
Tomasz Stefaniak
Verified Expert in Engineering
Software Developer
San Francisco, CA, United States
Toptal member since June 19, 2017
Tomasz is a full-stack engineer 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 at a world-class university in London, he's very comfortable with the English language.
Portfolio
Experience
- React - 7 years
- JavaScript - 7 years
- TypeScript - 5 years
- Redux - 4 years
- CSS3 - 4 years
- Vue - 3 years
- React Router - 2 years
- Python - 2 years
Availability
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
Software Engineer
Freelance Clients
- Developed a custom Vue/Vuetify/Pinia front end and wrote automated Cypress tests to provide stability for its core functionalities.
- Fixed multiple bugs and added new functionalities to a complex Chrome extension written in React used by a VC company to research thousands of startups.
- Migrated a complex Chrome extension used by a VC company to research thousands of startups from JavaScript to TypeScript.
- Developed a React dashboard and configured an Amazon Timestream database with an AWS AppSync back end for an IoT company. Also set up DynamoDB schemas and worked with AWS IoT messages.
Full-stack Engineer | Tech Lead
Polygon
- Oversaw the development of multiple front-end libraries.
- Set up the front-end tests and integrated them into a CI/CD pipeline, improving the app's stability and significantly fewer user-facing bugs.
- Helped refactor FastAPI back-end code to follow best practices.
Tech Lead | Software Engineer
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, then led the new developers in high-stakes projects.
- Managed developers from 3rd-party companies and coordinated multiple high-stakes projects.
Software Engineer via Toptal
MintDice
- Developed the front end for a cryptocurrency gaming website used by over 100,000 visitors.
- Set up automated testing with Jest to improve the app's stability and prevent customer-facing bugs.
- 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.
Front-end Developer | Tech Lead
Pioner Labs
- Helped develop the front end of an eCommerce store for a leading Norwegian fashion retailer.
- Worked extensively with React Hooks, functional components, and TypeScript to build reusable storefronts.
- Contributed to an internal library of reusable React components used to develop storefronts.
- Served as a tech lead for a back-office product, managing online and offline promotional campaigns.
- Selected for an internal leadership coaching program.
Front-end Engineer
Paladin
- Built multiple customer-facing features for a legal tech product used by lawyers to provide pro-bono services. Built using React, Redux, and Material UI.
- Collaborated closely with the core team and the CTO to address bugs and improve user experience.
- Contributed to the Django/Python back end for the customer dashboard and admin panel.
Front-end Engineer
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. This was used as a landing page to drive ticket sales for a series of concerts.
Co-founder | Full-stack JavaScript Developer | CTO
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.
Project Manager
NUMA Paris
- Supported the startup accelerator team as a project manager in processing and analyzing hundreds of startup applications.
- Analyzed past application data and created tools for internal use, such as a searchable database of startups or a tool for startup evaluation. This was used to rate hundreds of startups, some of which the company eventually invested in.
- Organized the kick-off event for a new startup class.
iOS Developer | Co-founder
Ocean London
- Helped develop a Swift/iOS app to assess the user's psychological profile and then rate places in London and add them to our database.
- Designed a recommendation algorithm using a version of the Big Five Personality Test and employing a linear regression algorithm and a rating system to map the psychological profile to user preferences.
- Managed 3rd-party outsourcing companies contracted to develop the applications' back-end.
Experience
Panda HSK
Rank Anything
https://www.rankanything.online/The website is integrated with the Firebase SDK, with email and SMS verification. It was built with Next.js, Tailwind CSS, and PostgreSQL.
Sanity Media
https://www.sanity.media/Emojify 🎉
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
Chilla
Flowcat
https://flowcat.co/For example, you can generate an image with one model, modify it with another model, and then remove the background with yet another one.
Education
Bachelor's Degree in Arts and Sciences: Sciences and Engineering
University College London (UCL) - London, UK
Certifications
Management Essentials
Harvard Business School Online
Skills
Libraries/APIs
Node.js, Vue, React, Liquid, React Router, REST APIs, React Redux, Vue 3, React Testing Library, 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, AWS SDK, Figma
Languages
ECMAScript (ES6), HTML, CSS, TypeScript, CSS3, JavaScript, SCSS, HTML5, Python, GraphQL, PHP, Objective-C, Less, Sass, Swift, SQL, Markdown
Frameworks
Redux, Next.js, React Native, Jest, Vuetify, Nuxt.js, Cypress, Material UI, Tailwind CSS, Express.js, iOS SDK, Django, Vue SSR
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, Vercel, Visual Studio Code (VS Code), Shopify, Amazon Web Services (AWS), OS X, Heroku, iOS, Meteor, Mapbox, Firebase, Android, Azure, AWS Lambda, Google Cloud Platform (GCP), Azure Functions, Docker, DigitalOcean, AWS IoT
Industry Expertise
Project Management
Storage
NoSQL, MongoDB, Databases, JSON-LD, Cloud Firestore, Google Cloud, Amazon S3 (AWS S3), Redis, PostgreSQL, Amazon DynamoDB
Other
Responsive Web Apps, Web Development, Responsive UI, Front-end, User Interface (UI), API Integration, Front-end Development, Code Review, UI Components, Web Applications, eCommerce, Team Leadership, Full-stack, WebSockets, User Experience (UX), APIs, Airtable, MERN Stack, Technical Leadership, 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, Application State Management, Design Systems, Web Usability, Back-end, Serverless, SaaS, Technical SEO, OpenAI GPT-4 API, Web Dashboards, Leadership, Test Case Development, 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, Vercel Analytics, SOAP, Generative Artificial Intelligence (GenAI), GitHub Actions
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