AI assist
A writing assistant, when you want one.
Draft a campaign from a short brief, get subject lines and preview text, and rewrite what you highlight. Powered by Claude, and included on every paid plan.
Draft a whole campaign
Give it a short brief and get back a subject line, preview text, and full body. Then make it your own.
Subject line ideas
Generate five alternative subject lines and pick the one that fits.
Edit with AI
Highlight any text and describe the change in plain words, and day3 rewrites just that selection.
Included on every paid plan
From $1/mo up. Bigger plans carry a bigger AI allowance, but no paid plan is without one. Every AI output stays inbox-ready with your merge tags intact.
Where AI helps and where it doesn't
The assistant is good at the parts of a product email that are structurally the same every time: turning a list of shipped changes into readable prose, producing five subject lines so you can reject four, and writing preview text, which almost everyone leaves empty and which materially affects whether an email gets opened.
It is less good at knowing what matters. It has your brief and nothing else: not the support thread that prompted the change, not the customer who asked for it, not the thing you'd rather not draw attention to yet. Which is why it drafts into the composer rather than sending, and why nothing in day3 will email your list without you clicking send.
If you already write in an editor, the MCP server is usually the better path than the in-app assistant. Describing the email in Claude Code or Cursor, where your changelog and your commit history already are, produces a better draft than describing it from scratch in a text box, and it arrives in day3 as editable blocks either way.
Questions
- Which plans include the AI assistant?
- Every paid plan, starting at $1/mo. Higher tiers come with a larger AI allowance. The free tier has none. It can send in sandbox mode, but the writing assistant is what a paid plan turns on.
- Which AI model does day3 use?
- It's powered by Claude (via OpenRouter). It can draft a campaign, suggest subject lines, write preview text, and rewrite selected copy, all kept inbox-ready.
- What happens when I use up my AI allowance?
- The AI tools switch off until the allowance resets. Writing by hand carries on untouched. Moving up a plan buys a bigger allowance.
- Can I cap what AI usage costs me?
- Yes. Set a monthly AI budget per account and assisted writing stops there. That's separate from the plan allowance and exists so that generous use can't turn into a surprise line item.
- Will AI-written emails break my formatting or merge tags?
- No. Output comes back as the same inbox-safe blocks the composer uses, with merge tags like {{first_name}} left intact rather than rewritten into prose. You can edit any of it by hand afterwards.
- Do I have to use the AI at all?
- No. It's a panel you open, not a step in the flow. Every campaign can be written entirely by hand, and the free tier has no AI allowance at all without losing any sending capability.
Related
- CampaignsOne email to one audience. Compose, test, and send it, all on a single screen. No funnels, no approval maze.Read on
- APIOne REST API for your app's transactional email, your audiences, and your campaigns, plus an MCP server that turns your AI editor into a composer. Built so migrating from another provider is one script and staying in sync afterwards is a webhook handler.Read on
- PricingNine plans from $1/mo for 1,000 emails to $220/mo for 1,000,000. Unlimited subscribers on all of them.Read on
- Indie developersEmail your users about what's new, without paying per subscriber or learning a marketing platform. Built for a team of one.Read on
- day3 vs Kit (ConvertKit)Kit is built for creators growing audiences and sales funnels, and it prices by subscriber count.Read on
- How send-based pricing worksWhat counts as a send, what happens at the monthly cap, and why list size never moves the bill.Read on