Mera — Order → Inventory → Courier

Mera — Order → Inventory → Courier A sequence diagram generated by Archify. place Order POST /orders verify JWT + policy claims ok read Inventory miss SELECT inventory (fallback) rows reserve Inventory INSERT Shipment emit job-fulfillment ship via adapter ack + tracking 200 Order + Shipment render Capture Verify inventory Fulfill Customer · browser · Sequence participant Customer browser Web App · Mera Astro · Sequence participant Web App Mera Astro Mera API · domain commands · Sequence participant Mera API domain commands Auth · JWT + RBAC/ABAC · Sequence participant Auth JWT + RBAC/ABAC Redis · cache / queue · Sequence participant Redis cache / queue PostgreSQL · canonical · Sequence participant PostgreSQL canonical Shiprocket · courier adapter · Sequence participant Shiprocket courier adapter Trace · event bus · Sequence participant Trace event bus Legend request return security async trace default message

Canonical state

  • • Order → Inventory → Shipment are canonical writes to PostgreSQL
  • • Redis is read-through cache and queue, never the source of truth
  • • Every write emits an event for agents and Trace

Failure + retry

  • • Cache miss → PostgreSQL fallback → warm cache
  • • Insufficient inventory → event-stockout, no oversell
  • • Courier fail → retry with alternate courier

Trace-ready

  • • Each message has a stable ID for Trace UI: RTO% → Orders → COD → Pincode → Courier → Shipment → Return
  • • Auth check is security-colored and precedes any data read
  • • Return messages are quieter than forward calls