AI assistant
An editor that reads your mind.
Tell Postern what you want. It reads your template, understands the context, and makes the precise edit. No invented stats. No silent rewrites of paragraphs you liked.
How it works
Precise AI, not generic GPT.
AI has earned a reputation: ask for a headline, get marketing-speak nonsense. We took that personally and built around it.
When you ask for a change, Postern goes through five steps before anything saves:
- Reads your template — HTML, blocks, merge tags.
- Loads your brand voice via the system prompt.
- Makes the edit at the right place, in the right magnitude.
- Shows you the diff before applying.
- Applies only when you accept.
No surprises. No rewriting your whole email when you asked about one paragraph. Precision.
Real prompts, real results
What you can actually ask.
Prompt
"Make the headline punchier and add a sense of urgency."
Headline rewrite + tone shift
Before
Check out our new features
After
Your competitors already know. Here’s what’s new.
Prompt
"Add social proof above the footer."
Block insertion with context-aware placement
Before
[no social-proof block]
After
A new “Trusted by 10K+ teams” block, placed in the footer.
Prompt
"Make this 30% shorter but keep all the key info."
Content condensing + merge-tag preservation
Before
3-paragraph body, ~400 words
After
1-paragraph body, ~280 words; merge tags preserved
Honest limitations
What it does well — and what it doesn’t.
Marketing pages usually skip this section. We think you deserve it before you commit.
Good at
- Rewriting existing copy (shorter, punchier, friendlier)
- Drafting CTA copy that respects the surrounding tone
- Shifting tone (formal ↔ casual, executive ↔ neighbourly)
- Inserting blocks where they make narrative sense
- Preserving merge tags through rewrites
Not good at — yet
- Creating from a blank page — it needs your template as context
- Inventing customer numbers or product specs
- Replacing your brand voice — it amplifies what you provide
- Writing legal or regulated copy unaided
Safety + transparency
AI you can put on a security review.
No training on your emails.
Your templates and prompt history are never used to train our models. Per GDPR and the contract you signed at signup. Anthropic and AWS Bedrock both run under no-training agreements.
Audited prompts.
The system prompts we send to the model are published. No hidden instructions. If we change them, the changelog tells you.
Human in the loop.
You review every change before it lands. We never auto-apply. The diff appears, you accept or iterate. Control stays with you.
Use case
A 2-hour job, in 30 minutes.
Freelancer brief: welcome email for a SaaS app, friendly tone, three-part series.
Old way (≈ 2 hours)
- 1 hr — design template from scratch
- 30 min — write copy
- 30 min — adjust tone after client review
- 30 min — test send + QA
With Postern (≈ 30 min)
- 10 min — pick template
- 10 min — describe the SaaS to the AI
- 5 min — request a tone adjustment
- 5 min — add the social proof block
Try these
Twelve prompts to start with.
Copy any of these, paste into the AI panel, tweak to taste. Most are short on purpose.
- Make this headline shorter and add a number — like “5 ways to…”.
- Change the tone from formal to friendly. Keep the same information.
- Add a CTA button above the footer. Label it “Get started”.
- Highlight the three main benefits in the body. Bold the value verbs.
- Personalise this for VIP subscribers. Add “exclusive” and “early access”.
- Rewrite the subject line for a higher open rate. Use these keywords: …
- Trim the intro. Keep paragraphs under 50 words.
- Replace the placeholder hero image with one that matches the headline.
- Translate the body to plain English. No marketing-speak.
- Make this iPad-friendlier. Bigger buttons, fewer columns.
- Add a P.S. with a soft second CTA.
- Strip everything that isn’t about the offer. One paragraph max.
AI included on every tier.
Free includes 50 generations / month. Starter includes 500. Pro and Business are unlimited. Enterprise adds priority queueing for time-sensitive campaigns.
Full breakdown on the pricing page.
See it in action.
Sign up free, pick a template, ask the AI to change something. Three minutes to first edit.