Why we built an email platform that understands AI agents
The problem
Email subscription management sounds like a solved problem. Mailchimp has been around since 2001. ConvertKit since 2013. So why yet another platform?
Because the world has changed — and the existing tools have not kept up.
1. Developers want APIs, not drag-and-drop builders
When you build a SaaS app and want to integrate email preferences, you need an API. Not a “marketing suite” with 200 features, of which you use 3. You want:
POST /subscribers— create a subscriberPUT /subscribers/{id}/tags— assign tags- Done.
Mailchimp has an API. But it was bolted onto a UI-first product after the fact. You notice that at every turn: inconsistent endpoint naming, missing webhook signatures, no real multi-tenant isolation.
2. Subscribers are not passive recipients
With every email platform I know, the preference centre is an unsubscribe form. “Would you like fewer emails? Unsubscribe here.”
Why can a subscriber not say: “I would also like to be informed about product updates”? Why is opt-in only possible at the first point of contact?
SubscribeFlow turns that around. The preference centre is a bidirectional dialogue. Subscribers can:
- Subscribe to new tags (not just unsubscribe from existing ones)
- Actively manage their interests
- Export data and delete their account (GDPR)
The result: 34% fewer unsubscribes in our own tests, because subscribers can control granularly what they receive.
3. AI agents are the new power users
This is where it gets exciting. Since Anthropic released the Model Context Protocol (MCP), AI assistants like Claude can interact directly with external tools.
SubscribeFlow has a native MCP server. That means:
You: "Claude, how many active subscribers do we have with the tag 'newsletter'?"
Claude: "427 active subscribers are tagged with 'newsletter'."
You: "Create a campaign for everyone with 'product-updates', subject 'New features in March'"
Claude: "Campaign created. 1,203 recipients. Shall I send it?"
No opening a dashboard. No filling in a form. Just talk.
Does that sound like a gimmick? It is not. For teams that work with subscriber data every day, it saves hours per week.
What SubscribeFlow offers technically
- REST API with full OpenAPI documentation
- Python SDK and TypeScript SDK (on PyPI and npm)
- MCP server for Claude Desktop and Claude Code
- MJML templates with a variable system
- Campaigns with tag-based segmentation
- Webhooks with HMAC-SHA256 signature verification
- Multi-tenant SaaS with Stripe billing
- Custom domains for email senders (Professional)
Pricing that makes sense
| Plan | Price | Subscribers | Emails/month |
|---|---|---|---|
| Free | CHF 0 | 500 | 1,000 |
| Starter | CHF 19/mo | 5,000 | 10,000 |
| Professional | CHF 49/mo | 50,000 | 100,000 |
For comparison: Mailchimp costs $34/mo for 2,500 subscribers. ConvertKit $25/mo for 1,000.
What comes next
We are working on:
- Analytics dashboard — open and click rates, subscriber growth
- A/B testing — test subject lines and content
- AI-assisted send optimisation — the optimal time per subscriber
Conclusion
SubscribeFlow is not for everyone. If you need a marketing suite with landing pages and social media management, take Mailchimp.
But if you:
- Are looking for an API-first email platform
- Want to give your subscribers real control over their preferences
- Want to integrate AI agents into your workflow
- Work in the DACH region and take GDPR/DSG seriously
Then give SubscribeFlow a try.
📖 Documentation: https://docs.subscribeflow.net 🚀 Get started: https://subscribeflow.net 💬 Feedback: https://subscribeflow.net/feedback
Daniel Senften is the founder of Talent Factory GmbH and is building SubscribeFlow as an open-core email subscription platform.