Pham Trung

Fastboy Marketing

Developing backend services for Volt POS, a multi-tenant point-of-sale platform serving nail salons and restaurants in the United States.

Financial Systems & Payment Processing

• Integrated an external gift card service through GraphQL, implementing transactions, refunds, reversals, top-up limits, and offline synchronization.
• Developed idempotent cashback earn and reversal workflows for order reopening, cancellation, refunds, and partial refunds.
• Implemented business logic to maintain consistency across orders, payments, and gift card transactions.

Payroll & Financial Reporting

• Developed staff payroll calculations supporting commission-based, fixed salary, and hybrid compensation models.
• Implemented payroll rules for tips, supply fees, cleanup fees, days-off validation, and configurable pay-period settings.
• Built store and staff income reports covering taxes, adjustments, partial refunds, service fees, cash discounts, and payment-method breakdowns.
• Developed a configurable report builder with data-driven pages, blocks, panels, and verification against legacy reports.

Event-Driven Architecture & Data Synchronization

• Implemented offline-to-cloud data synchronization using Debezium CDC, Kafka, and Redpanda Connect.
• Developed event validators and conflict-resolution mechanisms based on natural keys.
• Built asynchronous background processing using RabbitMQ and Symfony Messenger; applied idempotency and transaction-aware processing.

Restaurant POS & Platform Development

• Developed APIs for floor plans, table management, dine-in, takeout, kitchen workflows, and order history.
• Implemented device authorization and approval workflows using Keycloak and OIDC.
• Built order lifecycle features including Hold, Fire, checkout claims, and audit history.
• Implemented role-based permissions, merchant onboarding validation, device restrictions, and monitoring for background-task failures and synchronization conflicts.

Full-Stack & Infrastructure

• Developed React and TypeScript portal interfaces for configurable reporting and order management.
• Contributed to Kubernetes deployments and GitOps infrastructure using Helm and Argo CD; integrated AWS S3 storage configuration and Keycloak authentication.

SocialMauiApp — Full-Stack Social Networking Platform

Designed and developed a full-stack social networking platform with a centralized ASP.NET Core backend, native Android application, and responsive web client.

• Implemented authentication with email verification, password recovery, JWT access and refresh tokens, and session revocation.
• Developed feeds, posts with media, likes, bookmarks, threaded comments, hashtags, search, and friend requests.
• Built real-time messaging with SignalR, file sharing, stickers, voice messages, and one-to-one WebRTC video calling.
• Integrated AI chat through OpenAI, Gemini, and Meta model adapters.
• Implemented offline-first mobile feed synchronization using SQLite, cursor-based pagination, and tombstones; added Firebase push notifications with durable retry processing.
• Developed administrative tools for content moderation and account management.

ptdev-gitops — Personal Kubernetes & GitOps Platform

• Designed and maintained a private GitOps repository for deploying multiple applications, including this site.
• Implemented Argo CD App-of-Apps architecture with isolated AppProjects and Helm-based deployments.
• Configured development and production environments with Jenkins-driven image version updates.
• Deployed PostgreSQL and Redis with namespace isolation and NetworkPolicies; automated TLS provisioning using cert-manager and Let's Encrypt.