Projects & Case Studies
Real-world projects: payment gateway microservices, full-stack apps, Django backends, RAG systems and more.
J.P. Morgan Personal Investing — Back-End Engineer Mock Interview Pack
Format: 60-minute pair programming on HackerRank IDE, 1–2 business-logic problems, Java/Kotlin preferred. > Team context: Stock-market broker (Personal Investing platform). > Goal: Translate spoken business rules into cl
Read article →Payment Gateway - Q&A
What it is: ArgumentCaptor is a Mockito utility that captures the actual argument passed to a mocked method during execution, so you can inspect it afterwards.
Read article →Payment Gateway Challenge
This project is a Spring Boot application that implements a simple payment gateway based on the requirements from the challenge
Read article →How to fulfill everything described in README.md
This document maps each commitment in the project README.md to concrete actions and suggested code. The upstream interview template is payment-gateway-challenge-java; it also states not to change imposters/ or .editorcon
Read article →Microservices Teaching Guide — Payment Gateway
A complete, hands-on course for refactoring a Spring Boot monolith into a production-grade microservices system, and deploying it to AWS. > > Source monolith: ../payment-gateway-challenge-java > Target system: this folde
Read article →Payment Gateway — Microservices Edition
A microservices reimagining of the payment-gateway-challenge-java Spring Boot monolith.
Read article →Architecture Decision Records (ADRs)
ADRs document why we made a decision, not just what we did. We use the Michael Nygard format. Each ADR has a status: Proposed, Accepted, Superseded.
Read article →AWS Deployment — Step by Step
Companion to ../MICROSERVICES_TEACHING_GUIDE.md §15. > > Goal: take the eight microservices in this repository from docker compose up to a production-grade deployment on AWS using ECS Fargate, RDS, MSK, ElastiCache, ALB,
Read article →CI/CD with GitHub Actions
Companion to ../MICROSERVICES_TEACHING_GUIDE.md §16.
Read article →Observability
Companion to ../MICROSERVICES_TEACHING_GUIDE.md §12. > > Distributed systems are only as good as your ability to understand them. This document covers logs, metrics, traces, dashboards, and alerts.
Read article →Terraform — Payment Gateway Microservices on AWS
Reference IaC for the AWS deployment described in > ../../docs/02-aws-deployment.md. > > Status: skeleton. It compiles (terraform validate) and demonstrates the > module structure. Before applying it to a real AWS accoun
Read article →Payment Gateway - Design Documentation
This project implements a Payment Gateway API that allows merchants to process card payments and retrieve payment details. The gateway validates incoming payment requests, forwards valid payments to an acquiring bank sim
Read article →Florence Hotel Website (Flask)
This project is a Flask implementation of the Florence hotel frontend based on florence_hote.html.
Read article →Run and deploy your AI Studio app
This contains everything you need to run your app locally.
Read article →Deploy PawMatch to AWS EC2 (Ubuntu)
This guide covers syncing the Next.js frontend and Flask backend to an EC2 instance, running them under systemd, and using nginx (with existing Let’s Encrypt certs) so HTTPS on port 443 serves the site while the app list
Read article →PawMatch Backend API
A Flask-based backend API for the PawMatch cat matching and health analysis platform.
Read article →fp_fixed — README
This is a Next.js project bootstrapped with create-next-app.
Read article →Password CRUD Demo Application
A demonstration web application for password CRUD operations with plain text storage (demo purposes only).
Read article →Software Requirements Specification (SRS)
Product: Password CRUD (Next.js + Express.js + Prisma + SQLite) – Plain Password Demo Version: 1.1 Date: 29-Aug-2025 Author: ChatGPT (“Cathy”)
Read article →Android Development Exercises
Remember: The best way to learn Android development is by building apps. Use these exercises as stepping stones to create your own projects!
Read article →Android App Development with Kotlin - Learning Guide
Explanation: lateinit var: Declares a variable that will be initialized later (common in Android) var: Mutable variable (can be changed) val: Immutable variable (cannot be changed after initialization)
Read article →Android Development Learning Path
Week 1 Deliverables: Working Android Studio setup Basic Kotlin knowledge Understanding of Android project structure First modifications to the Blackjack app
Read article →Blackjack (21) Overview
Blackjack (21) Overview Blackjack, also known as 21, is a popular card game often played in casinos. The goal is to have a hand value close to 21 without going over.
Read article →Kotlin Syntax Quick Reference
This quick reference covers the most important Kotlin concepts you'll encounter in Android development. Practice these patterns and you'll be well on your way to becoming proficient in Kotlin!
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