasks while maintaining a high SLA for resolved support requests.
  • Improved maintainability of the deployment orchestrator application by upgrading it to the newest Node.js version and introducing a testing layer. This reduced the number of bugs and increased confidence among other developers.
  • Implemented a shared GitHub Action powered by a Ruby script to support gathering comprehensive, technology-agnostic code statistics for 100+ repositories inside the organization.
Technologies: Ruby, Ruby on Rails (RoR), PostgreSQL, Sidekiq, GraphQL, REST, RSpec, Agile, Node.js, TypeScript, Docker, Datadog, GitHub Actions, Code Review, Complex Problem Solving, Team Mentoring

Senior Ruby Developer

2016 - 2021
Ironin
  • Integrated the application with external tax provider services to calculate tax amounts based on the current tax rates and store tax documents for tax compliance purposes.
  • Created a message logger to store custom events and logs on different storages like Elasticsearch via adapter pattern.
  • Implemented an automated mechanism for splitting requested amounts for scheduled payments based on payment type.
Technologies: Ruby, Ruby on Rails (RoR), PostgreSQL, Elasticsearch, jQuery, Code Review, RSpec, Sidekiq, Complex Problem Solving, REST APIs

Software Developer

2013 - 2016
PGS Software
  • Collaborated with the stakeholders daily by gathering the requirements and showcasing key functionalities.
  • Participated in and then led the Ruby ERP app development with a mobile client for nine months. Scaled a data synchronization REST API.
  • Mentored interns and organized internal Ruby workshops.
Technologies: Ruby, Heroku, PostgreSQL, Sidekiq, AngularJS, Bootstrap, REST, Ruby on Rails (RoR), Code Review, RSpec, Complex Problem Solving, Team Mentoring, REST APIs

Software Developer

2011 - 2013
SoftSystem
  • Managed database migrations in Java-based applications.
  • Provided technical support and handled incoming incidents.
  • Diagnosed and resolved a wide range of technical issues.
Technologies: Java, PL/SQL, C#, DevExpress, Enterprise Service Bus (ESB), Code Review

Experience

Outdated Slack Intergration Migration

Removed the risk of breaking a deployment orchestrator used by 100+ applications by identifying an issue with an outdated Slack integration in Node.js and planning the migration to the up-to-date framework. I conducted the initial POC, used the PERT estimation technique, and assessed the risk to prepare the expected delivery date. Also, I collaborated with the main developer on the project, ensuring a seamless migration without any downtime.

Education

2006 - 2011

Master's Degree in Computer Science

Rzeszow University of Technology - Rzeszow, Poland

Skills

Libraries/APIs

Sidekiq, jQuery, REST APIs, Node.js

Tools

RSpec

Languages

Ruby, GraphQL, TypeScript, Java, C#

Frameworks

Ruby on Rails (RoR), Bootstrap, AngularJS

Paradigms

REST, Agile

Platforms

Docker, Heroku

Storage

PostgreSQL, Datadog, Elasticsearch, PL/SQL

Other

Code Review, Team Mentoring, GitHub Actions, Complex Problem Solving, DevExpress, Enterprise Service Bus (ESB), Planning, Estimations, Risk Assessment, Software Development

Collaboration That Works

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