Cezary Tomczyk, Developer in Prague, Czech Republic
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Cezary Tomczyk

Verified Expert  in Engineering

Web App Developer

Prague, Czech Republic
Toptal Member Since
December 7, 2015

Cezary has over ten years of experience in web technologies, and he is passionate about managing projects and people. Cezary has worked the complete product lifecycle from beginning to the end as and is experienced in hand-coding, using the Semantic Web, writing usable code that is cross-browser compliant, and adheres to web content accessibility guidelines from W3C. Cezary specializes in search engine and performance optimization solutions.


Proximity Insight Ltd
JavaScript, Knockout (Knockout.js), Sass
BCLJ Consulting LLC.
JavaScript, HTML5, CSS, Less
eSSENTIAL Accessibility
Website QA, QA Testing, Architecture, APIs, Objectives & Key Results (OKRs)...




Preferred Environment

MacOS, Git, Visual Studio, Web Accessibility

The most amazing...

...project that I've worked on was when I co-authored and deployed the client-side, cross-browser library for Skype for the internet.

Work Experience

JavaScript Developer

2023 - 2023
Proximity Insight Ltd
  • Implemented Font Awesome Pro 6 to use it across different places: inline, CSS, or in Sass.
  • Trained junior engineers and provided feedback on their requests for the code review.
  • Improved UI design based on feedback from the software engineering side. For example, suggestions for states like focus for users who use keyboard navigation.
Technologies: JavaScript, Knockout (Knockout.js), Sass

Front-end UI Developer | Project Maintenance

2020 - 2023
BCLJ Consulting LLC.
  • Normalized front-end workflow to make the whole building consistent.
  • Trained in digital accessibility and provided solutions.
  • Mentored, coached, and helped all team members to walk through the fog of the front-end development.
Technologies: JavaScript, HTML5, CSS, Less

Chief Technology Officer

2019 - 2020
eSSENTIAL Accessibility
  • Interviewed, developed, managed, mentored, and motivated software engineering teams, including QA.
  • Tracked and organized tasks in Jira following the Scrum methodology.
  • Developed and rolled out a scalable, fast, and cross-browser/devices eA platform to manage an automated and manual digital accessibility testing process, including a crawler, analytics, and reports.
  • Created and measured product and team goals (OKRs).
  • Acted as a strong team leader with strategic thinking to execute from, who knows every corner of IT, even hands-on coding.
  • Architected and implemented the development cycle, including Scrum methodology, code review, automated quality steps, CI/CD, deployment, change management, monitoring performance, and executing automated E2E and unit tests.
  • Authored ASLint, an automated accessibility testing tool that is being used in the eA platform.
  • Created/reviewed accessibility rules, processes, and testing strategy as a member of the eA accessibility committee.
Technologies: Website QA, QA Testing, Architecture, APIs, Objectives & Key Results (OKRs), Sass, Scaling, People Management, Management, TypeScript, Accessibility, Web Accessibility, Accessible Rich Internet Applications (ARIA), Front-end Development

Senior Software Engineer

2017 - 2019
  • Created a software development build process, including quality and testing.
  • Mentored team members and achieved 100% higher quality and development velocity.
  • Organized a scrum process successfully and passed the knowledge to others.
Technologies: Scrum Master, Team Mentoring, Mentorship, Agile Software Development, Architecture, Website Performance, Angular, Sass, CSS, HTML5, JavaScript, TypeScript, Accessibility, Web Accessibility, Accessible Rich Internet Applications (ARIA), Front-end Development

Accessibility Engineer

2015 - 2016
  • Responsible for checking quality, giving advice in the accessibility area, and driving accessibility implementations.
Technologies: WCAG 2, HTML5, CSS3, JavaScript, Web Accessibility, Accessible Rich Internet Applications (ARIA), Front-end Development

Software Developer 4 (Principal Engineer)

2015 - 2015
  • Contributed to a project related to the Oracle Applications and Services Cloud that allows users to build the application from independent components and hook REST services.
  • Implemented accessibility standards based on WCAG 2.0 specification.
  • Created a quality, gated check-in validation process. Checked for circular dependencies, linting client-side scripts (JavaScript, Node.js) using the eslint.org tool, and also utilized Sass, HTML, and JSON files.
  • Worked on telemetry to measure the application performance.
  • Aided with the planning, organizing, and monitoring workflow.
Technologies: Model View ViewModel (MVVM), ASP.NET Core MVC, Git, jQuery, Apache Maven, Java, CSS3, HTML5, Sass, JavaScript, Web Accessibility, Accessible Rich Internet Applications (ARIA), Front-end Development

