Email marketing

Skill Mattakushi432/Claude-Code-Skills-Custom-DevTools-Pack/plugins/devtools-pack/skills/email-marketing

A curated pack of custom Claude Code skills for developers — installable as a Claude Code plugin marketplace.

Install

npx -y skills add Mattakushi432/Claude-Code-Skills-Custom-DevTools-Pack --skill email-marketing

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When to activate: email sequences, email campaigns, subject lines, drip campaigns, email automation, deliverability, segmentation, re-engagement

SKILL.md

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Email Marketing

Subject Line Formulas

High-Converting Patterns

Formula	Example
Number + Benefit	"7 ways to cut churn by 40%"
Question (pain)	"Still losing leads at checkout?"
Curiosity gap	"We found something weird in your data"
Social proof	"How [Company] grew to 10k users in 90 days"
Urgency + Scarcity	"Last 24 hours: 40% off ends tonight"
Personalization	"[Name], your account needs attention"
Controversy	"Cold outreach is dead (here's what works)"

Rules

30-50 characters for mobile preview
Avoid spam triggers: FREE, !!!, ALL CAPS, "guaranteed"
A/B test subject lines on 20% of list before full send
Preview text (preheader) should complement, not repeat subject

Email Sequence Architecture

Welcome Series (Days 0-7)

Day 0:  Welcome + what to expect (immediate)
Day 1:  Your #1 quick win (value delivery)
Day 3:  Social proof + case study
Day 5:  Core product/service education
Day 7:  Soft CTA → next step or upgrade

Onboarding Series (SaaS)

Day 0:  Account created — setup checklist
Day 1:  Did you complete Step 1? (triggered)
Day 3:  Feature spotlight #1 + video walkthrough
Day 5:  Success story from similar user
Day 7:  "Are you stuck?" offer help
Day 14: Usage check — power users vs inactive
Day 21: Case study + upsell to higher tier

Nurture Series (Lead → Customer)

Email 1: Educational content (no pitch)
Email 2: Problem agitation + framework
Email 3: Case study (prove it works)
Email 4: FAQ / objection handling
Email 5: Soft offer + trial/demo CTA
Email 6: Hard offer + urgency/deadline
Email 7: Last chance + scarcity

Re-engagement Series

Email 1: "We miss you" — simple, personal tone
Email 2: Best content they missed
Email 3: Survey — what can we do better?
Email 4: Final offer — exclusive discount
Email 5: "This is goodbye" + unsubscribe confirmation

Rule: Sunset unengaged subscribers after 90 days inactivity.

Segmentation Strategy

Behavioral Segments

Segment	Criteria	Message
New subscribers	<7 days	Welcome series
Engaged	Opened in last 30d	New features, upsells
At-risk	No opens in 60-90d	Re-engagement
Churned	No opens in 90d+	Win-back or sunset
Customers	Purchase tag	Onboarding, upsell
High LTV	Top 20% spend	VIP treatment
Trial users	In trial	Conversion sequence

Demographic Segments

Industry vertical → relevant case studies
Company size → SMB vs Enterprise messaging
Role (founder vs marketer vs developer) → feature emphasis
Geography → timezone send optimization, local events

Engagement Score Formula

Score = (Opens × 1) + (Clicks × 3) + (Purchases × 10) - (Days since last activity × 0.1)

Deliverability

Technical Setup (Required)

SPF record: v=spf1 include:sendgrid.net ~all
DKIM: 2048-bit key, verified in DNS
DMARC: v=DMARC1; p=quarantine; rua=mailto:[email protected]
Custom sending domain (not shared IP for >10k sends/mo)
Dedicated IP (when list >50k and sending consistently)

List Health

Double opt-in for new subscribers (improves quality 2-3x)
Remove hard bounces immediately
Remove soft bounce addresses after 3 bounces
Suppress unsubscribes within 10 business days (CAN-SPAM)
Run list through validation service quarterly (ZeroBounce, NeverBounce)

Sender Reputation Rules

Maintain open rate > 20%
Keep spam complaint rate < 0.08% (Google/Yahoo threshold)
Warm up new IPs: start at 500/day, double weekly
Send to most engaged first when warming

Inbox Placement Testing

Tools: GlockApps, Mail-Tester, Litmus Spam Testing Test before sends over 10k: check spam score, inbox vs promo vs spam folder

A/B Testing Framework

What to Test (Priority Order)

Subject line (biggest impact)
From name / sender
Send time / day
CTA button text and color
Email length (short vs long)
Plain text vs HTML
Personalization tokens

Test Methodology

Minimum sample size: 1,000 per variant (500 minimum if small list)
Test ONE variable at a time
Statistical significance: 95%+ confidence
Run for minimum 4 hours before declaring winner
Document results in testing log

Split Test Calculator

Required sample = (Z² × p × (1-p)) / E²
where Z=1.96 (95% confidence), p=baseline rate, E=minimum detectable effect

Email Metrics & Benchmarks

Metric	Good	Great	How to improve
Open rate	20-25%	35%+	Subject line, sender name, list quality
Click rate	2-3%	5%+	CTA clarity, content relevance
Click-to-open	10-15%	20%+	Email body copy, offer strength
Unsubscribe rate	<0.5%	<0.2%	Segmentation, frequency
Spam complaints	<0.08%	<0.02%	Relevance, easy unsubscribe
Conversion rate	1-2%	5%+	Offer + landing page alignment

Email Copywriting Template

Structure

[Subject: Pattern from formulas above]
[Preheader: Complement, don't repeat subject]

[Opening hook: 1-2 sentences — problem or curiosity]

[Body: Short paragraphs, max 3 sentences each]
  - Line 1: Problem/context
  - Line 2-3: Solution/value
  - Line 4-5: Proof/specifics

[CTA: Single, clear button]
  "Get [specific thing] →"

[P.S.: Second most-read element — restate offer or add urgency]

Plain Text Best Practices

Use plain text for personal/conversational emails
HTML for promotional/newsletter-style
Include plain text version of all HTML emails

Automation Triggers

Behavioral Triggers

Trigger	Delay	Email
Sign up	Immediate	Welcome
First login	+1 day	Getting started
Feature activated	Immediate	Tips for feature
Inactive 7 days	+7 days	Check-in
Abandoned cart	+1 hour	Cart reminder
Purchase	Immediate	Receipt + onboarding
Trial expires -3 days	-72h	Upgrade nudge
Trial expired	Day 0	Final offer

Compliance Checklist

Unsubscribe link in every email (CAN-SPAM, CASL, GDPR)
Physical mailing address in footer
Clear sender identification
Honor unsubscribes within 10 days (CAN-SPAM) / immediately (GDPR)
Do not use deceptive subject lines
GDPR: lawful basis documented (consent or legitimate interest)
CASL: explicit/implied consent recorded with timestamp

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