MailerLite

Introduction

The MailerLite integration adds your paying customers to MailerLite when payment events occur. It can add customers to groups, store payment data in subscriber fields, and start automation workflows, so your email lists reflect real payment activity. MailerLite is an email marketing platform for newsletters, campaigns, and automations. Use this integration to manage subscribers based on payment activity, for onboarding sequences, customer segmentation, and targeted campaigns.

This integration authenticates with a MailerLite API key. To create one, open your MailerLite Integrations page and click Generate new token.

Getting Started

Open the Webhook Section

In the Dodo Payments dashboard, go to Developer → Webhooks and click Add endpoint.

Add endpoint dialog with MailerLite selected in the Integration dropdown

Select MailerLite

In the Integration list, select MailerLite.

Enter API Key

Paste your MailerLite API key into the API key field. Dodo Payments sends it as an Authorization header on every delivery.

Configure Transformation

Edit the code under Transformation code so each event becomes a MailerLite subscriber request. Start from the examples below.

Test & Create

Under Test this code, run the transformation against a sample payload, then click Create endpoint.

Done

Payment events now add and update subscribers in your MailerLite groups.

Transformation Code Examples

Most examples send a POST request to the MailerLite subscribers API. MailerLite creates the subscriber, or updates the existing subscriber with the same email address. This upsert never removes fields or groups that you leave out.

Add Customer on Successful Payment

This example adds the customer to one group when a payment succeeds. Replace your-group-id-here with a MailerLite group ID.

add_customer.js

function handler(webhook) {
  if (webhook.eventType === "payment.succeeded") {
    const p = webhook.payload.data;
    webhook.url = "https://connect.mailerlite.com/api/subscribers";
    webhook.payload = {
      email: p.customer.email,
      fields: {
        name: p.customer.name,
        last_name: ""
      },
      groups: ["your-group-id-here"],
      status: "active"
    };
  }
  return webhook;
}

Add Subscriber to Multiple Groups Based on Product

This example adds every paying customer to a customers group, and adds customers who pay $100 or more to a premium group as well.

product_segmentation.js

function handler(webhook) {
  if (webhook.eventType === "payment.succeeded") {
    const p = webhook.payload.data;
    
    // Determine groups based on product or amount
    const groups = ["customers-group-id"];
    
    // Add to premium group if high-value purchase
    if (p.total_amount >= 10000) { // $100+
      groups.push("premium-customers-group-id");
    }
    
    webhook.url = "https://connect.mailerlite.com/api/subscribers";
    webhook.payload = {
      email: p.customer.email,
      fields: {
        name: p.customer.name,
        last_purchase_amount: (p.total_amount / 100).toFixed(2),
        last_purchase_date: new Date(webhook.payload.timestamp).toISOString().split('T')[0],
        payment_id: p.payment_id
      },
      groups: groups,
      status: "active"
    };
  }
  return webhook;
}

Add New Subscriber on Subscription Activation

This example adds the customer to two subscriber groups and stores the plan details when a subscription becomes active.

subscription_subscriber.js

function handler(webhook) {
  if (webhook.eventType === "subscription.active") {
    const s = webhook.payload.data;
    webhook.url = "https://connect.mailerlite.com/api/subscribers";
    webhook.payload = {
      email: s.customer.email,
      fields: {
        name: s.customer.name,
        subscription_plan: s.product_id,
        subscription_amount: (s.recurring_pre_tax_amount / 100).toFixed(2),
        billing_frequency: s.payment_frequency_interval,
        subscription_start: new Date().toISOString().split('T')[0]
      },
      groups: ["subscribers-group-id", "active-subscriptions-group-id"],
      status: "active"
    };
  }
  return webhook;
}

Update Subscriber on Subscription Cancellation

This example updates an existing subscriber when a subscription is cancelled. It sends a POST upsert keyed by email address, because MailerLite’s PUT update endpoint takes the MailerLite subscriber ID, which the Dodo Payments payload doesn’t contain. The upsert adds the subscriber to the churned group and keeps their other groups.

subscription_cancelled.js

function handler(webhook) {
  if (webhook.eventType === "subscription.cancelled") {
    const s = webhook.payload.data;
    // POST upserts by email; PUT needs the MailerLite subscriber ID
    webhook.url = "https://connect.mailerlite.com/api/subscribers";
    webhook.payload = {
      email: s.customer.email,
      fields: {
        subscription_status: "cancelled",
        cancellation_date: new Date().toISOString().split('T')[0]
      },
      groups: ["churned-customers-group-id"]
    };
  }
  return webhook;
}

Add Customer with Custom Fields

This example stores location, contact, and payment details in subscriber fields. Create the custom fields in MailerLite first, as described in Custom Fields Setup.