Software Developer 2

2012 - 2015
Microsoft, Skype Division
  • Co-authored the client-side, cross-browser library that provides video, audio, chat, and notifications.
  • Authored the i18n and g11n library; implemented the i18n framework and the right-to-left solutions.
  • Co-led the the team that made Skype for Web more accessible.
  • Created the writing tools for the A/B testing.
  • As a scrum master, managed the process about how the information was exchanged; via various tech session in order to pool shared knowledge.
  • Worked on the build process: the validation and the deployment using Ant and Grunt.
  • Contributed to the construction of the API that connects Office 365 to Skype.
  • Invented a solution that received a patent in the United States.
Technologies: S#arp Architecture, Grunt, Apache Ant, Node.js, C#, CSS3, HTML5, Sass, JavaScript, Front-end Development

Software Developer

2011 - 2011
  • Constructed a dashboard with all the analytics based on data from Nokia Maps.
  • Implemented a responsive design for the dashboard.
  • Authored an extension for Google Chrome that enables one to manage Nokia Maps favorites through the browser directly.
  • Optimized the sorting and presentation of a large amount of data on the dashboard.
  • Created all of the charts using Scalable Vector Graphics (SVG).
  • Developed a library to communicate with Nokia Maps REST services.
Technologies: Elycharts, jQuery, CSS3, HTML5, JavaScript, Front-end Development


2003 - 2011
  • Regulated the finances (budgeting, controlling finance flow, working with accountants), negotiations, and led the web development.
  • Aided in the development of a web-based help desk and CRM applications like tickets, maintaining the FAQ, records, the mailing, Information Technology Infrastructure Library rules, and service/lease agreements. Utilized (X)HTML, CSS, JavaScript, PHP, MySQL, SVN, Git, and XMLHttpRequest.
  • Created a JavaScript framework to manipulate the DOM, events, processing templates, and accessing the data from server.
  • Developed Google Chrome extensions and an application to manage tourist reservations and offers.
  • Performed server administration on the Ubuntu Server; caching the network using Varnish, Apache, MySQL, PostgreSQL, and managing network traffic (balance usage).
Technologies: PHP, CSS3, HTML5, JavaScript


1998 - 2003
Freelance Work
  • Worked on financial documentation and with accountants.
  • Built and maintained strong customer relations for the company; also provided customer support.
  • Provided IT services for small and large companies using ITIL practices; dealt with networks and servers mostly.
  • Created web pages using JavaScript, HTML, and CSS.
Technologies: JavaScript, CSS, HTML, Linux Servers, Windows Server


1997 - 1998
ATS - Systemy Informatyczne Sp. z o.o.
  • Responsible for maintaining customer relations with major customers, generating offers, networking, and aiding in contract negotiations.
Technologies: Customer Service

ASLint | Accessibility Testing Tool

An accessibility testing tool that helps to scan and find accessibility issues on your website content. It covers WCAG 2.1 and best practices. It works from the bookmarklet as well as in CI/CD and works across different browsers. It is fast and reliable.

Company Website

This project was about implementing a WordPress-based website that doesn't have accessibility issues, has high loading performance, and is available on multiple devices. I achieved the goal of zero errors on all website pages and applied a robust quality and deployment process.
1997 - 2001

Bachelor of Science in Computer Systems

Technical University of Computer Science and Information Systems - Szczecin, Poland

1995 - 1997

Partially Completed Bachelor's Degree in Material Engineering

Technical University of Mechanical Engineering - Szczecin, Poland

1990 - 1995

High School Diploma in Mechanical Repair of Rolling Stock (Rail Way Vehicles)

Rails Technical Secondary Schoool - Szczecin, Poland


Node.js, jQuery, RequireJS, JavaScript API for Chrome, WebRTC, React


Grunt, NPM, Adobe Photoshop, Subversion (SVN), Jira, Bower, Git, IntelliJ IDEA, Mocha, Visual Studio, Apache Maven, Apache Ant, Jenkins, VirtualBox, Inkscape, GitHub


Angular, Jasmine, Knockout (Knockout.js), JavaScript MVC, ASP.NET Core MVC, S#arp Architecture, Yii 2, Ember.js


Agile Software Development, Continuous Integration (CI), Object-oriented Programming (OOP), Model View ViewModel (MVVM), Unit Testing, Model View Controller (MVC), Scrum, Test-driven Development (TDD), Behavior-driven Development (BDD), Design Patterns, Continuous Deployment, REST, Functional Programming, Responsive Web Design (RWD), Prototype-based OOP, Management, Objectives & Key Results (OKRs)


HTML, CSS, TypeScript, HTML5, ECMAScript (ES6), CSS3, JavaScript, Ada, Sass, Java, PHP, C#, Less


Windows, MacOS, WordPress, Ubuntu Linux, Windows Server


MongoDB, MySQL, PostgreSQL


Website Performance, Mentorship, People Management, Web App Development, WCAG 2, Accessibility, SEO Audits, CTO, Web Accessibility, Accessible Rich Internet Applications (ARIA), Front-end Development, Architecture, QA Testing, Linux Servers, Customer Service, Elycharts, Team Mentoring, Scrum Master, Scaling, APIs, Website QA

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