Warehouse Picker Routing: GraphHopper, OR-Tools & C++

Warehouse Picker Routing Optimization (GraphHopper & OR-Tools) Answer-first: Minimizing walking distance for warehouse pickers requires solving the Traveling Salesperson Problem (TSP) inside a physical building. The 2026 standard architecture uses a Java-based Indoor GraphHopper instance to generate a 100x100 Distance Matrix from custom OpenStreetMap (OSM) data, which is then fed into a C++ Google OR-Tools gRPC Microservice to calculate the absolute optimal pick sequence in under 15 milliseconds. The S-Shape Trap in Warehouse Picking In legacy Warehouse Management Systems (WMS), workers are directed to pick items using heuristic patterns like the S-Shape (Z-pattern) or Largest Gap. These heuristics force the worker to walk down every aisle that contains an item, traversing the aisle from end to end. ...

August 1, 2026 · 5 min · Lê Tuấn Anh

Order Splitting Algorithm: Graph Coloring & OPA in Golang

Order Splitting at Scale: Graph Coloring, Bin Packing, and OPA in Go Answer-first: Real-time e-commerce order splitting is a Constraint Satisfaction Problem (CSP). To determine the absolute minimum number of cardboard boxes required for a complex cart without violating safety rules or physical dimensions, the 2026 standard pipeline relies on Open Policy Agent (OPA) for dynamic business rules, Golang (gonum) for Graph Coloring (Welsh-Powell) to resolve logical conflicts, and First-Fit Decreasing Bin Packing to resolve physical constraints. This pipeline executes in under 50ms during synchronous checkout, deferring heavy Multi-Warehouse routing to async workers. ...

August 1, 2026 · 5 min · Lê Tuấn Anh

Blueprint: E-commerce Microservices Architecture with Golang

Ecommerce Microservices Architecture Diagram: 21-Service Blueprint E-Commerce Architecture Patterns: Monolith vs Microservices Answer-first: An ecommerce microservices architecture diagram organizes system capabilities into 6 core bounded domains (Commerce Flow, Product & Content, Logistics, Post-Purchase, Identity & Access, Platform Operations), connecting 21 Golang microservices via gRPC and Dapr Pub/Sub event mesh for high-concurrency scalability. Monolithic vs Microservices E-Commerce Comparison Dimension Monolithic E-Commerce Microservices E-Commerce Scaling Vertical scaling of entire monolith application Independent horizontal scaling per domain (e.g., Catalog 10x Cart) Database Architecture Single shared database with cross-table SQL joins Database-per-service (PostgreSQL, Redis, Elasticsearch) with zero cross-domain access Deployment Frequency Low frequency; all-or-nothing monolithic releases High frequency; independent CI/CD pipelines per microservice Fault Tolerance Low; a single bug or memory leak crashes the entire store High; failure in one domain (e.g., Reviews) does not block Checkout Complexity Low initial architectural and operational complexity High distributed complexity (Saga pattern, gRPC contracts, Dapr mesh) Operational Cost Lower initial cost; scales expensively at high traffic Higher initial infrastructure setup; cost-effective at high scale Practical latency and memory metrics comparing an Envoy-based API Gateway to a custom Go reverse proxy under 100k concurrent connections. How to tune circuit breaker thresholds (go-resiliency/breaker) to prevent premature service isolation during temporary network jitters. When transitioning from a monolithic platform to a distributed microservice setup, the hardest question isn’t “How do we write the code?” — it’s “How do these moving parts talk to each other safely, and why is each boundary drawn exactly where it is?” ...

April 12, 2026 · 10 min · Lê Tuấn Anh