Tomasz Stefaniak, Developer in Gdynia, Poland
Tomasz is available for hire
Hire Tomasz

Tomasz Stefaniak

Verified Expert  in Engineering

Software Developer

Location
Gdynia, Poland
Toptal Member Since
June 19, 2017

Tomasz is a full-stack engineer and passionate about web development. He specializes in JavaScript frameworks (Node.js, Express.js, React, Redux, and Vue). Before entering the JavaScript ecosystem, he developed iOS and Android apps. Tomasz has worked in teams and on solo projects and knows the importance of good communication. Having studied in London at a world-class university, he's very comfortable with the English language.

Portfolio

Freelance Clients
Vue 3, Pinia, TypeScript, React, Chrome Extensions, Redux...
Polygon
Vue, Vuetify, Nuxt.js, SCSS, TypeScript, Python, CSS3, HTML5, Cypress...
GRG Studios
React, Vue, Next.js, Sass, TypeScript, JavaScript, Redux, CSS3, HTML5...

Experience

Availability

Part-time

Preferred Environment

Visual Studio Code (VS Code), Git, OS X

The most amazing...

...thing I've coded was a map of psychological profiles of different London boroughs based on 200,000 geolocated tweets analyzed with IBM Watson API.

Work Experience

Front-end Engineer

2023 - PRESENT
Freelance Clients
  • Developed a custom Vue/Vuetify/Pinia front-end for a client and wrote automated Cypress tests for its core functionalities.
  • Fixed multiple bugs and added new functionalities to a complex Chrome extension written in React.
  • Migrated a complex Chrome extension from JavaScript to TypeScript.
Technologies: Vue 3, Pinia, TypeScript, React, Chrome Extensions, Redux, Application State Management, Design Systems, Web Usability, Material UI, Vuetify, AWS Amplify, Azure Functions, Serverless, API Development, Back-end Development

Full-stack Engineer | Tech Lead

2021 - 2023
Polygon
  • Oversaw the development of multiple front-end libraries.
  • Set up the front-end tests and integrated them into a CI/CD pipeline.
  • Helped refactor back-end code to follow best practices.
Technologies: Vue, Vuetify, Nuxt.js, SCSS, TypeScript, Python, CSS3, HTML5, Cypress, JavaScript, Git, Visual Studio Code (VS Code), CSS, Sass, Webpack, Responsive Web Apps, Team Leadership, Web Development, Responsive UI, GitHub, Front-end, Full-stack, WebSockets, HIPAA Compliance, User Experience (UX), User Interface (UI), APIs, REST, HTML, SQL, Design, Technical Leadership, Project Management, API Integration, Google SEO, SEO Tools, Seos, Amazon Web Services (AWS), Admin Panels, Amazon S3 (AWS S3), Dashboards, Search Engine Optimization (SEO), Web Performance Optimization (WPO), Front-end Development, Responsive Layout, Full-stack Development, Web UX, REST APIs, Mobile, Remote Team Leadership, Code Review, ECMAScript (ES6), Zapier, Google Analytics, AWS Lambda, UI Components, Kanban, UX Design, CI/CD Pipelines, HubSpot CRM, Architecture, Software Architecture, Application State Management, Design Systems, Web Usability, Node.js, Back-end, Docker, Scheduling, API Development, Back-end Development

Tech Lead | Software Engineer

2020 - 2021
GRG Studios
  • Contributed to a range of projects, mostly relying on React, TypeScript, Next.js, and Vue.
  • Managed the hiring process for multiple software development positions.
  • Managed developers from third-party companies and coordinated multiple projects.
Technologies: React, Vue, Next.js, Sass, TypeScript, JavaScript, Redux, CSS3, HTML5, React Router, Jest, Management, BEM, Git, Visual Studio Code (VS Code), CSS, SCSS, Webpack, Responsive Web Apps, Team Leadership, Web Development, Responsive UI, GitHub, GitLab, Front-end, Full-stack, User Experience (UX), User Interface (UI), APIs, REST, HTML, MERN Stack, Technical Leadership, Project Management, API Integration, Google SEO, SEO Tools, Seos, Search Engine Optimization (SEO), Web Performance Optimization (WPO), Front-end Development, Responsive Layout, Web UX, REST APIs, Mobile, Remote Team Leadership, Code Review, ECMAScript (ES6), Google Analytics, Kanban, UX Design, CI/CD Pipelines, Architecture, Software Architecture, Web Usability, Node.js

