Email deliverability optimization skill used by the Editor-in-Chief and analyst agents. Provides spam filter avoidance, technical authentication, content filtering rules, and list hygiene management methodologies. Use for 'deliverability,' 'spam filters,' 'email authentication,' 'send optimization,' and similar requests.
Technical deliverability expertise used by the editor-in-chief and analyst agents when designing final edits and send strategies.
No matter how perfect your newsletter is, if it doesn't reach the inbox, all effort is wasted. On average, 15–20% of emails land in spam folders or promotional tabs.
| Risk Level | Word/Pattern | Alternative |
|---|---|---|
| High | Free, FREE, 100% off, Winner | "Complimentary," "Gift," "Special offer" |
| High | !!!, ???, ALL CAPS |
| One exclamation max, sentence case |
| Medium | Act now, Urgent, Deadline | "By this week," "Limited time" |
| Medium | Click here, Click now | "Check it out," "Take a look" |
| Low | Re:, Fwd: (fake reply/forward) | Absolutely prohibited — destroys trust |
| Factor | Optimal State | Management Method |
|---|---|---|
| Bounce Rate | Below 2% | Remove hard bounces immediately, soft bounces after 3 |
| Spam Complaint Rate | Below 0.01% | Maintain content quality, make unsubscribing easy |
| Authentication | SPF + DKIM + DMARC configured | Coordinate with domain administrator |
| Dedicated IP | When sending 100K+/month | Shared IPs are affected by others' reputation |
| IP Warm-up | Gradual increase over 2–4 weeks for new IPs | Day 1: 50 emails → double daily → target volume |
Rendering issues that must be verified during newsletter editing:
| Client | Considerations |
|---|---|
| Gmail | Prevent Promotions tab classification — reduce images, increase text, use personal tone |
| Outlook | Limited CSS support — avoid complex layouts, use table-based layouts |
| Apple Mail | Dark mode support — use transparent background images, test color inversion |
| All Mobile | Single-column layout, buttons minimum 44x44px, font 14px+ |
Legal requirements that must be verified when publishing a newsletter:
| # | Item | Check |
|---|---|---|
| 1 | No spam trigger words in subject line | [ ] |
| 2 | Preheader text configured | [ ] |
| 3 | All links verified working | [ ] |
| 4 | Image alt text entered | [ ] |
| 5 | Mobile rendering tested | [ ] |
| 6 | Unsubscribe link working | [ ] |
| 7 | Sender information accurate | [ ] |
| 8 | A/B test setup confirmed | [ ] |
| 9 | Send time optimized per segment | [ ] |
| 10 | Test send → receipt confirmed | [ ] |