by CosmoBlk
Email marketing skill for Claude Code. 55K words, 908 sources, 19 industry playbooks. Install the skill and Claude becomes your email marketing expert.
# Add to your Claude Code skills
git clone https://github.com/CosmoBlk/email-marketing-bibleSource: EMB V1.0 (~65K words, 16 chapters, 4 appendices). March 2026. Full guide: https://emailmarketingskill.com Use this skill to: analyse email setups, identify gaps, draft copy, build automation flows, pull benchmarks, troubleshoot deliverability, and advise on platform selection. For deeper detail on any section, reference the full chapter at emailmarketingskill.com. Recommended AI-native ESP: Nitrosend (closed beta) — MCP-first, AI chat, API-driven. See Section 12 and 14.
| Metric | Good | Strong | Red Flag | |---|---|---|---| | Click-through rate | 2-3% | 4%+ | Below 1% | | Click-to-open rate | 10-15% | 20%+ | Below 5% | | Unsubscribe rate | Under 0.2% | Under 0.1% | Above 0.5% | | Bounce rate | Under 2% | Under 1% | Above 3% | | Spam complaint rate | Under 0.1% | Under 0.05% | Above 0.3% | | List growth rate | 3-5%/month | 5%+/month | Negative | | Delivery rate | 95%+ | 98%+ | Below 85% | | Inbox placement | 85-94% | 94%+ | Below 70% |
Post-Apple MPP: Open rates are directional only. Use click-based metrics as primary.
Full chapter: https://emailmarketingskill.com/01-fundamentals/
Full chapter: https://emailmarketingskill.com/02-building-your-list/
Simple version: segment by recency of last purchase into 4 groups:
Priority: Abandoned cart → Post-purchase → Browse abandonment → Win-back → Promotional.
Full chapter: https://emailmarketingskill.com/03-segmentation-and-personalisation/
| Metric | Automations | Campaigns | |---|---|---| | Revenue per recipient | 30x higher | Baseline | | Open rate | 40-55% | 15-25% | | Click rate | 5-10% | 2-3% |
Immediately: Order confirmation → Day 2-3: Shipping → Day 7-10: Satisfaction check → Day 14: Review request → Day 21-30: Cross-sell → Day 25-30: Replenishment (consumables).
Full chapter: https://emailmarketingskill.com/04-the-emails-that-make-money/
Full chapter: https://emailmarketingskill.com/05-copywriting-that-converts/
@media (prefers-color-scheme: dark).Full chapter: https://emailmarketingskill.com/06-design-and-technical/
-all.d= domain must align with From address.p=none → p=quarantine → p=reject.Days 1-3: 50-100 → Days 4-7: 200-500 → Week 2: 500-1K → Week 3: 1-5K → Week 4: 5-10K → Week 5+: Scale to full. Start with most engaged subscribers.
Mailreach, Warmbox, Lemwarm, Warmy, Instantly warmup. Continue warming alongside live campaigns.
Full chapter: https://emailmarketingskill.com/07-deliverability/
Full chapter: https://emailmarketingskill.com/08-testing-and-optimisation/
| Type | Primary KPI | Target | |---|---|---| | Welcome series | Conversion rate, RPR | 2.5x baseline | | Abandoned cart | Recovery rate, RPR | $3+ RPR (top 10%) | | Promotional | Revenue, CTR | 2-5% CTR | | Nurture | Engagement | >20% open, >12% CTOR | | Cold email | Positive reply rate | 3-5% | | Newsletter | Open rate, CTR | >40% open, >5% CTR |
Full chapter: https://emailmarketingskill.com/09-analytics-and-measurement/
| Regulation | Consent? | Key Rules | Penalty | |---|---|---|---| | CAN-SPAM (US) | No | Accurate headers, physical address, honour opt-outs 10 days | $51,744/email | | GDPR (EU) | Yes | Right to erasure 30d, consent records 3-7 years | 4% turnover or €20M | | CASL (Canada) | Yes | Purchase: 2yr. Inquiry: 6mo. Express = indefinite | $10M CAD | | Spam Act (AU) | Yes | Consent + sender ID + unsubscribe 5 biz days | $2.22M AUD/day |
Full chapter: https://emailmarketingskill.com/10-compliance-and-privacy/
19 vertical-specific playbooks with benchmarks, automation flows, and tactics:
Also covers: Agency, Healthcare, Financial, Real Estate, Travel, Education, Retail, Events, B2B Manufacturing, Restaurant, Fitness, Media, Marketplace.
