IT Application Development Specialist at Circle K Vietnam
Nguyen Phu Cuong
Backend Development / System Integration / API & Database Engineering
I build backend and middleware systems that connect ShopeeFood, GrabMart, POS, CMS, e-commerce flows, webhooks, message queues, cache layers and operational data at Circle K Vietnam.
C#
.NET
Kafka
RabbitMQ
Redis
PostgreSQL
Docker
Technology stack
Tools I use to connect APIs, queues, data and business systems.
The stack moves around backend services, integration middleware, operational databases, event pipelines, DevOps basics and internal AI experiments.
Backend
Integration
Circle K Vietnam
C#
ASP.NET Core
EF Core
LINQ
REST API
Background Services
MySQL
PostgreSQL
Redis
SQLite
Kafka
RabbitMQ
Docker
Nginx
NestJS
React
Ollama
Qdrant
ChromaDB
RAG Systems
About me
Backend engineer focused on real systems, real load and real production failures.
My work leans toward backend development, system integration, API development, database engineering, middleware development, e-commerce and food delivery integration, internal business systems and practical DevOps.
I regularly handle integration flows between Grab, Shopee, POS, CMS and internal services: API design, background jobs, async processing, data synchronization and production debugging across Kafka, RabbitMQ, Redis, PostgreSQL, MySQL, network, SSL and webhook layers.
Technical expertise
Engineering stack
Backend development
C#, .NET, ASP.NET Core, Entity Framework Core, LINQ, REST API, background services and dependency injection.
ShopeeFood APIGrabMart APICMS APIPOS
API
Database engineering
MySQL, PostgreSQL, Redis, SQLite, query optimization, migration, sequence handling, bulk delete, cache design and index troubleshooting.
PG to MySQLData syncRedis cache
Message queue & events
Kafka, RabbitMQ, consumer troubleshooting, producer development, retry logic, order processing and stock synchronization.
Kafka consumerRabbitMQRetry flow
AI / LLM research
Ollama, ChromaDB, Qdrant, LangChain, LlamaIndex, local AI chat, document Q&A, internal knowledge search and RAG systems.
OllamaQdrantRAGVector DB
Web development
Node.js, NestJS, ExpressJS, React, Vite and WordPress plugin development for internal business workflows.
NestJSReactWordPress plugin
DevOps / infrastructure
Docker, Docker Compose, Linux Server, Windows Server, DNS, Nginx, SSL/TLS, IP whitelist and Kafka deployment.
DockerNginxSSL/TLSLinux
Featured projects
Core project work
ShopeeFood
ShopeeFood Integration Project
Menu sync, category sync, topping sync, stock sync, merchant mapping, store onboarding, order receiving, realtime webhooks and status synchronization.
shopeefood.menushopeefood.order.NETKafkaRedis
GrabMart
GrabMart Integration
Menu sync, stock sync, order submit/update/cancel, promotion mapping, store information, delivery hour, pause store, special hour and campaign sync.
.NETRabbitMQPostgreSQLCampaign
Circle K
CK Central Platform
Central platform work across CMS, portal, menu management, order management, Redis cache and Elasticsearch.
.NETRedisElasticCMS
Recruitment
Circle K Recruitment System
Recruitment website, WordPress plugin, candidate form, webhook integration, NestJS backend, authentication and HMAC validation.
NestJSWordPressPostgreSQLHMAC
RedInvoice
RedInvoice validation
Validation logic for electronic invoices: email, tax code, customer information and Vietnamese/English forms.
.NETMySQLValidation
Internal AI
Internal AI Assistant
Internal chatbot, company knowledge base, AI document search and RAG system experiments with local LLM and vector databases.
OllamaChromaDBQdrantPython
System strengths
Where I create the most value
Circle K
Grab
Shopee
POS
CMS
System integration
I connect Grab, Shopee, POS, CMS, external APIs and internal services into stable operational data flows.
Backend engineering
I design APIs, background jobs, async processing, retry logic and data synchronization for systems that run in production.
Production troubleshooting
I debug Kafka, RabbitMQ, Redis, PostgreSQL, MySQL, network, SSL and webhook issues when production needs a clear answer.
Experience
Career timeline
Project Manager cum Backend Engineer
Leading enterprise integration projects while designing and developing scalable backend systems. Specialized in .NET, Microservices, REST APIs, Redis, Kafka, MySQL, PostgreSQL, and cloud-native architectures.
IT Application Development Specialist
Circle K Vietnam - building backend services, middleware, internal business systems and partner integration platforms connected to POS/CMS workflows.
Backend Developer Staff
E-commerce and integration projects - API development, large data processing, database optimization and backend service delivery.
Contact
Need a backend that can survive real traffic?
Open to backend systems, integrations, automation, AI/RAG and high-impact technical problem solving.