How to Use Unique Coupons in Mailchimp Workflows

Unique coupon codes make Mailchimp Workflows (formerly known as Customer Journeys) much more useful. Instead of sending the same welcome discount to everyone, you can give each subscriber a single-use code at the right point in the lifecycle, from a first signup to a win-back email.

The tricky part is timing. The code has to be generated and added to the subscriber's profile before Mailchimp sends the email. If the email goes first, the coupon field can be blank.

This guide shows the setup we use for reliably delivering unique codes in Mailchimp Workflows with Coupon Carrier.

How the automation works

The flow has four parts:

  1. A trigger occurs in your Mailchimp Workflow (e.g., a "tag is added").
  2. Coupon Carrier detects this trigger and instantly generates a unique code from a connected service like Shopify or WooCommerce, or picks one from a pre-imported list.
  3. The new code is immediately saved to a custom merge field on the subscriber's profile in Mailchimp.
  4. Coupon Carrier sends a "code_added" event back to Mailchimp, telling the Workflow it's safe to proceed to the next step.

Step 1: Configure Coupon Carrier

First, we'll set up a "Code Email" configuration in Coupon Carrier. This will tell our system to listen for a specific tag in Mailchimp and what to do when it finds one.

1.1 Create and trigger the configuration

In your Coupon Carrier dashboard, create a new Code Email configuration and select Mailchimp as the trigger. For the trigger event, choose "Trigger when a subscriber enters a segment or receives a tag." For this guide, we'll use the tag name add_welcome_code.

1.2 Set up the Mailchimp action

In the next step, you need to tell Coupon Carrier what to do when the trigger fires. This is the most critical part of the setup.

  • Choose Mailchimp as the sender.
  • Select the merge field where the code should be stored (e.g., COUPON).
  • Check the box to "Add an event to the subscriber..." and name the event code_added. This is the signal we'll use to tell Mailchimp the code is ready.
Animation showing the Mailchimp action setup in Coupon Carrier.

1.3 Select a code source

Finally, choose a Code List to use as the source for your codes. This can be an autogenerated list from Shopify/WooCommerce or a manual list you've imported. Save and activate your configuration.

Step 2: Build your Mailchimp Workflow

Now, let's build the Workflow in Mailchimp that will use our Coupon Carrier integration.

2.1 Add the tag action

In your Workflow, at the point where you want to send a coupon, add the "Tag / Untag" action and apply the exact tag you used in Step 1 (e.g., add_welcome_code).

2.2 Add the "Wait for trigger" step

This is the step that prevents blank codes. Immediately after the "Tag / Untag" action, add a "Wait for trigger" action. Set it to wait for the Event API and enter the exact event name you created in Coupon Carrier: code_added. This pauses the Workflow until Coupon Carrier confirms the code has been added to the subscriber.

Animation showing how to add the 'Wait for trigger' step in a Mailchimp Workflow.

2.3 Send your email

Now that the Workflow is paused, you can safely add your "Send email" action. In the Mailchimp email editor, simply insert the merge tag for your coupon field (e.g., *|COUPON|*) where you want the code to appear. When the Workflow resumes, this field will be populated with the unique code.

Pro tip: building repeating Workflows

If you're building a Workflow that needs to run multiple times for the same user (like an annual birthday offer), make sure to:

  • Enable the "Contact can re-enroll" setting in your Mailchimp Workflow.
  • Add a final "Tag / Untag" action to remove the trigger tag (e.g., remove add_welcome_code) so it can be added again in the future.
  • Enable the "Allow multiple codes to be delivered to the same email address" option in your Coupon Carrier configuration.

Your automation is complete

That's it. You can use this same tag-based method to add unique codes to any part of your customer lifecycle, from abandoned carts to VIP rewards.

Once a customer receives their code, the next step is redemption. If your offer is redeemed in-store, Coupon Carrier supports both a simple "Mark as Used" button and QR code scanning. See which validation method to use for help choosing.

Explore our full Mailchimp integration guide →