> ## Documentation Index
> Fetch the complete documentation index at: https://internal.softcrum.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Runbook — Email Deliverability & Domain Setup

> 1. Tenant sender domain: create in Resend; give tenant SPF/DKIM DNS records from console; verify; until verified, sends use shared subdomain (default tier per DEC-F4). 2.

1. **Tenant sender domain:** create in Resend; give tenant SPF/DKIM DNS records from console; verify; until verified, sends use shared subdomain (default tier per DEC-F4).
2. **Warm-up (new dedicated domain):** wk1 ≤200/day → wk2 ≤1k → wk3 ≤5k → wk4 normal; transactional first, marketing last; monitor bounce \<2%, complaint \<0.1%; abort warm-up if exceeded.
3. **Status ingestion:** Resend webhooks → send\_status\_history; hard bounce/complaint ⇒ suppressions (automatic — verify daily job green).
4. **Provider limits:** current global token bucket settings documented here; BEFORE G1: request Resend rate raise (ticket link), load-test rails in cert (k6 profile `blast-vs-otp`), record measured ceiling.
5. **Incident: transactional latency spike:** check transactional queue depth → confirm marketing yield engaged → if provider 429s: verify buckets, reduce marketing tokens, page on-call.