Email Deliverability Debugger

Overview

This skill systematically diagnoses why emails fail to reach inboxes by checking the entire delivery chain: DNS authentication (SPF, DKIM, DMARC), sending IP reputation, email content, headers, and provider-specific configuration. It produces actionable fixes ranked by impact.

Instructions

Step 1: Check DNS Authentication Records

# SPF record
dig +short TXT example.com | grep "v=spf1"

# DKIM (check common selectors)
for sel in s1 s2 k1 google default sendgrid; do
  dig +short TXT ${sel}._domainkey.example.com
done