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Mailchimp

The Mailchimp API and Mandrill, Explained (and Where to Actually Get Your Key)

Mailchimp's Marketing API (what most people mean by "the Mailchimp API") covers audiences, campaigns, and automation triggers, and your API key lives under Account > Extras > API keys in your Mailchimp account. Mandrill is a separate product, Mailchimp's transactional email service for one-off, triggered messages like receipts and password resets, with its own API and its own key, and the two get confused constantly.

Getting and using an API key

Generate a Marketing API key from Account & billing > Extras > API keys. The key's suffix tells you which data center your account lives on, which matters because every API call has to hit that specific data center's URL, a common first mistake when wiring up an integration by hand.

The API itself is well documented and covers list and audience management, campaign creation and sending, automation enrollment, and reporting data pulled back out. It's the foundation almost all custom Mailchimp integration work builds on, including the CRM and e-commerce syncs described on our Mailchimp integrations page →.

Webhooks run the other direction: Mailchimp calls a URL you provide when something happens (a subscribe, an unsubscribe, a campaign send), which is how you get real-time Mailchimp events into another system without polling the API on a schedule.

What Mandrill actually is

Mandrill handles transactional email: messages triggered by a specific user action, a receipt, a password reset, a shipping confirmation, as opposed to a campaign you send to an audience on purpose. It used to be a free feature bundled into every Mailchimp account; it's now a separate, specifically transactional-focused product with its own pricing and its own API key, generated inside Mandrill itself, not your main Mailchimp account.

That split causes real confusion, which is exactly why "mandrill mailchimp" and "what is mandrillapp" show up as genuine, frequent searches. If your business needs to send receipts or password resets reliably at scale, and you're trying to do it through a regular Mailchimp campaign, that's the wrong tool for the job, Mandrill is built for exactly this and a campaign send isn't.

What that looks like built out

Transactional sends wired through Mandrill, not a campaign

Receipts, password resets, and shipping confirmations route through Mandrill's API the moment the triggering event happens in your actual system, instead of getting bundled awkwardly into a regular Mailchimp send.

Webhook-driven sync instead of scheduled polling

Mailchimp's webhooks feed subscribe, unsubscribe, and campaign events into your other systems in real time, so a contact's status stays accurate everywhere without a recurring API pull job.

What are you trying to build against the Mailchimp API right now?

Whether it's a sync, a transactional send, or something that needs both, tell us what you're stuck on.

Let's talk

Stuck wiring up the Mailchimp API, or still sending transactional email through a regular campaign?

Tell us what you're trying to connect, and whether what you actually need is the Marketing API, Mandrill, or both. We'll build it properly the first time. The Mailchimp API is one example; n-frames builds whatever integration your business actually needs.

Let's talk

Frequently Asked Questions

Where do I find my Mailchimp API key?+
In your Mailchimp account under Account & billing > Extras > API keys. You can generate a new key there at any time; note the data center suffix at the end of the key, since every API call needs to target that specific data center's URL.
Is Mandrill the same thing as Mailchimp?+
No. Mandrill is a separate transactional email product that Mailchimp owns, used for triggered one-off messages like receipts and password resets rather than campaigns. It has its own account, its own API key, and its own pricing, distinct from your main Mailchimp subscription.
What is a transactional email?+
An email triggered automatically by a specific user action, a password reset, an order receipt, a shipping notice, sent to one person based on something they just did, as opposed to a campaign sent intentionally to a list or segment.
Does Mailchimp have webhooks?+
Yes. You can configure a webhook URL that Mailchimp calls when events happen, subscribes, unsubscribes, campaign sends, and more, which is the standard way to get real-time Mailchimp activity into another system without polling the API on a schedule.
Is the Mailchimp API free to use?+
Using the API itself doesn't cost extra beyond your existing Mailchimp plan, though your plan's rate limits and feature access still apply to what the API can do. Mandrill, by contrast, is billed separately based on transactional email volume.

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