Tomasz is available for hire

Tomasz Mularczyk

Verified Expert in Engineering

Front-end Developer

Warsaw, Poland

Toptal member since April 17, 2020

Expertise

Web Applications Web Development Front-end Responsive UI Responsive Web Apps ESLint Gatsby ECMAScript (ES6)HTML5 React Router Git Unit Testing Webpack Struts Development

Bio

Tomasz is a passionate front-end engineer who excels at creating responsive and rich websites. He's worked for small and medium companies, as well as for big corporations. Along with being quality-driven, Tomasz enthusiastically shares his skills and knowledge with his teammates and contributes to open-source projects.

Portfolio

Toptal Clients

JavaScript, React, TypeScript, GraphQL, Jest, Testing, CSS, HTML, Gatsby...

Kraken

React, Next.js, Jira, Figma, TypeScript, Cypress, Web Applications...

OLX Global

JavaScript, React, Next.js, CSS, Server-side Rendering (SSR)...

Experience

React - 5 years Front-end - 5 years Jest - 4 years Next.js - 4 years TypeScript - 3 years Webpack - 3 years Gatsby - 2 years Tailwind CSS - 2 years

Availability

Part-time

Preferred Environment

Jira, Slack, Trello, Figma, InVision, Zeplin, Visual Studio Code (VS Code), MacOS

The most amazing...

...project I've developed was an app that would let users import and edit 3D models directly into a browser.

Work Experience

Front-end Engineer

2021 - PRESENT

Toptal Clients

Developed an eCommerce website called Corroshop.com.
Worked on a booking app for a well-known automotive company. Fixed bugs in a legacy project and helped migrate the project to a newer version.
Helped fix bugs and rewrote the flight-booking app.

Technologies: JavaScript, React, TypeScript, GraphQL, Jest, Testing, CSS, HTML, Gatsby, Netlify, Web Applications, GitHub, Web Development, Mobile Web, Responsive UI, Responsive Web Apps, Lint, Slack, React Apollo, Apollo, Storybook, UI Development, ECMAScript (ES6), JSX, REST, DOM, APIs, Unit Testing, Landing Pages

Front-end Engineer

2022 - 2022

Kraken

Tested (E2E) critical user flows for the funding page with Cypress.
Tracked and fixed bugs using Jira as a reporting tool.
Fixed styling inconsistencies across different mobile browsers.

Technologies: React, Next.js, Jira, Figma, TypeScript, Cypress, Web Applications, Web Development, Mobile Web, Responsive UI, Responsive Web Apps, Lint, Slack, Data Structures, Storybook, UI Development, ECMAScript (ES6), JSX, REST, DOM, APIs, Unit Testing, Landing Pages

Front-end Engineer

2020 - 2021

OLX Global

Migrated part of the website to a new front-end stack in Next.js.
Contributed to the development of a new monetization framework.
Helped onboard new members to the team and contributed to overall knowledge sharing.

Technologies: JavaScript, React, Next.js, CSS, Server-side Rendering (SSR), Responsive Web Design (RWD), Analytics, TypeScript, Web Applications, Web Development, Mobile Web, Responsive UI, Responsive Web Apps, Lint, TSLint, Slack, Docker Compose, Data Structures, Storybook, UI Development, ECMAScript (ES6), JSX, REST, DOM, APIs, Unit Testing

Senior Front-end Developer

2019 - 2021

Netguru

Contributed to the development of a fintech investment platform that has over €100 million assets under management by this time.
Worked in a Scrum environment with a team of 20 developers. Constructed both admin and client SPA in React.
Refactored the app from JavaScrip to a TypeScript.
Implemented a previously desktop-only app to support mobile devices as well.
Made presentations of new features to the client and potential investors.
Migrated the whole app from a complicated Webpack configuration to a new framework.
Served as an active member of the company recruitment team.
Optimized components for maximum performance across a wide array of devices and browsers.
Delivered new versions of the product, frequently using integration and automation.

