Campaign Monitor

Datafly Signal syncs identified contacts into Campaign Monitor server-to-server using the Subscriber Management API. When a visitor signs up, logs in, or submits a form, Signal upserts them as a subscriber on your chosen list — with email, name, mobile, tracking consent, and custom fields — so they enter your lists, automations, and journeys without any client-side script.

Prerequisites

Before configuring Campaign Monitor in Signal, you need a Campaign Monitor account, an API key, and the ID of the subscriber list you want to sync contacts into.

Step 1: Get your API key

1. Log in to Campaign Monitor.
2. Go to Account settings (top-right menu) > API key.
3. Click Show API key and copy it.

The API key is used as the HTTP Basic username; the password is not used.

Step 2: Find your List ID

1. Go to Lists & subscribers and open the list you want to sync into.
2. Open the list Settings (Change name/type).
3. Copy the List API ID — a long alphanumeric string.

Step 3: Create your custom fields (if used)

Campaign Monitor only accepts custom data through fields that already exist on the list. If your blueprint maps custom fields (for example company or signup_method):

1. In the list, go to Custom fields.
2. Click Create custom field and add each field key your blueprint uses.

Configure in Signal

Configuration Fields

Management UI Setup

1. Go to Integrations > Add Integration > Campaign Monitor.
2. Choose the Default preset (contact sync).
3. Enter your api_key and list_id.
4. Select the consent category that governs email tracking (typically marketing).
5. Click Save.

API Endpoint

POST https://api.createsend.com/api/v3.3/subscribers/{list_id}.json
Authorization: Basic base64("{api_key}:")
Content-Type: application/json

The API key is the Basic-auth username; the password is left empty. A successful upsert returns 201 Created with the subscriber’s email address in the body. POSTing an email that already exists updates that subscriber.

Identity Signals

Campaign Monitor keys subscribers on email address. Signal populates the subscriber record from the traits supplied via datafly.identify():

Consent

Signal maps your canonical marketing consent to Campaign Monitor’s ConsentToTrack field:

ConsentToTrack controls whether Campaign Monitor may track the subscriber’s email opens and link clicks.

How to Send User Data

Call datafly.identify() when a user registers, logs in, or submits a form:

datafly.identify("user-123", {
  email: "jane.doe@example.com",
  name: "Jane Doe",
  phone: "+44 7700 900123",
  company: "Acme Ltd"
});

Event Mapping

Only identity events upsert a subscriber. Each maps to a single POST /subscribers/{list_id}.json call.

Default preset

All other events (page, Product Viewed, Order Completed, …) are dropped, because Campaign Monitor cannot consume them.

To customise which traits map to which custom fields, edit the integration’s Field Mappings in the Management UI.

Example: Sign-up event

Datafly.js call:

datafly.identify("user-123", {
  email: "jane.doe@example.com",
  name: "Jane Doe",
  phone: "+44 7700 900123"
});
 
datafly.track("Signed Up", {
  method: "email"
});

Campaign Monitor payload sent by Signal:

{
  "EmailAddress": "jane.doe@example.com",
  "Name": "Jane Doe",
  "MobileNumber": "+447700900123",
  "ConsentToTrack": "Yes",
  "Resubscribe": true,
  "CustomFields": [
    { "Key": "datafly_anonymous_id", "Value": "a1b2c3d4-..." },
    { "Key": "signup_method", "Value": "email" }
  ]
}

Testing

Troubleshooting

Rate Limits

Campaign Monitor rate-limits the API and returns X-RateLimit-Limit, X-RateLimit-Remaining, and X-RateLimit-Reset headers, but does not publish a fixed requests-per-second figure for the subscriber endpoints. Signal applies a conservative sustained rate with a small burst and backs off automatically on 429 responses.