ReactJS

In cooperation with Salestube, copyrights belongs to Salestube

A React-based web application designed for clients and researchers to model financial outcomes using historical data and customizable scenarios. The app supports role-based access, scenario saving, and data export features.

Tech description:

• Supported two user roles: clients (limited access to own projects) and researchers (admin access to all data)
• Enabled creation, editing, saving (private/public), and exporting of multiple forecasting scenarios
• Developed advanced validation and visual tracking of large, complex datasets to ensure data integrity
• Implemented on-demand backend calculations triggered by users for secure, confidential predictive modeling
• Delivered a responsive, performant UI to handle dense data tables with clear change indicators

Contribution:
Sole Frontend Developer — responsible for frontend architecture and integration with backend services.

React, Firestore, Material UI

Live site:

ReactJS

In cooperation with Salestube, copyrights belongs to Salestube

Designed and built a complex internal web application to manage biannual customer satisfaction surveys. The platform supported multiple user roles — including clients, account leaders, executives, and developers — each with tailored access levels. I led the project architecture and UI design, integrating Google Sheets-based configuration workflows (via Apps Script) with Firestore for dynamic survey generation. The app featured both public and secured views, with role-based access to survey links and results, ensuring clear data segmentation and secure access control.

Contribution:

• 100% design
• 100% architecture
• 100% application

React, Firestore, Google Apps Script, Material UI

Live site:

ReactJS, Rowy, Typescript

In cooperation with Salestube, copyrights belongs to Salestube

Adapted and extended Rowy, an open-source React+TypeScript low-code backend, to develop a secure, user-friendly internal tool for data management, workflow automation, and validation. Accelerated project delivery by leveraging an open-source base, providing the team with a tailored, secure, and intuitive data management solution.

Tech description:

• Created a new hybrid user role combining admin and viewer permissions with specific restrictions and allowances (e.g., controlled data categorization)
• Redesigned the UI by adding, hiding, and modifying components to meet project need
• Developed custom visual validation logic based on multi-column input conditions
• Delivered a polished, efficient tool saving development resources and improving internal workflows

Contributon:
Sole Frontend Developer — responsible for UI redesign, custom role creation, and functional enhancements.

ReactJS, Rowy, Typescript, Firestore

Live site:

Jinja2 templates, HTML, CSS

In cooperation with Salestube, copyrights belongs to Salestube

An internal web tool built with Flask and Jinja2 templates to automate file renaming and batch processing of zipped HTML files. Users upload zipped folders and configure transformation rules that guide content modification and file generation.

Tech description:

• Developed a dynamic, user-friendly frontend with Jinja2 and CSS to handle variable configuration inputs.
• Implemented robust validation logic adapting to diverse data and user setups.
• Collaborated closely with backend developer who handled file unzipping and content transformation.
• Delivered a tool that streamlined workflows, reduced manual errors, and saved significant time in file processing.

Contribution:
Frontend Developer — responsible for building the user interface and validation of complex, variable data inputs based on user configurations.

Live site:

ReactJS

A SPA (Single Page Application) designed in ReactJS created to learn and practise English irregular verbs.

Contribution:

• 100% design
• 100% frontend
• 100% backend
• 100% mobile version
• 100% responsive

ReactJS, CSS, HTML

Live site:

WordPress

Contribution:

• 100% design
• own theme
• 100% frontend
• 100% backend
• 100% mobile version
• 100% responsive

WP, Bootstrap 4, CSS, HTML, PHP, JS, jQuery

Live site:

Google Assistants

In cooperation with Salestube

• G2A
• Death Stranding

Live site:

Magento 2

In cooperation with Peexl

Contribution:

• 100% frontend bug fixing
• 50% home page
• 100% mobile version adjustments

Magento, Bootstrap 3, CSS, LESS, HTML

Live site:

WooCommerce

In cooperation with Peexl

Contribution:

• 100% frontend*
• 100% mobile version
• 100% own design based on graphics, logo and fonts provided by the client

*based on Avada Theme

WP, WooCommerce, CSS, HTML, PHP, Sass

Live site:

My very first webpage – far from perfect, !!!knowledge still under construction!!! 😉

Pure coding

Contribution:

• 100% design
• 100% frontend
• 100% backend
• 100% mobile version
• copyrights to all images belong to the author – Janusz Tworek

CSS, HTML, jQuery

Live site: