Orders Microservice: Multi-Channel Fulfillment

Overview

A production orders microservice powering multi-channel e-commerce fulfillment at Yalidine Delivery. Merchant orders arrive through HMAC-validated webhooks from Shopify, WooCommerce, and Google Sheets, flow through an API gateway into the orders service, and are executed by a fulfillment orchestrator that reconciles stock and records failures. Built as a NestJS 11 monorepo with RabbitMQ messaging, Redis caching, and PostgreSQL persistence.

What I Did

• →Architected a NestJS 11 monorepo: API gateway, orders service, fulfillment orchestrator, and shared libraries (common enums, interfaces, and a reusable microservice client module)
• →Built the API gateway handling routing, authentication, and rate limiting for all inbound traffic
• →Implemented the orders service owning the full order lifecycle, tracking codes, and draft reasons
• →Built HMAC-validated webhook ingestion for Shopify, WooCommerce, and Google Sheets order sources
• →Designed the fulfillment orchestrator with lifecycle hooks, snapshot/delta diffing, stock reconciliation, and failure recording
• →Set up RabbitMQ RPC messaging between services with per-client timeouts to isolate slow consumers
• →Used Redis for caching and session state to keep hot paths off the database
• →Modeled orders and fulfillment plans in PostgreSQL

Challenges

• •Keeping stock consistent while orders arrive concurrently from three external platforms
• •Processing webhooks idempotently so retries from Shopify/WooCommerce never duplicate orders
• •Diffing order snapshots against deltas to compute the minimal fulfillment work on each update
• •Recording and surfacing fulfillment failures without blocking the ingestion pipeline

Results

• ✓Single source of truth for orders across three sales channels
• ✓Snapshot/delta diffing avoids reprocessing entire orders on every merchant update
• ✓HMAC validation and gateway rate limiting protect the pipeline from spoofed or abusive traffic
• ✓Shared microservice client module standardized inter-service communication across the monorepo