Nicholas – AWS, React, Python

A WebSocket API system designed with robust error and failure handling, leveraging Redux Saga for seamless integration into complex web applications. It supports advanced API behaviors, including ordered request handling and custom authentication protocols. This system has been effectively utilized to manage authentication and API endpoints in applications with high-performance requirements.

• Developed an API with redundancy and health-check mechanisms to manage unstable connections effectively;
• Implemented detailed logging to track user authentication steps, including email codes and cryptocurrency wallet challenge signing;
• Designed a seamless handshake process with rollback functionality and the ability to restart from any point after a disconnect;
• Wrote a suite of tests to ensure the system's robustness and compatibility across different platforms and architectures.

This platform enables micro-consulting through chat, where users can set their own pricing for messages and monetize their expertise. Users can use their balance to chat with other professionals or withdraw it directly. The project covers a complete development stack, including frontend, backend, smart contracts, and task queue management, offering a seamless experience for both service providers and clients.

• Designed and developed the entire application, including both frontend and backend systems;
• Created the application’s design, ensuring a seamless user experience;
• Deployed the application to production environments;
• Implemented extensive end-to-end tests to ensure system reliability and performance.

A decentralized finance (DeFi) platform focused on creating an automated market for interest rate swaps. The project involved designing and implementing a user-friendly interface, developing a subgraph to track blockchain events, and building a web3 SDK to enable seamless integration with the platform.

• Led the implementation of frontend, backend, and graph database smart contract event management;
• Managed the setup and configuration of smart contract event tracking;
• Resolved several technical challenges, including establishing an efficient event management system.

An offline Bitcoin wallet designed for secure transaction creation and signing. The system also supported encrypting and decrypting secure messages using advanced cryptographic methods. The cryptographic implementation leveraged low-level algorithms to provide both symmetric and asymmetric encryption capabilities for secure communication.

• Designed and implemented an offline Bitcoin wallet capable of creating and signing transactions;
• Developed cryptographic systems in Python 3, utilizing SHA256 and AES encryption for secure operations;
• Extended symmetric encryption functionality to support asymmetric encryption for secure messaging;
• Enabled secure message encryption and decryption using the wallet's cryptographic features.

An application was developed to address the issue of online cart abandonment, where customers add items to their shopping cart but fail to complete the purchase. As part of the solution, a plugin for Shopify was created to enable upselling opportunities. The plugin, built using React, was seamlessly integrated into the Shopify platform to enhance user experience and drive conversions.

• Designed and implemented a drag-and-drop interface for building upsell UIs, enabling merchants to upload images and link products;
• Developed a smart matching system to offer specific products based on the contents of a customer’s cart;
• Ensured smooth error handling to maintain a seamless customer experience;
• Integrated error reporting and logging using Sentry for proactive issue resolution;
• Enabled the creation of multiple upsells per purchase to maximize revenue opportunities;
• Built a full customization system for merchants to configure their upsell workflows;
• Wrote end-to-end (e2e) tests to ensure functionality and reliability.