Issue: Investigate Billing Service operational risk 02

ID: GH-3002 Date: 2026-01-19 Repository: acme-commerce/billing-service Service: Billing Service Owner: Revenue Platform Status: open Type: issue

Summary

This issue tracks production-readiness work for the Billing Service. The concern is related to out-of-order event delivery from the shared event bus. The implementation area touches API contracts API-BILLING-01, API-BILLING-02, service telemetry, and operational runbooks.

Engineering Notes

• Validate that retries are bounded and idempotency keys are respected.
• Add structured logs with service, correlation_id, and customer_impact fields.
• Confirm dashboards show p95 latency, error rate, dependency saturation, and queue depth.
• Cross-service impact should be reviewed with Checkout Service, Billing Service, Inventory Service, Authentication Service, and Notification Service owners when applicable.

Acceptance Criteria

1. Contract tests cover expected and malformed payloads.
2. Runbook references are updated for Billing Service.
3. The change can be linked from Jira remediation tickets and incident reviews.