Using Impact Stack and MailChimp to deliver automated emails

Automated emails are a fantastic choice for several supporter email types.

Because they’re triggered by supporter activity and not an arbitrary calendar date, they allow you to send people the right content, at the right time in a way that’s truly personal to them and their relationship with you.

To deliver great, personalised, automated emails, you need to get your data flows working well. In this article we briefly cover how you can send data from Impact Stack to MailChimp in a way that allows you to trigger and add filters to automated emails.

The structure of a MailChimp automation

In this article we will use some MailChimp terminology. In MailChimp, an individual email broadcast is called a 'campaign'. An ‘Automation’ is a container for 'campaigns' which are triggered automatically in some way. An ‘automation’ can contain just one ‘campaign’ or many.

Each campaign then has a trigger, filters and post-send actions. Please visit the MailChimp help pages for more information. The data that’s received through the Impact Stack API can be used as triggers or filters. Here’s the main types of data you might like to use:

Type of MailChimp data that can be sent from Impact Stack
Can be used as automated email trigger? Can be used as automated email filter?
Impact Stack tags (set up as a special audience field) No Yes
Other audience fields Yes* Yes
Group membership Yes Yes

*You can use audience fields as triggers in MailChimp but the only trigger available in this instance is when the contents of the field is changed to a singular, specific value. E.g. trigger email automation when audience field ‘X’ changes to ‘yes’.

The Impact Stack tags field is a compound of many tags (see below) and therefore will not meet the ‘changes to x’ criteria as a trigger.

Other types of audience fields may be used as automation triggers if you bear this in mind. E.g. you may have an audience field of ‘marathonrunner’ which you populate with ‘yes’. The value on this field turning to ‘yes’ may be a trigger. But because this can lead to a proliferation of fields, and a more complex setup with the data integration, it’s our advice to simply avoid using audience fields as triggers, and stick to groups for triggers, and groups or tags for filters.

All three types of data have a maximum number of possible values so use them sparingly and delete ones that are no longer needed.

Getting the data into MailChimp


First, make sure you’ve set up your MailChimp account to accept Impact Stack tags.

In Impact Stack you can set a tag (or tags) for your forms in the ‘advanced settings’ section of step one of the form editor (it’s near the bottom). Keep the tag short as the MailChimp field that holds these has a maximum length of 255 characters for all of your tags together. If using more than one tag these should be separated by a comma.


When a user completes this form and they have a MailChimp subscription that’s known to Impact Stack, they will get this tag added to their ‘TAGS’ field in MailChimp.

Note: since we introduced this functionality, MailChimp have introduced their own ‘Tags’. So to avoid confusion we recommend labelling the Audience field ‘Impact Stack tags’.

User tags will get added to just one field in MailChimp, where they are separated by a comma, e.g.

“petition20 , xmasAppeal19, beeMPaction”.

Because all the values go into one field the Impact Stack tags can’t be used as an automated email trigger (because MailChimp doesn’t allow ‘contains’ queries for triggers, only for filters).


There are two main ways to add users to a MailChimp group using Impact Stack.

  1. Using tags. The simplest way is to create a MailChimp group with the exact same name as the tag you use on the form. When the users get the tag, they will automatically join this group too.
  2. Using the email opt-in field.
    • Step 1: ask the support team to enable the groups feature on your email opt-in field
    • Step 2: Click the yellow pencil to configure your email opt-in field and navigate to the ‘groups’ tab. Here you simply toggle ‘on’ whichever groups you want people to join when they complete this form.


A word of caution, if you’re using option 2 will not work if the email opt-in field is hidden with CSS or if the user chooses ‘no’. We therefore recommend only using option 2 for groups designed for brand new subscribers where they will all see and have chosen ‘yes’ on the email opt-in field. But tags will still work here, so they might be an even easier bet.

Audience fields

Please see separate help article.

Remember to test all of your settings and automations before launching a campaign!

If you have questions, feel free to reach out.

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