Every marketer I talk to right now has the same question. "What's your AI stack?"
Not because they want another SaaS bill. Because they know if they do not figure this out in the next 12 months, they are going to fall behind marketers who did.
Here is what I actually run. Not a scraped roundup. Not affiliate driven. The tools I pay for out of my own pocket every month.
What I mean by "stack" (and what I don't)
A stack is not a shopping list of 15 tools you might use one day. A stack is the specific set of tools you use every week to run your operation.
My rule: if I have not opened a tool in 30 days, it is not part of the stack. It gets cancelled.
Everything below I have used in the last 30 days. If I list it, I use it.
The ESPs that are shipping real AI vs bolt-on features
Most ESP "AI" is a subject line generator wrapped in a marketing announcement. That is not AI. That is a ChatGPT API call with a nicer button.
Here is who is actually building real AI features in 2026:
- Klaviyo. Predictive segmentation, lifetime value modeling, churn risk scoring. If you run ecommerce, this is the tier above everyone else.
- ActiveCampaign. AI automation builder that reads your goal and drafts a workflow. Genuinely useful once you learn to prompt it.
- Flodesk. They shipped two real AI products in 2026. First was the Claude and ChatGPT integration, which lets you ask an AI about your account and get a real answer. Second was Flodesk Studio, an AI design app.
The rest are catching up. Mailchimp shipped AI features that feel like a checkbox exercise. Kit is deliberately slow. Beehiiv is focused on the creator economy playbook, less on AI.
Subject line generation: Lavender, Copy.ai, or ChatGPT?
I have tested all three. For pure subject line ideation, my ranking:
- Lavender. Purpose built for email. Gives you a score, tells you why, and generates variants that actually feel like humans wrote them. $49 a month.
- ChatGPT with a good prompt. Free to $20 a month. Comparable quality if you prompt it well. Slower and requires more editing.
- Copy.ai. Fine. Not better than ChatGPT for this specific task.
My workflow: use Lavender for the first pass, then rewrite the winner in my own voice. Never send the raw AI output.
AI-powered segmentation: which ESPs do it well
This is where AI actually earns its keep in email marketing. Not in copywriting. In segmentation.
Klaviyo's predictive segments are the current gold standard. It looks at behavior across your entire store and identifies subscribers who are about to churn, likely to buy again, or high LTV candidates. Then it lets you build automations off those predictions.
ActiveCampaign has a version of this called Predictive Sending. Less sophisticated than Klaviyo but genuinely useful for non ecommerce use cases.
Everyone else is doing rule based segmentation and calling it AI. It is not. That is just filters.
The most valuable AI in email marketing right now is not writing your emails. It is deciding who should get them. Predictive segmentation is where the real leverage is.
— Carlos Gil, Editor in Chief, BestSendsSend time optimization: when it actually matters
Send time AI is oversold. For a small list (under 5K subscribers), the delta between 8am and 10am send is negligible. Save the money.
For a list of 25K or more, it starts to matter. A 3% lift in opens on a 100K send is 3,000 more human eyeballs. Compound that over a year and it pays for itself.
Tools I have tested: Seventh Sense, Klaviyo's Smart Sending, and Mailchimp's Send Time Optimization. All roughly equivalent. Pick whichever is native to your ESP.
Analytics and reporting: Claude and ChatGPT integrations
This is where 2026 got interesting.
Flodesk launched a direct integration with Claude and ChatGPT earlier this year. You can literally ask Claude "which of my last 10 campaigns had the highest revenue per subscriber" and it pulls the answer from your Flodesk account and shows you the math.
I use this every Monday morning. Ten minutes of Q and A with Claude replaces an hour of digging through dashboards.
Nobody else has shipped this yet. Klaviyo is rumored to be building it. Kit has said no comment. If your ESP does not have real conversational analytics by end of 2026, they are behind.
The stack I actually run (with monthly cost breakdown)
Full transparency on what I pay every month:
- ESP: ActiveCampaign, Plus plan. $90/month.
- Design: Flodesk Studio. Free in beta right now.
- AI assistant: Claude Pro. $20/month.
- AI assistant (team): ChatGPT Team. $60/month.
- Subject lines: Lavender. $49/month.
- Send time: Seventh Sense. $30/month.
- Analytics: Improvado. $90/month.
Total: $339 a month. For an operation that generates 6 figures a year in newsletter revenue, that is nothing.
Lean version if you are just starting: KitAffiliate ($29), ChatGPT ($20), Lavender free tier. Under $50 a month.
What I've tried and stopped using
Tools I paid for, tested for at least 60 days, and cancelled:
- Jasper. Great for blog posts, mediocre for email. Not worth $49 a month if you already have ChatGPT.
- Persado. Enterprise pricing for what amounts to a fancier subject line generator.
- Copy.ai. Solid product. Just did not fit into my workflow after ChatGPT got better.
- Mailchimp Standard. Cancelled after their 2026 price hike. Full context in my Mailchimp switch guide.
None of these are bad products. They just did not earn their spot in my monthly budget.
Depends on the ESP. Most native AI is thin. It generates subject lines and rewrites body copy, and that is it. If you want real segmentation, predictive send times, and analytics that actually explain anything, you still need dedicated tools alongside your ESP.