Software Engineer

2019 - 2021
MintDice
  • Developed the front end for a cryptocurrency gaming website with a complex Redux state and WebSockets.
  • Wrote tests for the application using the Jest testing library.
  • Migrated the website from a static website to Next.js to optimize performance.
  • Optimized SEO using JSON-LD and React Helmet library.
  • Built a blog connected to a CMS and created a custom React component for rendering blog content.
Technologies: TypeScript, React, JavaScript, CSS3, HTML5, Redux, React Router, Jest, Next.js, Material UI, Styled-components, JSON-LD, Sockets, Git, Visual Studio Code (VS Code), CSS, Sass, SCSS, BEM, Webpack, Responsive Web Apps, React DnD, Web Development, Responsive UI, GitHub, GitLab, Front-end, WebSockets, User Experience (UX), User Interface (UI), APIs, REST, HTML, MERN Stack, Design, Technical Leadership, Project Management, API Integration, Google SEO, SEO Tools, Seos, Search Engine Optimization (SEO), Web Performance Optimization (WPO), Front-end Development, Responsive Layout, REST APIs, Mobile, Remote Team Leadership, Code Review, Casino Games, ECMAScript (ES6), UI Components, Kanban, CI/CD Pipelines, React Redux, Material Design, Application State Management, Web Usability, Back-end

Front-end Developer | Tech Lead

2019 - 2019
Pioner Labs
  • Helped develop the front end of an eCommerce store for a Norwegian fashion retailer.
  • Worked extensively with React hooks, functional components, and TypeScript.
  • Contributed to an internal library of reusable React components.
  • Worked as a tech lead for a back-office product managing online and offline promotional campaigns.
  • Selected for an internal leadership coaching program.
Technologies: Node.js, TypeScript, React, JavaScript, CSS3, HTML5, GraphQL, Redux, React Router, Jest, Management, Git, Visual Studio Code (VS Code), CSS, Sass, SCSS, Responsive Web Apps, Team Leadership, Web Development, Responsive UI, GitHub, Front-end, User Experience (UX), User Interface (UI), APIs, REST, HTML, MERN Stack, Technical Leadership, Project Management, API Integration, Admin Panels, Dashboards, Front-end Development, Responsive Layout, Full-stack Development, REST APIs, Mobile, Remote Team Leadership, Code Review, ECMAScript (ES6), UI Components, Storybook, Kanban, CI/CD Pipelines, React Redux, Design Systems, Web Usability, Back-end, Prisma

Front-end Engineer

2018 - 2019
Paladin
  • Built multiple customer-facing features using React, Redux, and Material UI.
  • Worked closely with the core team and the CTO to address bugs.
  • Contributed to the Django/Python back end when needed.
Technologies: React, HTML, CSS, JavaScript, Git, Material UI, Python, Django

Front-end Engineer

2017 - 2019
Freelance Clients
  • Built a ticket booking service using React and Mapbox for a Mexican travel agency.
  • Created and adjusted multiple Shopify stores for various clients.
  • Developed a complex React and Redux application from scratch for a company in the gaming and gambling industry.
  • Helped document a complex React front end for a cryptocurrency company.
  • Built a Vanilla HTML and CSS website for a company in the entertainment industry.
Technologies: Leaflet, Mapbox, React, TypeScript, Liquid, Shopify, JavaScript, eCommerce, MongoDB, Git, CSS, Sass, jQuery, SCSS, Redux-Saga, Responsive Web Apps, GraphQL, React DnD, Web Development, Responsive UI, GitHub, Front-end, User Experience (UX), User Interface (UI), APIs, REST, HTML, MERN Stack, Design, Project Management, API Integration, Google Cloud, Admin Panels, Dashboards, Search Engine Optimization (SEO), Front-end Development, Responsive Layout, Full-stack Development, Web UX, REST APIs, Mobile, Code Review, Casino Games, ECMAScript (ES6), Zapier, Kanban, Google Cloud Platform (GCP), Application State Management, Web Usability, Mapbox API

Co-founder | Full-stack JavaScript Developer | CTO

2016 - 2017
Bazzah
  • Built an interactive map of independent fashion design and gourmet food producers in Rio de Janeiro as an MVP of an online marketplace platform using Meteor, MongoDB, and React.
  • Developed a producer-facing dashboard for managing products, orders, and money withdrawals.
  • Created a quick set-up service with six steps (breadcrumbs) to ensure all new sellers have their profiles completely filled in and have at least one product to sell before being approved on the marketplace.
Technologies: MongoDB, Mapbox, ECMAScript (ES6), SCSS, React Router, Redux, React, Meteor, JavaScript, CSS3, Vue, Git, CSS, Responsive Web Apps, Web Development, Responsive UI, GitHub, Front-end, Full-stack, User Experience (UX), User Interface (UI), APIs, REST, HTML, Design, Technical Leadership, Project Management, API Integration, Admin Panels, Dashboards, Front-end Development, Responsive Layout, Minimum Viable Product (MVP), Web UX, REST APIs, Mobile, Code Review, Google Analytics, Kanban, UX Design, Architecture, Software Architecture, React Redux, Application State Management, Web Usability, Mapbox API, NoSQL, API Development