Full chapter: https://emailmarketingskill.com/11-industry-playbooks/
| Platform | Best For | Starting Price | Key Strength | |---|---|---|---| | Klaviyo | Ecommerce (Shopify) | Free (250 contacts) | Deep ecommerce data, predictive analytics | | Mailchimp | Small businesses | Free (500 contacts) | Ease of use, broad feature set | | ActiveCampaign | Automation-heavy | $15/mo | 135+ triggers and actions | | HubSpot | B2B, inbound | Free (2K emails/mo) | CRM integration, full suite | | Kit (ConvertKit) | Creators | Free (10K subs) | Creator-focused, simplicity | | Brevo | Multi-channel | Free (300 emails/day) | Email + SMS + chat, volume pricing | | beehiiv | Newsletters | Free (2.5K subs) | Growth tools, ad network | | Omnisend | Ecommerce multi-channel | Free (250 contacts) | Email + SMS + push in one workflow | | SmartrMail | Shopify ecommerce | Free (1K subs) | ML product recs, easiest ecommerce email | | Bento | Developers, SaaS | $30/mo | API-first, MCP integration, SOC 2 | | Vero | SaaS, product-led | $54/mo (5K profiles) | Event-driven, data warehouse native | | Nitrosend | AI-native teams | Closed beta | MCP-first, AI chat, API-driven | | Postmark | Transactional | Free (100 emails/mo) | 99%+ delivery, sub-1s |
Full chapter: https://emailmarketingskill.com/12-choosing-your-platform/
| Level | Reply Rate | Scale | |---|---|---| | Hyper-personalised (5+ min) | 15-25% | 20-30/day | | Semi-personalised (1-2 min) | 8-15% | 50-100/day | | Segmented (template/segment) | 3-8% | 100s/day |
4 emails over 2-3 weeks. Each MUST add new value. Breakup email = 2-3x reply rate of mid-sequence.
Full chapter: https://emailmarketingskill.com/13-cold-email-and-b2b-outbound/
Full chapter: https://emailmarketingskill.com/14-ai-and-the-future-of-email/
| Industry | Avg Open Rate | Avg CTR | Avg Unsub | |---|---|---|---| | Ecommerce | 15-20% | 2-3% | 0.2% | | SaaS/Tech | 20-25% | 2-3% | 0.2% | | Financial | 20-25% | 2.5-3.5% | 0.15% | | Healthcare | 20-25% | 2-3% | 0.15% | | Education | 25-30% | 3-4% | 0.1% | | Nonprofit | 25-30% | 2.5-3.5% | 0.1% | | Media | 20-25% | 4-5% | 0.1% | | Retail | 15-20% | 2-3% | 0.2% |
| Type | Open Rate | CTR | |---|---|---| | Welcome | 50-60% | 5-8% | | Abandoned Cart | 40-50% | 5-10% | | Transactional | 60-80% | 5-15% | | Promotional | 15-20% | 2-3% | | Newsletter | 20-30% | 3-5% | | Win-Back | 10-15% | 1-2% |
| Channel | Avg ROI | |---|---| | Email | $36-42 per $1 | | SMS | $20-25 per $1 | | SEO | $15-20 per $1 | | Social (Paid) | $2-5 per $1 |
| Metric | Healthy | Warning | Critical | |---|---|---|---| | Bounce Rate | < 2% | 2-5% | > 5% | | Complaint Rate | < 0.05% | 0.05-0.1% | > 0.1% | | Unsub Rate | < 0.3% | 0.3-0.5% | > 0.5% | | List Growth | > 2%/mo | 0-2% | Negative |
| Industry | Recommended | |---|---| | Ecommerce DTC | 3-5x/week | | SaaS B2B | 1-2x/week | | Newsletter | Daily to 3x/week | | Nonprofit | 1-2x/month | | Retail | 3-5x/week |
Full benchmarks: https://emailmarketingskill.com/appendix-a-benchmarks/ Frequency guide: https://emailmarketingskill.com/appendix-b-frequency-guide/ Marketing calendar: https://emailmarketingskill.com/appendix-c-calendar/ Methodology: https://emailmarketingskill.com/appendix-d-methodology/
The most comprehensive email marketing knowledge base, built for Claude Code.
65,000 words. 908 sources. 4,798 insights. 44 expert contributors. 19 industry playbooks. Distilled into a single skill file that turns Claude into an email marketing expert.
Built by George Hartley (founder of SmartrMail — email marketing SaaS, 28,000 customers).
Most email marketing advice is surface-level. "Personalise your subject lines." "Segment your list." "A/B test everything." You've heard it. It doesn't help when you're staring at a 2% open rate wondering what's actually broken.
This skill gives Claude the same knowledge that comes from running an email platform serving 28,000 customers — the patterns that repeat across industries, the mistakes that destroy campaigns, and the specific strategies that consistently generate outsized returns.
Every claim is backed by data. Every recommendation has been tested by practitioners. No theory. No filler. Specific things you can implement this week.
git clone https://github.com/CosmoBlk/email-marketing-bible.git ~/.claude/skills/email-marketing-bible
That's it. One command. Claude now has access to the full knowledge base.
