For Email Marketing Specialists ·
What you'll accomplish
By the end of this guide, you'll have a Custom GPT in ChatGPT that any team member can use to produce brand-consistent email copy without needing to understand prompt engineering. Your brand voice, audience context, ESP conventions, and copy standards are baked into the GPT — so a contractor, junior marketer, or agency partner produces on-brand output from day one. Every email generated will follow your templates, avoid your banned phrases, and sound like your brand.
What you'll need
Before building the GPT, compile these in text format:
File 1: Brand Voice Bible (create if you don't have one)
File 2: Email Templates
SUBJECT LINE TEMPLATE:
- Max 50 characters
- Never start with "Just" or "We"
- Always test: Urgency angle vs. Benefit angle
- Structure: [Primary Hook] — [Context or Urgency]
- Examples of on-brand subject lines: [paste 10 of your best]
PREVIEW TEXT TEMPLATE:
- 85-100 characters
- Never repeat the subject line verbatim
- Should add context or deepen the hook
- Examples: [paste 5]
EMAIL OPENER TEMPLATE:
- Never start with "We" — always open with the reader's world
- Maximum 1 sentence before the value proposition
- On-brand openers: [paste 5 examples]
CTA TEMPLATE:
- Specific action + implied benefit ("Shop the Sale" not "Click Here")
- 2-4 words maximum
- CTA bank: [list your standard CTAs by campaign type]
File 3: Audience Personas
File 4: Performance Benchmarks
Click the Configure tab for direct control:
Name: "[Brand Name] Email Copywriter"
Description: "Writes email marketing copy for [Brand Name] — campaigns, sequences, subject lines, and re-engagement. Produces on-brand output instantly."
Instructions (paste this, customized):
You are the email marketing copywriter for [Brand Name]. You write all email campaigns, automation sequences, subject lines, and re-engagement copy.
BRAND IDENTITY:
[Paste your brand voice summary — 2-3 paragraphs]
AUDIENCE:
[Paste your primary persona description]
EMAIL STANDARDS:
- Subject lines: under 50 characters, never start with "We" or "Just"
- Preview text: 85-100 characters, never repeats subject line
- Email body: 150-200 words for promotional, 100-150 for re-engagement
- CTAs: specific action + benefit, 2-4 words
- Opener: always starts with reader's perspective, never "We are excited to..."
- Closer: [your standard sign-off style]
WORDS WE USE: [list]
WORDS WE NEVER USE: [list]
WHAT I DELIVER FOR EVERY REQUEST:
Unless instructed otherwise, I always provide:
1. Subject line (3 variants — different angles)
2. Preview text (matching each subject line)
3. Full email body
4. CTA text (2-3 options)
5. A brief note on the strategic choice I made
I write in [Brand Name]'s voice — not generic marketing copy.
If the request is unclear, I ask 1 clarifying question before writing.
Knowledge: Upload your 4 documents from Step 1 using the + button in the Knowledge section. The GPT will reference these when generating copy.
Capabilities:
These appear on the GPT's homepage and guide users to get started quickly:
Write a promotional email for a weekend flash sale
Write a 5-email welcome series for new subscribers
Give me 10 subject line variants for our product launch
Rewrite this email in our brand voice: [paste email]
Write a win-back email for subscribers inactive 90 days
Click Save → View GPT → test with real requests:
Test 1 — Brand voice accuracy: Type: "Write a promotional email for 30% off our full catalog, ending Friday. Audience: past buyers."
Check: Does it sound like your brand? Does it follow your subject line format? Does it avoid your banned phrases?
Test 2 — Sequence generation: Type: "Write a 3-email abandoned cart sequence. Product: [your product type]. Average order value: $75."
Check: Does each email feel distinct? Does the discount introduction timing match your policy?
Test 3 — Voice correction: If the first output sounds off, respond: "That doesn't sound like us — we're more [adjective]. Rewrite with [specific adjustment]."
The GPT should learn from corrections within a conversation session.