Your Mailchimp WordPress plugin should do two things well: connect without hassle and give you enough control to build the signup experience your audience actually deserves. The Ninja Forms Mailchimp add-on does both, turning any form on your WordPress site into a direct pipeline to your Mailchimp Audiences.
With the Mailchimp add-on, you can:
Key Features of the Mailchimp Add-On
Simple API connection and fast setup
Getting started takes minutes. Paste your Mailchimp API key into Ninja Forms settings, choose your Audience, and your WordPress form is connected. A pre-built Mailchimp Signup Form template is included so you can launch immediately without building from scratch.
Audience field mapping with merge tags
Map any form field to the corresponding field in your Mailchimp Audience using merge tags. Need to collect more than just a name and email? Create custom Audience fields in Mailchimp and they will appear automatically in the mapping interface once you resync. Checkbox list, radio list, and select fields are also supported for more complex data collection.
Tags support
Assign one or more tags to every subscriber who submits your form. Tags are entered as a comma-separated list in the Mailchimp action settings and must match tags you have already created in your Mailchimp account. This makes it easy to segment new subscribers the moment they sign up, without any extra steps in Mailchimp.
Interest groups
Route subscribers into specific Mailchimp Interest Groups based on the form they submitted. Groups you have created in your Mailchimp Audience will appear in the action settings, ready to toggle on. For more advanced routing, you can add multiple Mailchimp actions to a single form and use the Conditional Logic add-on to assign subscribers to different groups based on what they selected.
Mailchimp Opt-in field
The dedicated Mailchimp Opt-in field gives subscribers a clear choice at the point of submission. When the field is checked, the Mailchimp action runs and the contact is added to your Audience. When it is left unchecked, the action is skipped entirely. No conditional logic setup required.
Double opt-in
Protect your list quality and stay compliant with email marketing best practices by enabling double opt-in on any form. When this option is turned on in the Mailchimp action’s Advanced settings, subscribers receive a confirmation email from Mailchimp before being added to your Audience.
Grow Your Mailing List on Your Terms
The Mailchimp add-on is included with any Ninja Forms membership, or available as a standalone purchase. Pick your plan above and start connecting your WordPress forms to Mailchimp today.
Priority email support and 14-day money-back guarantee included.
How the Mailchimp WordPress Plugin Integration Works
The add-on works as a form action inside Ninja Forms. Once you connect your Mailchimp API key, you can add a Mailchimp action to any form on your WordPress site, not just dedicated signup forms. Every time someone submits the form, their information flows directly to the Audience you selected.
Field mapping happens through Mailchimp’s native merge tag system. Whatever fields you have defined in your Mailchimp Audience will appear in the mapping interface. This means your WordPress forms can send names, email addresses, phone numbers, custom fields, and more, all going to exactly the right place in Mailchimp.
If your Audience lists are not showing up after you add your API key, use the refresh icon next to the List label in the Mailchimp action settings to pull the latest data from your account.
Building a Mailchimp Signup Form in WordPress
The fastest path is the included Mailchimp Signup Form template. From your Ninja Forms dashboard, click Add New, select the Mailchimp Signup template, choose your Audience, name the form, and click Create. Your form is ready to publish.
Prefer to add Mailchimp to a form you have already built? Go to the Emails and Actions tab in the form editor, click Add New Action, and select Mailchimp from the list. Map your fields, configure any tags or Interest Groups, and save. That form is now synced to your Audience with every submission.
Common Use Cases
- Grow a newsletter Audience from your WordPress site: Add a Mailchimp action to a simple contact or signup form and start building your list immediately. Start with a pre-built Mailchimp Signup Form template or build your own.
- Segment subscribers at the point of signup: Use Interest Groups and tags to organize new subscribers automatically, so your Mailchimp Audiences stay clean without manual sorting.
- Add list opt-in to any existing form: Turn a contact form, event registration, or quote request into a list-building opportunity by adding the Mailchimp Opt-in field. Visitors choose to subscribe; you do not have to change the form’s primary purpose.
