• ERP System: Designed and developed a full-featured ERP system from scratch using NestJS, PostgreSQL, Prisma, Next.js, TypeScript, and Docker, supporting human resources, customer management, finance, and other core business operations.
• Iconic Pro: Built a CMS-driven landing page platform from scratch using Next.js, PostgreSQL, Prisma, TypeScript, Tailwind CSS, and shadcn/ui, enabling administrators to manage page content, blog posts, and customer registrations without code changes.
• Infrastructure: Optimized deployment infrastructure using Docker, Nginx, Linux, GitHub Actions, and DigitalOcean, improving application performance, reliability, and operational cost efficiency.

Back-end:

• Built 6 microservices communicating asynchronously through RabbitMQ and gRPC.
• Designed and implemented a subscription service (Go, NestJS, PostgreSQL) supporting multiple payment providers.
• Implemented idempotent payment APIs and asynchronous webhook processing.
• Built a transactional outbox pattern with RabbitMQ for reliable event-driven communication.
• Implemented retry mechanisms with exponential backoff and dead-letter exchanges (DLX) for resilient message processing.
• Integrated Redis caching to reduce database load and improve response latency.
• Wrote 50+ unit and integration tests.

Front-end: Developed the frontend using Next.js, TypeScript, Tailwind CSS, and shadcn/ui.

Back-end:

• Developed a RESTful API for an incentive and rewards platform with Role-Based Access Control (RBAC), JWT-based authentication (access and refresh tokens), and API key authorization.
• Built the backend using Node.js and Express.js, integrating with Ethereum smart contracts through Ethers.js.

Smart Contract: Developed three reward token smart contracts based on the ERC-777 standard, extending ERC-20 functionality with advanced token transfer features.