AI Write a Substack Newsletter Post
Use AI to write a Substack newsletter that subscribers actually open, read, and share — from subject line to closing CTA.
Goal of This Task
You run a Substack newsletter (or want to start one) and need a workflow for writing posts that subscribers open, read to the end, and share. This covers the full pipeline: subject line, opening hook, body structure, and paid-tier teaser.
Recommended Workflow
Step 1: Define the post angle
Help me write a Substack newsletter post. Info:
Newsletter topic/niche: [e.g., "AI tools for solopreneurs"]
This post's angle: [e.g., "I tested 10 AI scheduling tools for a month — here is what happened"]
Subscriber level: [e.g., "mostly free subscribers, trying to convert to paid"]
Target length: [e.g., 800-1200 words]
Tone: [e.g., "personal and analytical" or "opinionated and punchy"]
Step 2: Generate subject lines (the open-rate lever)
ChatGPT
免费替代: Claude
Strong at subject line patterns and A/B testing logic
The subject line is the single highest-leverage element of a newsletter. It determines your open rate — and open rate determines everything downstream. Substack shows subject lines in email inboxes, where they compete with dozens of other emails.
Give me 8 subject line options. Requirements:
- Under 50 characters each
- Use these patterns (2 each):
- Curiosity gap ("The AI tool I stopped using (and why)")
- Specific number ("I tested 10 AI schedulers for 30 days")
- Contrarian ("Productivity apps are making you less productive")
- Personal story ("How I accidentally built an AI side business")
- No clickbait — the subject must match the post content
- No ALL CAPS or excessive punctuation
Step 3: Write the opening paragraph
Give me 3 opening paragraph options for this newsletter post. Requirements:
- Each under 80 words
- Start with the point, not the context (no "In this issue..." or "I have been thinking about...")
- Pattern A: Start with a surprising result
- Pattern B: Start with a question the reader has been asking
- Pattern C: Start with a one-sentence story
Step 4: Write the full post segment by segment
Write this newsletter post section by section. This is section [N].
Section content: [e.g., "Tool 3: Motion — what it does well, where it fails, and who it is for"]
Target length: [e.g., 200 words]
Requirements:
- Conversational but substantive — like an email to a smart friend
- Include one specific data point or screenshot description
- If this is a free section, end with a teaser for the paid section
- If this is a paid section, deliver the full value promised
Step 5: Human polish (mandatory)
Newsletter readers are loyal because of your voice, not AI's. You must:
- Remove AI newsletter cliches: "I have been thinking a lot about," "Let us dive in," "In this week's issue." Delete all of these.
- Inject personal experience: the reason subscribers pay you is for your unique perspective. Every section should have at least one sentence that AI could not have written — your opinion, your data, your story.
- Test the subject line on yourself: would you open this email if it arrived in your inbox at 7 AM alongside 20 others?
- Preview on mobile: 60 percent of newsletter reads happen on mobile. Check that paragraphs are short and scannable.
Recommended Tool Stack
| Tool | Use Case | Free? |
|---|---|---|
| ChatGPT (GPT-4o) | Draft generation, subject line testing | Limited free tier |
| Claude | Long-form structure, voice matching | Limited free tier |
| Substack | Publishing, analytics, subscriber management | Free |
| Beehiiv (alternative) | Newsletter platform with built-in ad network | Free tier |
Platform Notes
- Subject line determines open rate. Substack delivers via email. Your subject line competes in an inbox. Under 50 characters avoids truncation on mobile. Test 2-3 options and pick the one that feels most "must-open."
- The first paragraph determines scroll depth. Substack analytics show "engaged time" — how long readers spend. If the first paragraph is context-setting or throat-clearing, readers bounce. Start with value.
- Free-to-paid conversion is about unique value. Substack's business model is paid subscriptions. Your free posts must demonstrate enough value that readers believe the paid tier is worth it. AI can help you structure the teaser, but the unique insight that justifies payment must be yours.
- Consistency beats virality. Substack rewards a regular cadence (weekly or biweekly). One viral post brings temporary spikes; 50 consistent posts build a subscriber base that compounds. Pick a schedule you can sustain for a year.
FAQ
Can AI help me find newsletter topics subscribers will pay for?
Yes. Feed AI your top 10 most-opened past posts and ask: "What patterns do you see? What topics get the highest engagement?" AI can identify themes you may not notice. But the topic must connect to your expertise — AI can find patterns in your data, but it cannot generate the original experience that makes subscribers pay.
Should I disclose that I use AI to write my newsletter?
Disclosure is not required for AI-assisted writing (where you edit and own the final output). It is required for AI-generated content (where you publish AI output with minimal editing). The line is editorial judgment: if a reader would feel deceived learning AI was involved, disclose. If AI was a drafting tool like a spellchecker, disclosure is unnecessary. Most newsletters use AI as a drafting tool without disclosure.
What is the ideal newsletter length?
For free posts: 600-1200 words. For paid posts: 1200-2500 words (paid subscribers expect more depth). The best metric is not word count but "engaged time" — Substack shows how long readers spend. If your average engaged time is under 1 minute, your posts are too long or not compelling enough. If it is over 3 minutes, you have an engaged audience and can experiment with longer deep-dives.