Project Overview

This project showcases the engineering of a high-performance currency and cryptocurrency conversion platform. It provides users with up-to-date rates, which are maintained through automated background data fetching scheduled via Quartz.NET. For enhanced SEO, the application utilizes Next.js for Server-Side Rendering (SSR). Deployment relies on modern DevOps practices, including delivery to a Kubernetes cluster managed via Helm.

Key Technologies

• Backend: ASP.NET Core, C#, Quartz.NET
• Frontend: React, Next.js, Tailwind CSS
• Database: PostgreSQL, Entity Framework Core (with Migrations)
• Architecture: Clean Architecture, Domain-Driven Design (DDD) Principles
• DevOps: Docker, Kubernetes (K8s), Helm, GitHub Actions (CI/CD)
• External APIs: FlateRate (Fiat Currencies), CoinGecko (Cryptocurrencies)

Backend Architecture and Implementation

Architecting the backend involved using ASP.NET Core structured according to Clean Architecture principles, ensuring a robust separation of concerns and promoting maintainability.

Within this architecture, Domain-Driven Design (DDD) principles were applied; concepts like Entities and Value Objects (e.g., for Currency, CurrencyName) help accurately model the core domain.

A critical backend function is the scheduled acquisition of external data. This process is managed by Quartz.NET, which triggers background jobs to fetch fiat currency rates from FlateRate every 12 hours and cryptocurrency rates from CoinGecko every minute, ensuring data freshness without constantly polling external APIs.

For data persistence, the fetched USD-based rates are stored in a PostgreSQL database using Entity Framework Core. Schema changes are managed systematically via EF Core Migrations. The backend's primary role, therefore, focuses on the reliable, scheduled aggregation and storage of base currency data, serving it efficiently to the frontend.

Frontend User Interface

Building the user interface involved using React and Next.js. The strategic choice of Next.js enables Server-Side Rendering (SSR), significantly benefiting Search Engine Optimization (SEO). For styling, Tailwind CSS was employed, facilitating the rapid development of a clean and responsive interface with its utility-first approach.

A key responsibility delegated to the frontend is performing the calculation of cross-currency conversions on the client-side based on the USD-relative rates provided by the backend API; this design keeps the backend logic streamlined.

The user experience focuses on clarity and ease of use. Features include real-time display of the latest rates, an intuitive mechanism for selecting currencies and inputting amounts, full internationalization supporting six languages, and dynamic theme switching between light and dark modes. To manage component and application state, standard React patterns are utilized.

Deployment Automation and Infrastructure

A comprehensive DevOps workflow ensures automated and reliable deployments. To guarantee environmental consistency, both the backend service and the frontend application are packaged into Docker containers.

Deployment targets a Kubernetes (K8s) cluster for these containerized applications. Helm charts streamline the management of Kubernetes resources and the deployment process itself, enhancing predictability and simplifying updates.

Automation for the entire cycle is handled via a GitHub Actions CI/CD pipeline. Code commits automatically trigger builds, Docker image creation and registry pushes, followed by the deployment of new application versions to the Kubernetes cluster using Helm.

Conclusion

This Currency Conversion Platform demonstrates practical expertise in building performant, full-stack web applications. It effectively utilizes background job scheduling (Quartz.NET) for reliable data acquisition, leverages Next.js for SEO benefits via SSR, and implements efficient client-side logic for calculations. The architecture (Clean Architecture, DDD principles) and robust DevOps pipeline (Docker, Kubernetes, Helm, CI/CD pipeline) showcase the ability to engineer and deploy scalable, production-ready solutions with a focus on maintainability and automation.