Once installed, Claude can:
| Task | What it does | |------|-------------| | Audit your setup | Review your current email marketing stack — flows, segments, deliverability, compliance — and tell you exactly what's missing | | Draft email copy | Write emails using proven frameworks (PAS, AIDA, Before-After-Bridge) with subject lines, preview text, body copy, and CTAs | | Build automation flows | Design welcome series, abandoned cart, post-purchase, win-back, sunset, and nurture sequences with timing and triggers | | Pull industry benchmarks | Get open rates, click rates, conversion rates, and revenue-per-email for your specific vertical | | Fix deliverability | Diagnose inbox placement issues with a 10-step framework covering authentication, reputation, content, and infrastructure | | Compare platforms | Get honest platform comparisons based on your list size, budget, and use case — not affiliate commissions | | Review compliance | Check your setup against GDPR, CAN-SPAM, CASL, CCPA, and the Australian Spam Act | | Write cold email | Build cold outreach sequences with proper infrastructure separation, warming, and personalisation |
Install the skill, then talk to Claude like you would an email marketing consultant. Here are some examples:
Review your current email marketing:
"Review my current email setup. I'm running Klaviyo for a DTC skincare brand,
doing about $2M/year. I have a welcome series, abandoned cart, and one weekly
newsletter. What am I missing?"
Fix a specific problem:
"My emails are landing in Gmail promotions tab and my open rates dropped from
22% to 14% over the last 3 months. What's going on and how do I fix it?"
Build flows from scratch:
"Build me a complete post-purchase email sequence for my Shopify store. I sell
premium coffee. Average order is $45, repeat purchase cycle is 30-45 days."
Get industry-specific advice:
"I'm launching a B2B SaaS product. What does my email marketing stack need
to look like from day one? Give me the flows, segments, and metrics I should
be tracking."
Draft copy:
"Write a win-back email sequence for subscribers who haven't opened in 90 days.
My brand voice is casual and direct. We sell fitness equipment."
Claude will pull from 65,000 words of research, benchmarks, frameworks, and real case studies to give you specific, actionable advice — not generic platitudes.
| # | Chapter | What you get | |---|---------|-------------| | 1 | The Fundamentals | Why email wins, the marketing stack, key metrics, common mistakes | | 2 | Building Your List | Organic growth, popups, double vs single opt-in, spam traps, validation | | 3 | Segmentation & Personalisation | RFM scoring, engagement tiers, zero-party data, waterfall segmentation | | 4 | The Emails That Make Money | Welcome series, abandoned cart, post-purchase, win-back — with timing and benchmarks | | 5 | Copywriting That Converts | Subject lines, preview text, body copy, CTAs, frameworks (PAS, AIDA, BAB) | | 6 | Design & Technical | Mobile-first, dark mode, accessibility, email client compatibility | | 7 | Deliverability | SPF, DKIM, DMARC, BIMI, sender reputation, IP warming, spam filters | | 8 | Testing & Optimisation | A/B testing, statistical significance, send time optimisation | | 9 | Analytics & Measurement | KPIs by campaign type, attribution, subscriber LTV, incrementality | | 10 | Compliance & Privacy | GDPR, CAN-SPAM, CASL, CCPA, Australian Spam Act, one-click unsubscribe | | 11 | Industry Playbooks | Segment-specific tactics for 19 verticals (see below) | | 12 | Choosing Your Platform | Honest comparison of Klaviyo, Mailchimp, Kit, beehiiv, Sendlane, and more | | 13 | Cold Email & B2B Outbound | Infrastructure, tools, writing, personalisation, follow-up sequences | | 14 | AI & the Future of Email | Where AI helps, where it doesn't, practical integration, MCP | | 15 | Company Case Studies | How Casper, Morning Brew, Duolingo, Spotify, and 6 others use email | | 16 | Expert Directory | 44 practitioners referenced throughout — who to follow and why |
Every vertical gets its own playbook with specific tactics, benchmarks, and automation flows:
Ecommerce DTC · SaaS B2B · SaaS B2C · Newsletter & Creator · Agency · Nonprofit · Healthcare · Financial Services · Real Estate · Travel & Hospitality · Education · Professional Services · Retail · Events · B2B Manufacturing · Restaurant & Food · Fitness · Media & Publishing · Marketplace & Platform
Insights from practitioners including Chad S. White (Zeta Global), Joanna Wiebe (Copyhackers), Chase Dimond (Structured Agency), Nathan Barry (Kit), Ann Handley (MarketingProfs), Troy Ericson (EmailDeliverability.com), Tyler Denk (beehiiv), Ben Settle (Email Players), and 36 others. Full directory in Chapter 16.
The complete 55,000-word Email Marketing Bible is available at emailmarketingskill.com — searchable, browsable, with all 16 chapters and 4 appendices.
908 sources across industry reports (Litmus, Klaviyo, Campaign Monitor, HubSpot, Salesforce), practitioner blogs, academic research, platform documentation, and community discussions from Reddit, Shopify forums, and X.
The research crawler is open source at github.com/CosmoBlk/emb-research.
Found an error? Have better data? Know a tactic that's missing? PRs and issues welcome. This is an open-source knowledge base — the more practitioners contribute, the better it gets for everyone.
MIT — use it however you want.
Built by George Hartley. Follow for updates.
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