Wissanu Rayayoi - Software Engineer Portfolio

Experience

Digio (Thailand) Co., Ltd.

Internship

Web Developer Intern

Apr 2025 - Oct 2025

Core Responsibilities & Achievements:

1Assisted in maintaining the admin portal of Mobile Banking Application by implementing features and resolving defects based on client requirements.

2Developed unit tests using Jest to ensure code quality while actively studying the existing project architecture.

3Integrated DigiPay (payment gateway) into the DigiShop project(Co-op project) to handle secure payment flows.

4Studied financial payment workflows to design and successfully implement solutions on personal projects.

Selected Projects

Nida

2026

E-Commerce Platform for Fashion Brand

• Architected a scalable Turborepo Monorepo unifying Next.js Storefront, React Admin, and dual NestJS APIs.

• Implemented BullMQ & Redis delayed queues for automated unpaid order cancellation, restocking, and fulfillment timeouts.

• Implemented Dual-Token authentication with Token Family Rotation, replay attack detection, and multi-device revocation.

• Developed special features for the admin management system, such as Pre-Order reservation quotas to manage reservations, coupon abuse-prevention, and pro-rated net cost partial refunds.

Turborepo

Next.js

NestJS

PostgreSQL

Prisma

Redis BullMQ

Docker

TypeScript

TailwindCSS

View Details

P-Wallet

2026

E-Wallet & Double-Entry Ledger System

• Developed the financial transaction processing engine with Spring Boot and Hibernate within a double-entry ledger architecture.

• Eliminated database transaction deadlocks under heavy loads by implementing a lexicographical UUID lock-sorting protocol.

• Enhanced mobile app performance and reduced API overhead by leveraging TanStack Query for caching and Zustand for lightweight global authentication state management.

• Decoupled background email notifications and KYC verification updates asynchronously using Apache Kafka workers.

Java Spring Boot

NestJS

React Native

TanStack Query

Zustand

Next.js

PostgreSQL

Redis

Kafka AWS

Docker

View Details

StudyBuddy

2026

Student Matching & Curated Co-Working Space Directory

• Developed the multi-step Onboarding form using a persistent RegistrationContext with LocalStorage data recovery to assure smooth signup flows.

• Designed and developed the primary student profile card component showcasing student details, schedules, and study styles clearly.

• Built the Recommended Study Places directory featuring curated categories, toggle-ready facility filters, suggestions query, and toggle favorite capabilities.

• Implemented a real-time WebSocket chat system leveraging NestJS backend ChatModule supporting pinned messages, edits, reactions, and a 1-minute unsend window.

• Designed the dynamic Landing Page featuring customized call-to-action routing based on user registration and profile completion states.

Next.js

NestJS

TypeScript

Supabase

PostgreSQL

View Details

DigiShop

2025

Multi-Vendor E-Commerce & Payment Gateway Demo

• Designed and built the multi-vendor Merchant portal (inventories, orders) and Admin portal (RBAC, approvals) on a Client-Server architecture using Next.js 15 and Express.js.

• Integrated the DigiPay Payment Gateway API to process approved voids and settled refunds.

• Protected administrative APIs and workspaces using asymmetric RSA cryptographic JWTs and Role-Based Access Control (RBAC).

• Developed an administrator onboarding invitation workflow utilizing secure validation tokens and SendGrid API.

• Containerized services with Docker and deployed via Railway (Express Backend, MySQL, Redis) and Vercel (Next.js Frontend).

Next.js