- Give subscribers control over what they receive: Map form fields to Interest Groups so subscribers can self-select the topics or lists they want to hear from, reducing unsubscribes.
- Maintain a clean, confirmed list: Enable double opt-in to ensure every address on your Mailchimp Audience belongs to someone who actively confirmed their subscription.
- Collect richer subscriber data: Map custom Audience fields to form fields to capture job titles, locations, preferences, or any other information your email campaigns need to be relevant.
Connect WordPress to Mailchimp Without the Guesswork
The Mailchimp add-on is included with any Ninja Forms membership, or available as a standalone purchase. Choose your plan above and start turning every form submission into a list-building opportunity.
Priority email support and 14-day money-back guarantee included.
Can I connect Mailchimp to any form on my WordPress site?
Yes. You can add a Mailchimp action to any form built with Ninja Forms, not just dedicated signup forms. This makes it easy to add list-building to contact forms, event registrations, quote requests, or any other form on your site.
What is the Mailchimp Opt-in field?
The Mailchimp Opt-in is a dedicated field type you add to your form. When a visitor checks it, the Mailchimp action runs and they are added to your Audience. When left unchecked, the action is skipped. It requires no conditional logic setup and is the simplest way to make list subscription optional.
Does the Mailchimp WordPress plugin support double opt-in?
Yes. You can enable double opt-in in the Advanced settings of the Mailchimp action. When enabled, Mailchimp sends a confirmation email to the subscriber before adding them to your Audience, helping you maintain a clean, engaged list.
How do I map form fields to my Mailchimp Audience?
Inside the Mailchimp action settings, use the merge tag dropdowns to match each form field to the corresponding Mailchimp Audience field. Custom Audience fields you have created in Mailchimp will appear after you resync the Audience list in the action settings.
Can I use Mailchimp Interest Groups and tags with this plugin?
Yes. Tags and Interest Groups you have created in your Mailchimp account will appear in the action settings. Enter tags as a comma-separated list. Toggle on the Interest Groups you want subscribers added to. Tags must match exactly, including capitalization, as they are case sensitive.
My Mailchimp Audience list is not showing up in Ninja Forms. How do I fix this?
Click the refresh icon next to the List label in the Mailchimp action settings. This re-fetches your Audiences from the Mailchimp API. If lists still do not appear, confirm your API key is correct and that it has been saved in Ninja Forms settings.
Is the Mailchimp add-on included in a Ninja Forms membership?
Yes. The Mailchimp add-on is included with any Ninja Forms membership plan. It is also available as a standalone purchase if you only need this specific integration.
Why are form submissions not being added to my Mailchimp list?
The most common cause is an unmapped required field. If a field is marked as required in your Mailchimp Audience, it must be mapped to a corresponding form field in Ninja Forms. Without that mapping, Mailchimp will reject the submission and the contact will not be added.
Changelog
3.3.7 (January 19, 2026)
Bug Fixes:
- fix jsonSerialize deprecation notice
- fix dynamic property deprecation notice
- fix call to function on null
Other:
- update plugin information
3.3.6 (9 March 2023)
Other:
- Correct plugin folder name to ensure match with existing
3.3.6 (9 March 2023)
*Other:*
– Correct plugin folder name to ensure match with existing
3.3.5 (8 February 2023)
Other:
- Improve logging to provide exception details
- Enhance automated testing
3.3.4 (25 January 2023)
- Check for optin field before creating subscriber
- Enables the creation of new tags with a form submission
- Ensure action settings interest group selection is set
- Display metabox with communication results on new Submissions page
3.3.3 (17 January 2023)
- Enable address field structure
- Prevent shared library conflicts with internalized library
- Prevent blank fields overwriting existing data
- Remove `mixed` type declaration error in PHP <8.0
3.3.2 (10 August 2022)
Error in tag prevented scheduled release
3.3.1 (25 October 2021)
- prevent PHP 8 return type error in library file
3.3.0 (11 October 2021)
- prevent PHP 8 return type error
- ensure tag type \’saved\’ is recognized
- ensure radio option in MC translates in autogenerator
- ensure duplicated forms don\’t carry \’ghost\’ pre-selected interests that cannot be removed
3.2.2 (December 2020)
- Fix type hint mismatch error
- Fix WP_Error code string causing exception
3.2.1 (November 2020)
- Add autogenerator popup modal functionality with coordinated change in Ninja Forms core
3.2.0 (October 2020)
- Add support for Mailchimp Tags, user-selected Merge Fields
- Add Mailchimp automatic form generator that builds form from Audience for you
- Add per-submission diagnostics
- Add automatic form generator
3.1.11 (12 June 2019)
- Timeout errors should no longer occur as frequently when validating API keys.
