Krom Automation Pro connects to MailerLite, giving you four actions to manage subscribers and groups automatically based on WordPress events. Subscribe new users to your lists, move them between groups as they progress through your site, and remove them cleanly when they opt out or cancel.

An API key is required. No OAuth setup needed.

Requirements #

• Krom Automation Pro installed and activated
• A MailerLite account
• A MailerLite API key

Configuration #

1. Log in to your MailerLite account.
2. Go to Integrations > Developer API.
3. Click Generate new token, give it a name like Krom Automation, and copy the token.
4. In your WordPress admin, go to Krom Automation > Settings.
5. Find the MailerLite settings section and paste your API key into the API Key field.
6. Click Save.

Screenshot: MailerLite Integrations page showing the Developer API section with the Generate new token button.

Screenshot: Krom Automation Settings page with the MailerLite API Key field filled in.

Available actions #

Subscribe

Adds a subscriber to MailerLite or updates their record if they already exist (matched by email address). This is an upsert — safe to use on contacts who may already be in your MailerLite account.

Field	Required	Description
email	Yes	The subscriber’s email address. Use the appropriate merge tag from your trigger.
name	No	Subscriber’s name. MailerLite uses a single name field rather than separate first and last name fields.
fields	No	Any additional subscriber fields you’ve defined in MailerLite, such as phone number or custom data fields.

Common use: Adding new WordPress user registrations to your main MailerLite subscriber list, or adding WooCommerce customers as subscribers after their first purchase.

Unsubscribe

Marks a subscriber as unsubscribed in MailerLite. The contact record is retained but they will no longer receive campaigns.

Field	Required	Description
email	Yes	The subscriber’s email address.

Common use: Unsubscribing a customer from your MailerLite list when their WooCommerce Subscription is cancelled, a MemberPress membership expires, or a user deletes their WordPress account.

Add to Group

Adds a subscriber to a specific MailerLite group. In MailerLite, groups are used to segment subscribers for targeted campaigns and automations.

Field	Required	Description
email	Yes	The subscriber’s email address.
group_id	Yes	The MailerLite group ID. Find this in MailerLite under Subscribers > Groups — click a group and look at the URL or group settings for the ID.

Common use: Adding a subscriber to a “customers” group after a WooCommerce purchase, or placing a new course enrollee in a “students” group for targeted email campaigns.

Remove from Group

Removes a subscriber from a MailerLite group without unsubscribing them from your overall list.

Field	Required	Description
email	Yes	The subscriber’s email address.
group_id	Yes	The MailerLite group ID to remove them from.

Common use: Removing a subscriber from an “active trial” group when their trial converts to a paid plan, or moving them out of a “new subscriber” group after they’ve completed onboarding.

Setting up your first MailerLite workflow #

1. Go to Krom Automation > Workflows and click Add New Workflow.
2. Choose your trigger. Common triggers for MailerLite workflows include User Registered, WooCommerce Order Completed, Ninja Forms Form Submitted, and WooCommerce Subscriptions Subscription Cancelled.
3. Click + and add a MailerLite action.
4. Enter the email merge tag, any name field, and the group ID if needed.
5. Simulate to confirm everything resolves correctly.
6. Activate.

Screenshot: Krom Automation canvas with a User Registered trigger connected to a MailerLite Subscribe action with the email and name fields configured.

Finding your MailerLite group ID #

In MailerLite, go to Subscribers > Groups. Click on the group you want to use. The group ID appears in the browser URL — for example, app.mailerlite.com/subscribers/groups/1234567. The number at the end is your group ID.

Real-world automation examples #

Subscribe new WordPress users Trigger: User Registered Action: MailerLite Subscribe using {{user_email}} and {{display_name}} as the name field.

Add WooCommerce customers to a customers group Trigger: WooCommerce Order Completed Action 1: MailerLite Subscribe using {{customer.email}} and {{customer.first_name}} Action 2: MailerLite Add to Group using {{customer.email}} and your customers group ID.

Subscribe Ninja Forms submitters to a lead nurture group Trigger: Ninja Forms Form Submitted (filtered by form_id) Action 1: MailerLite Subscribe using the email field merge tag from the form Action 2: MailerLite Add to Group placing them in your lead nurture group.

Remove from active group on subscription cancellation Trigger: WooCommerce Subscriptions Subscription Cancelled Action 1: MailerLite Remove from Group removing them from your active subscribers group Action 2: MailerLite Add to Group adding them to a churned or win-back group.

Pre-built templates #

Install these from Krom Automation > Templates:

Template	What it does
ml-user-registration-subscribe	Subscribes new WordPress users to MailerLite
ml-woo-purchase-subscribe	Subscribes WooCommerce customers to MailerLite on purchase

Troubleshooting on MailerLite integration #

The Subscribe action is failing

Check the execution log for the error detail. Common causes are an invalid or expired API key, or an email address that MailerLite has blocked due to bounces or spam complaints. MailerLite does not allow re-subscribing contacts that have been permanently unsubscribed.

I can’t find my group ID

Go to Subscribers > Groups in MailerLite, click the group, and look at the browser URL. The numeric ID in the URL is what you need. Alternatively, check the group’s settings page where the ID may also be displayed.

Subscribers are being added but not appearing in the group

Check that the Subscribe action runs before the Add to Group action in your workflow. If the contact doesn’t exist in MailerLite yet, adding them to a group in the same step may fail. Order the actions so Subscribe runs first, followed by Add to Group.