Sĩ Nguyễn Văn

Backend-focused Software Engineer with 2+ years of production experience building CRM/ERP systems, high-concurrency distributed services. Delivered scalable multi-tenant SaaS ERP and blockchain wallet platforms serving 100K+ users for clients. Proficient in Go, Python and React with deep hands-on use of Gin, GORM, Kafka, PostgreSQL, Docker, and API Gateway.

Passionate about system deployment and operations, with a growing focus on DevOps practices. Always eager to explore and learn emerging technologies.

Fullstack Developer at ATOM Solutions JSC (2024-02 – 2026-04)

Contributed as a fullstack developer across 3 production projects, designing high-concurrency distributed services, dynamic frontend, and deploying development infrastructure across fintech, ERP/Odoo, and blockchain domains.

Fullstack Developer - Project 1: SaaS ERP Platform (Merchant Management & Sale Ecosystem) at ATOM Solutions JSC (2024-08 – 2026-04)

Contributed to the design and implementation of backend & dynamic frontend web application for Merchant Management System and Merchant Portal. Enabling flexible configuration for each customer hosting this platform.

• Contributed to the design and implementation of backend & dynamic frontend web application for Merchant Management System and Merchant Portal. Enabling flexible configuration for each customer hosting this platform.
• Implemented multi-tenant architecture and SaaS model.
• Integrated with BVBank Digistore Open APIs for merchant onboarding, payment processing.
• Built POS management service to provision and activate POS machines for merchants.
• Built payment integration service for Virtual Account management and QR code generation.
• Built a webhook to process callback from BVBank Digistore, and developed a background worker to handle IPN for Card & QR transactions and notify real-time payment completion.
• Customized Odoo 18 modules including Inventory, Sale, Accounting, Point of Sale, Discount & Loyalty.
• Developed an e-invoice module integration with M-Invoice provider.
• Implemented centralized authentication using APISIX API Gateway across all services.
• Extended Keycloak using custom Java SPIs for Single Sign On.
• Deployed development infrastructure including Postgres, Kafka, APISIX, Keycloak, EMQX on Docker, Nginx with Cloudflare domain mapping.
• Leveraged Openclaw, Ollama, and Codex Tool to implement an AI-workflow for analyzing BRD docs and implementing minimum features.

Fullstack Developer - Project 2: Blockchain Wallet Application at ATOM Solutions JSC (2025-01 – 2026-02)

Designed and built 4 Golang microservices using Clean Architecture, event-driven design with Kafka, supporting 100K+ users on Solana and EVM chains.

• Designed and built 4 Golang microservices using Clean Architecture, event-driven design with Kafka, supporting 100K+ users on Solana and EVM chains.
• Developed a secure service to handle wallet key access with high security, deployed on AWS Nitro Enclaves.
• Applied event-driven design and concurrency for wallet creation, recovery, handling transactions, token transfers, coin swaps.
• Developed real-time alerts via WebSocket and notification email via AWS SES.
• Built a scanner service with concurrency to monitor transaction on-chain and update status.
• Implemented RSA to encrypt Kafka messages with a public key and decrypt with a private key to secure messages.
• Deployed proxy functions on AWS Lambda using AWS API Gateway & Cognito authentication to secure third-party API keys in AWS Secrets Manager.
• Worked with DevOps on AWS to set up API Gateway and deploy Lambda functions.

Fullstack Developer - Project 3: Online Booking Platform at ATOM Solutions JSC (2024-02 – 2024-11)

Built bus ticketing and hotel booking platform integrating Vexere Open APIs.

• Built bus ticketing and hotel booking platform integrating Vexere Open APIs.
• Designed and built Admin Panel for order, voucher, user, and config management.
• Implemented race-condition-safe voucher redemption using PostgreSQL row-level locking.
• Integrated Elasticsearch to optimize booking search and retrieval performance.

Software Engineering in Software Engineering – FPT College (2024-01 – 2024-01)