3.1.10 (15 May 2019)
- An error should now be thrown if cUrl is not installed on the site.
3.1.9 (27 November 2018)
- Resolved an issue that was causing the plugin to always appear as if an update was available.
3.1.8 (1 November 2018)
- Added check to catch fatal errors if the API response is malformed.
3.1.7 (10 May 2018)
- Resolved an error that sometimes occurred if only a single merge field was mapped to a form.
3.1.6 (17 April 2018)
- Updating existing subscribers should no longer remove non-included information from their records.
- Added a new form template for basic MailChimp signup.
3.1.5 (26 March 2018)
- Resolved an issue that was sometimes causing data to not be sent to MailChimp.
3.1.4 (12 March 2018)
- Resolved an issue that sometimes caused a fatal error to be thrown when a bad API key was entered on the settings page.
- List fields and interest groups will now pull in more values if they are available. (Up to a maximum of 100, as allowed by the MailChimp API.)
3.1.3 (21 February 2018)
- Pre-existing users who subscribe to a new list should now be updated properly.
3.1.2 (8 February 2018)
- Fixed an issue that was causing the API to only import a maximum of 10 lists.
3.1.1 (6 February 2018)
- Resolved an issue that sometimes caused interest groups to not be sent to MailChimp.
3.1.0 (5 February 2018)
- MailChimp API version has been updated to 3.0.
- SSL Verify Peer setting is no longer necessary and has been removed.
- MailChimp actions malfunctioning as a result of removing lists/groups from MailChimp can now be fixed by refreshing list data in the MailChimp action.
3.0.5 (30 December 2017)
- Raised the maximum number of lists that can be imported from 25 to 100.
3.0.4 (21 June 2017)
- Fixed a bug that caused MailChimp to fail when using other MailChimp plugins.
- MailChimp actions should now fire after Collect Payment actions.
3.0.3 (31 October 2016 )
- Fixed a possible fatal error when saving incorrect API Keys.
3.0.2 (11 April 2016 )
- Compatibility with Ninja Forms Three.
3.0.1 (11 April 2016 )
- Fix an issue with licensing and automatic updates.
3.0 (7 March 2016 )
- Updated with Ninja Forms v3.x compatibility
- Deprecated Ninja Forms v2.9.x compatible code
1.3.4 (3 August 2015 )
- Fixed an undefined index when a list does not have any groups
- Fixed an error when a list does not have any groups
1.3.3 (27 July 2015 )
- Fixed a fatal error when Ninja Forms core is deactivated.
= 1.3.2 (27 May 2015)
- Fix fatal error when list has no interest groupings
= 1.3.1 (27 May 2015)
- Fix fatal error due to undefined class
= 1.3 (26 May 2015)
- Moved MailChimp integration options to Emails and Actions API
- Added support for multiple MailChimp subscriptions per form
- Added support for mapping form fields to merge fields in MailChimp
- Added support for MailChimp groups
= 1.2.1 (20 April 2015)
* Fixed invalid API key check when saving form settings
= 1.2 (16 April 2015)
- Added an option to disable SSL verification
- Improved error message when an API key is invalid
= 1.1.3 (7 February 2015)
- Cached the lists data in a transient
- Updated the settings field description to provide a sample API key
- Added API key validation to the save function to ensure a valid key is entered
1.1 (19 September 2014)
- Updated the MailChimp API
- Added support for tracking Zip/Postal Code, Phone, and IP for subscribers
1.0.3 (20 August 2014)
- Moved processing to the ninja_forms_post_process hook.