Marketing Automation · Integration
Mailchimp
Add Mailchimp to your product for your customers, and give your AI agents governed access to it.
Mailchimp is where a smaller marketing team keeps its list, so an embedded Mailchimp integration is what stops them exporting contacts out of your product every week. The objects are audiences rather than lists now, with tags and segments layered on top, merge fields holding whatever that account decided to collect, campaigns and classic automations. Two practical things. Merge field tags differ per audience, so mapping is per customer and a field you assumed is a silent gap rather than an error. And the API host carries a datacenter prefix derived from the API key itself, so the base URL is not constant across customers and hard-coding one breaks the second account you connect. fastn resolves that per tenant and maintains the connector.
In your product
Embedded for your customers. Per-tenant auth, no per-customer code, maintained by fastn.
Let a business connect their own audience so contacts your product captures arrive with their tags already set.
Write merge field values that match what that audience collects, rather than a shape you fixed in advance.
Add or remove a tag to move somebody into a segment an automation is already watching.
Read campaign and automation reports so your product shows opens and clicks beside the contact it captured.
For your AI agents
Governed, audited access for the agents you build, through the MCP server.
An agent looks up a subscriber's tags and recent sends before answering a question about them.
An agent applies a permitted tag to a contact, and the audience it wrote to is recorded.
An agent compares the last few campaigns and says which subject lines did best.
Example prompt
Which tags does this subscriber have, and how did the last campaign sent to their segment perform?
Set up Mailchimp in 4 steps
- 01Enable the Mailchimp connector from your fastn dashboard.
- 02Have each customer authorise their own Mailchimp account, so calls run under their credentials rather than a shared key.
- 03Decide which campaigns, segments and subscribers your product needs, map those fields, then enable the actions and triggers you want.
- 04Call it from your product and expose it to your agents through the same governed connection.
Why teams use the Mailchimp integration
What you get by embedding it with fastn instead of building it yourself.
- Ship a Mailchimp integration without building it. Your customers connect their own Mailchimp account inside your product and work their campaigns, segments and subscribers there, with no per-customer code on your side.
- Handle the part that actually costs time: engagement data arrives as a high-volume event stream, so ordering and deduplication matter. fastn owns the auth, token refresh, rate limits, pagination and breaking-change fixes, so a Mailchimp update is not your on-call problem.
- One integration serves your product and your agents. The same governed Mailchimp connection powers in-product features and gives AI agents scoped, audited access, so you trigger and measure campaigns from inside your product without wiring it twice.
Used by these teams
Compare with
Constant Contact
Campaign Monitor
ActiveCampaignOften used alongside
Tools the same teams tend to run next to Mailchimp, across other categories.
Salesforce
HubSpot
Pipedrive
Zoho CRMMailchimp integration FAQ
How do I add a Mailchimp integration to my product?
Enable the Mailchimp connector in your fastn dashboard, then let each customer authenticate their own Mailchimp account. fastn handles the OAuth flow, token storage and refresh per tenant, so there is no Mailchimp client code in your app and no per-customer branch in your codebase. Setup is 4 steps.
Do my customers each connect their own Mailchimp account?
Yes. Every connection is scoped to the individual customer, so each authorises their own Mailchimp account and only ever sees their own campaigns, segments and subscribers. That per-tenant isolation is the point of an embedded integration: you support the long tail of customer setups without maintaining an integration per customer.
Can AI agents use this Mailchimp integration?
Yes. The same connection is exposed to your agents through the fastn MCP gateway, with permissions scoped per tenant and every call audited. An agent looks up a subscriber's tags and recent sends before answering a question about them.
Who maintains the Mailchimp integration?
fastn does. When Mailchimp changes an endpoint, deprecates a field or alters its auth, the fix lands in the connector rather than in your backlog, and your customers' connections keep working.
Can I trigger a Mailchimp campaign from an event in my product?
Yes. Product events can start a campaign, add a contact to a segment, or enrol someone in a journey, so lifecycle messaging follows what a user actually did rather than a nightly export.
Can I read engagement results back from Mailchimp?
Yes. Results come back scoped per tenant, so your product can act on them without one customer's data mixing with another's. What you get depends on the channel: opens, clicks, bounces and unsubscribes where there are sends, and impressions, spend and conversions where there are campaigns.
What can I build with the Mailchimp integration?
A common starting point: let a business connect their own audience so contacts your product captures arrive with their tags already set. Teams also use it for the other use cases listed above, and expose it to agents for governed reads and writes.
How much does the Mailchimp integration cost?
It is included. Pricing is based on connected accounts, not on how many connectors you enable, so adding Mailchimp does not change your per-connector cost. You can start free with 3 connected accounts.
Add Mailchimp to your product
Start free with 3 connected accounts. No sales call required, and no per-customer integration code.