Szymon – React, Node.js, Next.js

This is a benefit system for employees and a way for employers to lower their taxes. From the employers' side, it's a complex CRM with the ability to see tens of thousands of records in a table, create two different merchant accounts with two different dashboards, and synchronize its state with blockchain to meet legal requirements. From the employees' standpoint, it's a mobile app where they can send back tokens and get different benefits in exchange.

• Designed and optimized a scalable PostgreSQL (pSQL) database, enabling the system to handle tens of thousands of requests per second for rapid response times;
• Developed a smart contract and accompanying service to mirror transactions on the blockchain, ensuring transparency for legal reasons;
• Implemented Next.JS 14 with server and client-side architecture, achieving optimal performance;
• Built a mobile app using React Native for Android and iOS;
• Developed a responsive CRM interface that efficiently displays thousands of data rows without lag, enabling real-time insights.

A membership app for the major Polish fitness influencer. What started as a simple membership app project with workout videos, quickly grew in functionality to soon include also e-commerce, CRM for salespeople who called abandoned carts (surprisingly profitable), testing and optimizing paywall with superwall, etc.

• Deployed a Flutter app to Web, iOS & Android;
• Built the full e-commerce stack - email follow-ups, customer journey, shipping;
• Scaled the app to 5k users and $30k / mo revenue while maintaining 98% uptime;
• Integrated Stripe & Revenucat - subscription & product payments;
• Did A/B Testing for paywalls to maximize revenue.

Built a custom Shopify app to streamline order management for a growing e-commerce business.

• Designed and built a private Shopify app using Node.js and React to provide advanced order management features directly within the Shopify admin panel.
• Integrated the app with third-party APIs (e.g., shipping providers, payment gateways) using Shopify Admin API and GraphQL, enabling automated tracking updates and real-time order status syncing.
• Implemented robust filtering, sorting, and reporting features with React Table and Chart.js, providing the client with actionable insights into their sales and fulfillment processes.
• Utilized Shopify Webhooks to handle real-time order updates and sync changes seamlessly, ensuring data accuracy across all systems.
• Deployed the app on AWS with Docker and implemented OAuth-based authentication for secure access across multiple stores.

A research, psychology Single Page Application game to test user reaction times and feed the data to an AI algorithm.

• Created responsive frontend gaming experience using NextJS;
• Implemented PyTorch to teach the algorithm about user behavior;
• Implemented backend in Python.

It's a product that provides web2 companies with web3 capabilities, allowing them to airdrop NFTs to customers with simple API commands, as well as a professional dashboard where they can track activity. It comes with payments support and multi-chain support.

• Took the product from ideation to MVP;
• Managed a team of 2 other Full-Stack developers;
• Introduced fast iterations, due to CI/CD process that I've designed;
• Implemented multi-chain support, including Solana;
• Created custom Custodial Wallet solution using AWS and MPC cryptography.

Crypto currency service, which works similarly to Stack Overflow, with that difference, that for valuable answers, you get pay in crypto, and all of the content is translated into all of the supported languages.

• Introduced the mechanism to translate content to all languages in the world and display appropriate content depending on location/user preferences;
• Performed NLP processing;
• Implemented Elastic search to provide extra fast search recommendations.

General application for event management, ticket creation, dynamically generating iframes for sharing, and payments management.

• Created complex frontend with Next.js & chart.js;
• Created a fully responsive design;
• Integrated Stripe Payments;
• Added SQL database with Prisma;
• Added the ability to share events as iframes.

Application for covid tests management in restaurants. The whole process of making a covid test was integrated into an app, along with an AI algorithm that was checking the covid test result. On the other side there was a payment system integrated and an employee management panel.

• Integrated Payment using Stripe;
• Wrote complex, responsive views with different levels of authentication access in NextJS & Tailwind.

Automating process between gathering forms and sending them to the print. Details sent to the email through forms are picked up by a bot that sniffs the email inbox, filters information from the form, and saves it in the NoSQL database. On the frontend there was an app written in NextJS and pdf creator, allowing to download dynamically created letters.

• Configured Firebase;
• Communicated with NoSQL Database;
• Created Python bot sniffer;
• Created frontend with login;
• Connected frontend to backend;
• Dynamically created pdfs from data;
• Dockerized the whole app so it can work with different emails.

Trading bot based on AI predictions. Scrapper was hosted on Heroku as a Python bot, which every few hours scrapped YahooFinance for price data. It is then appended to the file on AWS S3. Then the data was used to train the machine learning model and based on that we were making price predictions.

• Configured scrapper and hosted it on Heroku;
• Created machine learning model with Tensorflow;
• Created plots with Matplotlib;
• Integrated python with Metatrader 5.