Smart Retail POS Platform (Omnichannel POS & ERP)

Role: Backend & DevOps Engineer • Solum

Multi-tenant omnichannel POS & ERP platform operating across 200+ retail stores with real-time checkout, distributed inventory management, and automated tax e-invoicing.

// Timeline:

02/2026 — Present

// Team context:

Close collaboration with backend engineers, DevOps/SRE, frontend teams, and third-party payment & tax providers.

MODULES (SCROLL TO EXPLORE):

[CARD 01 / 07] // PROBLEM ARCHITECTURE

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Context & Problem Statement

Operating across 200+ retail stores continuously required sub-second order processing, atomic inventory decrement without race conditions, and real-time compliance with Vietnamese tax authorities via Viettel & MISA e-invoice APIs. The core challenge was guaranteeing zero event loss between the relational database and the streaming broker while maintaining automated zero-downtime GitOps rollouts.

// ENGINEERING FOCUS:

Retail Tech & Distributed ERP

// DEPLOYMENT SCOPE:

02/2026 — Present

[CARD 02 / 07] // CORE CONTRIBUTIONS

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Core Engineering Contributions

›_ Engineered core Golang microservices for payment processing, stock locking, B2B workflows, and automated per-order tax filing via Viettel/MISA APIs.
›_ Architected an asynchronous event-driven messaging layer using Azure Event Hubs (Kafka protocol) paired with the Transactional Outbox pattern.
›_ Standardized GitOps CI/CD on Kubernetes (AKS) using ArgoCD App-of-Apps, featuring automated pre-upgrade hooks running Goose DB migrations before pod rollout.
›_ Integrated receipt and document intelligence using Mistral OCR on Azure AI Foundry and a Multi-Agent automated reporting system with Azure GPT-4o.

[CARD 03 / 07] // MEASURABLE IMPACT

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Measurable Impact

✓ Sustained reliable, real-time data synchronization across 200+ active retail stores.
✓ Eliminated event loss and state drift between PostgreSQL and message queues via the Transactional Outbox pattern.
✓ Maintained p99 latency under 85ms during peak shopping periods, verified through rigorous k6 stress testing.
✓ Reduced manual deployment overhead by 85% and eliminated schema drift incidents through automated ArgoCD hooks.

[CARD 04 / 07] // SYSTEM DESIGN

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Architecture Highlights & System Design

› Transactional Outbox pattern guarantees atomic ACID persistence between PostgreSQL and Azure Event Hubs message streams.
› Redis Distributed Locking prevents race conditions when multiple cash registers sell the last stock unit concurrently.
› ArgoCD App-of-Apps with pre-upgrade lifecycle hooks ensures schema migrations succeed cleanly before new pods receive production traffic.

[CARD 05 / 07] // TECHNICAL SCOPE

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Responsibilities & Technical Scope

› Owned distributed microservices architecture and API contracts for payment, inventory, and legal e-invoicing.
› Managed cloud infrastructure as code (Terraform) on Azure and orchestrated Kubernetes workloads (AKS, k0s) with Helm.
› Configured Cloudflare edge networking (WAF, DNS), NGINX Ingress, and automated wildcard SSL renewal via cert-manager.
› Established telemetry dashboards (Grafana, Datadog) and automated daily reconciliation anomaly alerts via Slack webhook bot.

[CARD 06 / 07] // OUTCOMES & RETRO

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Delivery Outcomes & Production Impact & Lessons Learned & Engineering Takeaways

verified // Delivery Outcomes & Production Impact

✓ Achieved verified zero-downtime release deployments across the entire retail network.
✓ Automated 100% of tax e-invoicing workflows without requiring manual accountant intervention.
✓ Enabled operations engineers to detect and resolve order drift anomalies in seconds through real-time Slack alerts.

lightbulb // Lessons Learned & Engineering Takeaways

› In mission-critical retail systems, event delivery guarantees and strict concurrency controls take precedence over isolated micro-optimizations.
› Pre-upgrade database migration hooks in GitOps pipelines are essential to eliminate breaking schema drift at scale.
› Automating daily reconciliations early surfaces data mismatches before they can escalate into financial reporting incidents.

[CARD 07 / 07] // TECH SPEC & VERIFICATION

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Technology Stack

GolangPostgreSQLRedisAzure Event Hubs (Kafka)DockerKubernetes (AKS)HelmTerraformArgoCDCloudflareNGINX Ingressk6GrafanaDatadogMistral OCRAzure GPT-4o

[DOSSIER COMPLETE • SYS.01] ● 100% PRODUCTION VERIFIED

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