custom_fields.js

function handler(webhook) {
  if (webhook.eventType === "payment.succeeded") {
    const p = webhook.payload.data;
    webhook.url = "https://connect.mailerlite.com/api/subscribers";
    webhook.payload = {
      email: p.customer.email,
      fields: {
        name: p.customer.name,
        country: p.billing?.country || "",
        city: p.billing?.city || "",
        phone: p.customer.phone_number || "",
        // Custom fields (must be created in MailerLite first)
        total_spent: (p.total_amount / 100).toFixed(2),
        customer_since: new Date().toISOString().split('T')[0],
        payment_method: p.payment_method || "unknown",
        currency: p.currency || "USD"
      },
      groups: ["paying-customers-group-id"],
      status: "active",
      subscribed_at: new Date().toISOString().replace('T', ' ').split('.')[0]
    };
  }
  return webhook;
}

Trigger Automation via Event

This example updates a trigger field on every successful payment. Build an automation in MailerLite that starts when last_payment_trigger changes.

trigger_automation.js

function handler(webhook) {
  if (webhook.eventType === "payment.succeeded") {
    const p = webhook.payload.data;
    
    // First, ensure subscriber exists
    webhook.url = "https://connect.mailerlite.com/api/subscribers";
    webhook.payload = {
      email: p.customer.email,
      fields: {
        name: p.customer.name,
        // Add a trigger field that your automation watches
        last_payment_trigger: new Date().toISOString(),
        last_payment_amount: (p.total_amount / 100).toFixed(2)
      },
      status: "active"
    };
    
    // Tip: Create an automation in MailerLite that triggers
    // when 'last_payment_trigger' field is updated
  }
  return webhook;
}

Tips

Create custom fields in MailerLite before you use them in a transformation.
Use groups to segment customers by product, plan tier, or purchase behavior.
Set up automation workflows in MailerLite that start when a field is updated.
Send a POST request to /subscribers to upsert, which avoids duplicate subscriber errors.
Store payment metadata in custom fields to learn more about your customers.
Test with a small group before you enable the integration for all payments.

Custom Fields Setup

Create each custom field in MailerLite before a transformation writes to it:

Open your MailerLite dashboard.
Go to Subscribers → Fields.
Click Create field and add fields such as:
- total_spent (Number)
- customer_since (Date)
- subscription_plan (Text)
- payment_method (Text)
- last_payment_amount (Number)

Troubleshooting

Subscribers Not Being Added

Check that the API key is correct and active.
Check that the email address is valid under RFC 2821.
Check that each group ID is correct and exists in your account.
MailerLite doesn’t reactivate bounced or junk subscribers through the API. To resubscribe a previously unsubscribed subscriber, add resubscribe: true to the POST body.

Custom Fields Not Updating

Check that each custom field exists in MailerLite.
Check that field names match exactly. They are case-sensitive.
Check that each value matches the field type: text, number, or date.

Rate Limit Errors

The MailerLite API allows 120 requests per minute.
Use the batch endpoint when you process many subscribers.
Add a backoff strategy for high-volume scenarios.

Group Assignment Not Working

Check that group IDs are numeric strings.
Check that the groups exist in your MailerLite account.
A PUT request with groups removes the subscriber from every group it doesn’t list. A POST request only adds groups.

API Reference

The MailerLite create or upsert subscriber endpoint accepts these key parameters:

Parameter	Type	Required	Description
`email`	string	Yes	Valid email address (RFC 2821)
`fields`	object	No	Object with field name/value pairs
`fields.name`	string	No	Subscriber’s first name
`fields.last_name`	string	No	Subscriber’s last name
`fields.company`	string	No	Company name
`fields.country`	string	No	Country
`fields.city`	string	No	City
`fields.phone`	string	No	Phone number
`groups`	array	No	Array of group IDs to add the subscriber to
`status`	string	No	One of: `active`, `unsubscribed`, `unconfirmed`, `bounced`, `junk`
`subscribed_at`	string	No	Date in format `yyyy-MM-dd HH:mm:ss`
`ip_address`	string	No	Subscriber’s IP address
`resubscribe`	boolean	No	Set to `true` to resubscribe a previously unsubscribed subscriber

For the complete API documentation, see MailerLite Developers.

External Integrations

Messaging

Workflow Automation

CRM

Email

Analytics

Pricing

Introduction

Getting Started

Transformation Code Examples

Add Customer on Successful Payment

Add Subscriber to Multiple Groups Based on Product

Add New Subscriber on Subscription Activation

Update Subscriber on Subscription Cancellation

Add Customer with Custom Fields

Trigger Automation via Event

Tips

Custom Fields Setup

Troubleshooting

API Reference

​Introduction

​Getting Started

​Transformation Code Examples

​Add Customer on Successful Payment

​Add Subscriber to Multiple Groups Based on Product

​Add New Subscriber on Subscription Activation

​Update Subscriber on Subscription Cancellation

​Add Customer with Custom Fields

​Trigger Automation via Event

​Tips

​Custom Fields Setup

​Troubleshooting

​API Reference

Introduction

Getting Started

Transformation Code Examples

Add Customer on Successful Payment

Add Subscriber to Multiple Groups Based on Product

Add New Subscriber on Subscription Activation

Update Subscriber on Subscription Cancellation

Add Customer with Custom Fields

Trigger Automation via Event

Tips

Custom Fields Setup

Troubleshooting

API Reference