This article walks you through connecting Mailchimp to an OptiMonk campaign. Once you are done, everyone who fills out your popup form is added to the Mailchimp audience you picked — no exports, no copy-paste.
Before you start: you need a campaign whose popup is already built (the field mapping is read from the input fields of your popup) and a Mailchimp account. In the OptiMonk provider list, Mailchimp is spelled Mailchimp, and you find it in the Popular row.
1. Get your Mailchimp API key
Log in to your Mailchimp account in a new browser window and click your icon in the bottom left corner, then open the Account menu. Select API keys under Extras. If you do not have a key yet, scroll down and select Create A Key. Copy the key.
OptiMonk's own hint for this field says it in one line: You can view or generate API keys in your MailChimp account. Go to [Account Name] -> Account Setting -> Extras -> API keys (eg.: 68a23fc3456fe66f57acf5c04a19907c-us3)
2. Connect Mailchimp to your campaign
Open Campaigns in the left menu and click the campaign you want to connect with Mailchimp.
Open the Integrations tab of the campaign.
Click Add integration. If this is the campaign's first one, the same step is offered as Connect your email or SMS tool.
Provider step: pick Mailchimp. If you have connected Mailchimp before, the account is listed at the top under Your connected accounts — pick it there and jump to step 6.
Account step: paste the key into API key. You can also give the connection a name (Name (optional)) so you recognise it later. Click Connect.
If the key is wrong, the step says Connection failed — check the credentials and keeps what you typed, so you can correct it.
Settings step:
List — the audience new signups should join. (Mailchimp calls a list an Audience.)
Groups (optional) — the interest groups new subscribers should get inside that audience. The groups are loaded for the audience you picked, and they are listed as tick boxes, so you can tick several or none. Mailchimp has a short guide on groups: https://mailchimp.com/help/getting-started-with-groups/
Click Continue.
Field mapping step: decide where each popup field goes in Mailchimp (see below), then click Save integration.
That's it. Whenever a visitor signs up through your popup, they are added to the Mailchimp audience you picked. Their data also stays in OptiMonk — you find it under Leads in the left menu.
Draft vs. live: if the campaign has not been published yet, the integration is shown with a Draft pill and the note Saved as draft — it goes live when you publish the campaign. On a published campaign, it shows as Active and is applied right away.
Field mapping
The mapping table has two columns: Popup field on the left (every input your popup collects) and Mailchimp field on the right. OptiMonk pre-fills the mapping with its own suggestions, so in most cases you only need to check it.
The email row is fixed — it always maps to Mailchimp's email field.
Pick Don't sync for any popup field you don't want to send.
Under Static fields you can send a fixed value with every submission. Click Add static field, type the value on the left — for example,
OptiMonk, so you always know which subscribers came from your popup — and choose the Mailchimp field on the right.
Adding more fields on the Mailchimp side
Mailchimp creates a few fields automatically when you create an audience (Email Address, Address, First Name, Last Name, Phone Number). If you need more, add them to the audience's signup form, and they will appear in the right-hand column here:
Click Audience in the menu bar on the left in Mailchimp, then select Signup forms.
Select Form builder on the next page.
Add the fields you need. These are the fields you will be able to map your OptiMonk popup fields to.
💡 It is worth comparing what your popup asks for with what your Mailchimp audience stores: a value with nowhere to go in Mailchimp is simply not transferred.
Where to check the result
In Mailchimp: open Audience, then All contacts — your new subscribers are in the table with the data you mapped.
In OptiMonk: open Leads in the left menu.
Change or remove the integration
The Integrations tab lists every integration on the campaign with its list name.
Change list reopens the wizard at the Settings step, so you can change the audience, the groups, or the mapping.
Remove takes the integration off this campaign: Remove from this campaign? The account connection stays and can be added again. Your Mailchimp credentials are not deleted, so you can reuse them on another campaign.
Double opt-in
The campaign integration wizard has no double opt-in switch. Whether a new subscriber has to confirm their address is decided on the Mailchimp side, by the audience's own settings: https://mailchimp.com/help/about-double-opt-in/