Engineering notes — things I keep re-explaining, written down once.
- An ADR for expired session cleanup: one cron, one public URL, one audit trail
- Bulk Welcome Email After User Import: Batch Sending, Rate Limits, and Retries
- Email and SMS Event Notifications: One Provider or Separate Vendors for US/EU Startups?
- Backend Metrics Dashboard for Cron Jobs, API Failures, Business Events, and Healthchecks
- Cron-triggered queue workers: running long background jobs past the 15-minute limit