Project Manager

2015 - 2016
NUMA Paris
  • Supported the startup accelerator team as a project manager in processing and analyzing applications.
  • Analyzed past application data and created tools for internal use, such as a searchable database of startups or a tool for startup evaluation.
  • Organized the kick-off event for a new startup class.
Technologies: React, Meteor, CSS, HTML, PHP, Responsive UI, JavaScript, GitHub, Front-end, Full-stack, User Interface (UI), Design, Project Management, API Integration, Front-end Development, Responsive Layout, Web UX, REST APIs, Mobile, Zapier, Kanban, UX Design

iOS Developer | Co-founder

2014 - 2015
Ocean London
  • Co-founded Ocean while still studying at UCL.
  • Implemented a recommendation algorithm by analyzing the user’s psychological profile using a version of the Big Five Personality Test and employing a linear regression algorithm and a rating system to map psychological profile to particular preferences. For example, what’s the probability that a user with high openness score will like a restaurant given that it’s been described as "underground"?
  • Designed the algorithm that governed the app and together with other developers built the mobile app in Swift.
Technologies: Xcode, Swift, Objective-C, Design, Mobile Development, Technical Leadership, Project Management, API Integration, Mobile Apps, Front-end Development, Responsive Layout, Minimum Viable Product (MVP), Web UX, REST APIs, Mobile, Code Review, iOS, Kanban, UX Design, Architecture, Software Architecture

Panda HSK

Panda HSK is a Chinese learning app that I've designed and coded. It offers three study modes for practicing the words and phrases that appear in the HSK 1 Chinese exam. It's built with React Native, Redux, and TypeScript.

Emojify 🎉

Emojify was an emoji-based URL shortener. It let you shorten links using one of 75 single-emoji domains such as http://🦍.tk, http://🍾.cf, http://🍹.cf etc. It was featured on the front page of Product Hunt.

It was built with React and React Router for the front end. On the back end, it used Node.js with Express.js and Mongoose. It offered 75 different domains and was hosted on Google Cloud buckets.

Bazzah Producer Panel

Bazzah is an online marketplace for independent fashion producers. The producers use the panel to manage their stores with the ability to add and edit products, product images, and prices. Users can also edit store descriptions, logos, and cover images, and see their account balances and request the withdrawal of funds.

Chilla

A location-based news app built with React Native that allows users to create photo stories and others to react to other users' stories with emojis. I used Node.js with Mongoose and MongoDB with geospatial queries for the back end and implemented anonymous user accounts with Passport.js and Firebase.

Sanity Media

https://www.sanity.media/
A social network built with Next.js, React, Redis, MongoDB, OpenAI, and Amazon Cognito. It's a side project that I developed in my free time. The mechanics are similar to Twitter, except there is a minimum, instead of a maximum, character count, and users are only allowed to post once a day to encourage thoughtful discussion. There is also a live chat.

Languages

ECMAScript (ES6), HTML, CSS, TypeScript, CSS3, JavaScript, SCSS, HTML5, Python, PHP, Objective-C, Less, Sass, Swift, GraphQL, SQL, Markdown

Frameworks

Redux, Next.js, React Native, Jest, Vuetify, Nuxt.js, Cypress, Material UI, Tailwind CSS, Express.js, iOS SDK, Django

Libraries/APIs

Vue, React, Liquid, Node.js, React Router, REST APIs, React Redux, Recompose, jQuery, Redux-Saga, Leaflet, Sockets, React DnD, Firebase Web SDK, AWS Amplify, Mapbox API, API Development

Tools

GitHub, Webpack, Adobe Illustrator, GitLab, Seos, Google Analytics, Git, Xcode, Zeplin, Mongoose, Firebase Authentication, Expo, Amazon Cognito, Zapier, Prisma

Paradigms

Kanban, BEM, Agile, Management, REST, Search Engine Optimization (SEO), Web Performance Optimization (WPO), Responsive Layout, HIPAA Compliance, Mobile Development, Web UX Design, UX Design

Platforms

Mobile, Visual Studio Code (VS Code), Shopify, OS X, Heroku, iOS, Meteor, Mapbox, Firebase, Android, Amazon Web Services (AWS), Azure, AWS Lambda, Google Cloud Platform (GCP), Azure Functions, Docker, DigitalOcean

Other

Responsive Web Apps, Web Development, Responsive UI, Front-end, User Interface (UI), Front-end Development, Code Review, UI Components, eCommerce, Team Leadership, Full-stack, WebSockets, User Experience (UX), APIs, Airtable, MERN Stack, Technical Leadership, API Integration, Google SEO, SEO Tools, Mobile Apps, Admin Panels, Dashboards, Full-stack Development, Minimum Viable Product (MVP), Web UX, Remote Team Leadership, Casino Games, CI/CD Pipelines, Architecture, Software Architecture, Vue 3, Application State Management, Design Systems, Web Usability, Back-end, Serverless, Machine Learning, Styled-components, Design, Cross-platform App Development, Storybook, HubSpot CRM, Artificial Intelligence (AI), Material Design, Pinia, Chrome Extensions, Videos, Scheduling, Back-end Development, OpenAI

Industry Expertise

Project Management

Storage

MongoDB, Databases, JSON-LD, Cloud Firestore, Google Cloud, Amazon S3 (AWS S3), Redis, NoSQL, PostgreSQL

2012 - 2015

Bachelor's Degree in Arts and Sciences: Sciences and Engineering

University College London (UCL) - London, UK

DECEMBER 2019 - PRESENT

Management Essentials

Harvard Business School Online

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.

1

Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3

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