Technologies: Front-end, Axios, Mobile First, HTML5, HTML, Rollup.js, Webpack, Redux-Saga, SCSS, CSS-in-JS, Create React App, ESLint, Jira, Gatsby, Babel, Next.js, JavaScript, TypeScript, Git, Jest, CSS, React, Enzyme, Node.js, Redux, React Router, Tailwind CSS, Web Applications, GitHub, Web Development, Mobile Web, Responsive UI, Responsive Web Apps, Docker, Material UI, Lint, TSLint, React-Intl, Slack, Storybook, UI Development, ECMAScript (ES6), JSX, REST, DOM, Unit Testing, Landing Pages

Front-end Developer

2017 - 2019

Risen

Co-created an app that would allow editing of a 3D model in the browser.
Worked on a platform for companies and influencers. Added new features, updated the project dependencies, refactored legacy code, and optimized it to work faster.
Helped onboard new developers with their assignments and kept an eye on code quality.
Established standards, flow, and the main stack for the front-end area for a quickly growing company.
Helped our client get a government subsidy of close to $250,000.

Technologies: Front-end, Axios, Mobile First, HTML5, HTML, Rollup.js, Flow, Webpack, React-Intl, Redux-Saga, SCSS, CSS-in-JS, Styled-components, Create React App, Clean Code, ESLint, Jira, Gatsby, Babel, Next.js, JavaScript, TypeScript, Git, Jest, CSS, React, React Router, Redux, Web Applications, GitHub, Web Development, Mobile Web, Responsive UI, Responsive Web Apps, Material UI, Bootstrap, Lint, Chart.js, ECMAScript (ES6), JSX, DOM, Landing Pages

Junior Java Developer

2016 - 2016

netPR

Optimized and wrote unit/integration tests for crucial back-end endpoints using Mockito and other integrations tools.
Replaced legacy code that used the Struts framework to use the Spring framework.
Updated and replaced legacy dependencies and refactored JPQL with QueryDSL.
Took part in daily standups and weekly and planned sprints with the team using Jira.

Technologies: HTML5, HTML, Clean Code, ESLint, Jira, Git, Mockito, PostgreSQL, Hibernate, Spring, Java 8, Web Applications, MySQL

Experience

React Library Maintainer

https://www.npmjs.com/package/react-id-generator

I created a package for React apps that creates unique HTML IDs for better app accessibility. This package helps developers create components on the page easier without thinking of a new ID name. The code is open-sourced, has TypeScript support, and has a few thousand weekly downloads.

Rewrite of a React-based Responsive Project

https://www.npmjs.com/package/react-responsive

I have rewritten and updated a React-based, responsive project: a library that has 200,000 downloads/month. I updated the library to support server-side-rendering and testing more easily, I also solved the main user's requests which was support for the React Hooks feature.

Enter the World of Entertainment by Totalizator Sportowy

Our project introduced Totalface: an age verification platform based on the facial recognition of the company's customers. The system was supposed to work in online and offline channels. It also provides customer anonymity as we only store the information that the user is over 18 years old.
RESULT: We won the first prize in this hackathon category.
• https://hackyeah.pl/winners-2019/#Enter%20the%20world%20of%20entertainment%20by%20Totalizator%20Sportowy

Education

2012 - 2016

Bachelor's Degree in English Philology

University of Information Technology and Management - Rzeszów, Poland

Skills

Libraries/APIs

React Router, React, Redux-Saga, React-Intl, Rollup.js, Chart.js, Node.js

Tools

Create React App, Git, Webpack, Babel, JSX, Zeplin, InVision, Figma, Trello, Slack, Flow, GitHub, Jira, React Apollo, Docker Compose

Languages

HTML, HTML5, JavaScript, TypeScript, SCSS, CSS, ECMAScript (ES6), Java 8, GraphQL

Frameworks

Redux, Next.js, Jest, Tailwind CSS, Material UI, Bootstrap, Spring, Hibernate, Mockito, Cypress

Paradigms

Responsive, Clean Code, Unit Testing, Testing, REST, Responsive Web Design (RWD)

Platforms

Visual Studio Code (VS Code), MacOS, Docker, Netlify

Storage

Media Queries, PostgreSQL, MySQL

Other

Lint, Mobile First, Axios, Front-end, ESLint, TSLint, Styled-components, CSS-in-JS, Gatsby, Web Applications, Web Development, Mobile Web, Responsive UI, Responsive Web Apps, Storybook, UI Development, Data Structures, DOM, APIs, Landing Pages, Open Source, Apollo, Server-side Rendering (SSR), Analytics, Enzyme

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.

Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring