Email Deliverability Checker
Diagnose email deliverability issues by checking SPF, DKIM, DMARC, and other DNS records - fix why your emails land in spam.
When to Use This Skill
- •Delivery troubleshooting - Emails landing in spam
- •New domain setup - Configure email authentication
- •Migration audit - Verify email config after domain change
- •Client onboarding - Check client email health
- •Compliance check - Ensure proper authentication
What Claude Does vs What You Decide
| Claude Does | You Decide |
|---|---|
| Structures analysis frameworks | Metric definitions |
| Identifies patterns in data | Business interpretation |
| Creates visualization templates | Dashboard design |
| Suggests optimization areas | Action priorities |
| Calculates statistical measures | Decision thresholds |
Dependencies
bash
pip install dnspython click
Commands
Full Audit
bash
python scripts/main.py audit example.com python scripts/main.py audit example.com --output report.html
Check SPF
bash
python scripts/main.py spf example.com
Check DKIM
bash
python scripts/main.py dkim example.com --selector google python scripts/main.py dkim example.com --selector default
Check DMARC
bash
python scripts/main.py dmarc example.com
Check MX Records
bash
python scripts/main.py mx example.com
Examples
Example 1: Full Email Audit
bash
python scripts/main.py audit acme-corp.com # Output: # Email Deliverability Audit: acme-corp.com # ────────────────────────────────────────── # MX Records: ✓ Found (Google Workspace) # SPF: ✓ Valid # DKIM (google): ✓ Valid # DMARC: ✗ Missing (CRITICAL) # # Score: 75/100 # # Issues Found: # 1. [CRITICAL] No DMARC record found # Fix: Add TXT record for _dmarc.acme-corp.com # Value: v=DMARC1; p=none; rua=mailto:dmarc@acme-corp.com
Example 2: Diagnose SPF Issues
bash
python scripts/main.py spf newsletter-sender.com # Output: # SPF Analysis: newsletter-sender.com # ──────────────────────────────────── # Record: v=spf1 include:_spf.google.com include:sendgrid.net ~all # # Status: ✓ Valid # # Authorized Senders: # - Google Workspace (include:_spf.google.com) # - SendGrid (include:sendgrid.net) # # Policy: ~all (soft fail) # Warning: Consider changing to -all (hard fail) for better security
Email Authentication Records
| Record | Purpose | Location |
|---|---|---|
| SPF | Authorize sending servers | TXT on root domain |
| DKIM | Cryptographic signature | TXT on selector._domainkey |
| DMARC | Policy and reporting | TXT on _dmarc subdomain |
| MX | Mail delivery servers | MX on root domain |
Common SPF Includes
| Provider | SPF Include |
|---|---|
| Google Workspace | include:_spf.google.com |
| Microsoft 365 | include:spf.protection.outlook.com |
| SendGrid | include:sendgrid.net |
| Mailchimp | include:servers.mcsv.net |
| Amazon SES | include:amazonses.com |
DKIM Selectors by Provider
| Provider | Common Selector |
|---|---|
| Google Workspace | google |
| Microsoft 365 | selector1, selector2 |
| SendGrid | s1, s2 |
| Mailchimp | k1 |
Deliverability Score Factors
| Factor | Weight | Impact |
|---|---|---|
| Valid MX | 20% | Can't receive replies |
| Valid SPF | 25% | Server authorization |
| Valid DKIM | 25% | Message integrity |
| Valid DMARC | 30% | Policy enforcement |
Skill Boundaries
What This Skill Does Well
- •Structuring data analysis
- •Identifying patterns and trends
- •Creating visualization frameworks
- •Calculating statistical measures
What This Skill Cannot Do
- •Access your actual data
- •Replace statistical expertise
- •Make business decisions
- •Guarantee prediction accuracy
Related Skills
- •dns-audit - Full DNS health check
Skill Metadata
- •Mode: centaur
yaml
category: email-tools subcategory: deliverability dependencies: [dnspython] difficulty: beginner time_saved: 2+ hours/week