# How to Sync GrowSurf Referral Data to MailerLite Subscribers

> Connect MailerLite Classic to GrowSurf, pick a Group, and sync 15 referral fields onto every subscriber automatically.

- URL: https://growsurf.com/integration-guides/mailerlite-referral-subscriber-sync/

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[← View All Guides](/integration-guides/)

One API key, one Group, 15 referral fields — on MailerLite Classic, which is the part to check first.

Want the full setup walkthrough?

Use these docs for exact setup steps, supported fields, and troubleshooting.

[GrowSurf MailerLite setup guide](https://docs.growsurf.com/integrations/mailerlite) [MailerLite custom fields help](https://www.mailerlite.com/help/how-to-create-and-use-custom-fields)

GrowSurf adds and updates subscribers in the MailerLite Group you choose and creates the fields holding each participant’s referral link, referral counts, referrer details, and milestone progress.

This integration works with **MailerLite Classic**. If your account is on MailerLite New, the direct integration does not apply — you can still connect the two through Zapier or Webhooks. Check which one you are on before you start.

## Integration Steps

### Confirm you are on MailerLite Classic

GrowSurf’s MailerLite integration supports MailerLite Classic. On MailerLite New, use [Zapier](/integration-guides/zapier-referral-automation-workflows/) or [Webhooks](/integration-guides/webhooks-custom-reward-fulfillment/) instead. The integration card in GrowSurf states this too, so you will not get far down the wrong path.

### Get your MailerLite API key

Copy your API key from [MailerLite > Integrations > API](https://app.mailerlite.com/integrations/api/).

### Connect MailerLite in GrowSurf

Open **Program Editor > 4. Options > Integrations** and search for MailerLite.

Searching for MailerLite in the GrowSurf Program Editor integrations listSearch the integrations list in Program Editor > 4. Options > Integrations.

Expand the card, paste the API key, and submit.

The MailerLite API key field in GrowSurf, with a note that only MailerLite Classic is supportedThe card states the MailerLite Classic requirement before you paste a key.

Connect before importing participants; the sync covers people added from that point on. Already imported? Use the [existing-participant sync options](https://support.growsurf.com/article/385-how-can-i-sync-my-growsurf-participants-to-my-esp).

### Choose the Group and save

MailerLite organizes by Group. Pick the one that should receive GrowSurf participants and save changes.

### Know your fields

| GrowSurf data | Variable | Type | What it holds |
| --- | --- | --- | --- |
| Share URL | {$grsf_share_url} | Text | The participant’s unique referral link |
| Participant ID | {$grsf_participant_id} | Text | The participant’s GrowSurf ID |
| Referral Status | {$grsf_participant_referral_status} | Text | CREDIT_PENDING, CREDIT_AWARDED, or CREDIT_EXPIRED |
| Participant first name | {$grsf_participant_first_name} | Text | The participant’s first name |
| Participant last name | {$grsf_participant_last_name} | Text | The participant’s last name |
| Referrer first name | {$grsf_referrer_first_name} | Text | The referrer’s first name, when there is one |
| Referrer last name | {$grsf_referrer_last_name} | Text | The referrer’s last name, when there is one |
| Referrer email | {$grsf_referrer_email} | Text | The referrer’s email, when there is one |
| Total referral count | {$grsf_total_referral_count} | Number | All-time referral count |
| Monthly referral count | {$grsf_monthly_referral_count} | Number | Referral count for the current month |
| Previous monthly referral count | {$grsf_prev_monthly_referral_count} | Number | Referral count for the previous month |
| Next milestone | {$grsf_next_milestone} | Text | The next milestone message, on programs with milestone rewards |
| Next monthly milestone | {$grsf_next_monthly_milestone} | Text | The next monthly milestone message, when there is one |
| Total invite count | {$grsf_total_invite_count} | Number | All-time invite count |
| Total impression count | {$grsf_total_impression_count} | Number | All-time referral-link view count |

MailerLite variables use `{$name}`. Use them exactly as shown in campaign content.

## Tips

#### Classic or nothing

This is the first thing to verify. A MailerLite New account cannot use the direct integration no matter how the key is configured.

#### Group, not list

MailerLite calls it a Group. GrowSurf writes subscribers into the one you select.

#### The dollar sign is part of the syntax

`{$grsf_share_url}` resolves; the same name without `$` does not.

Recommended Guides

[MailerLite logo How to Add Referral Links to MailerLite Campaigns MailerLite variables put each subscriber’s own referral link into a single campaign or automation. View Guide →](/integration-guides/mailerlite-referral-email-personalization/) [EmailOctopus logo How to Sync GrowSurf Referral Data to EmailOctopus One API key, one list, and every contact carries their referral link as a custom field. View Guide →](/integration-guides/emailoctopus-referral-contact-sync/) [AWeber logo How to Sync GrowSurf Referral Data to AWeber Subscribers Connect AWeber, pick a list, and every subscriber carries their own referral link and progress as custom fields. View Guide →](/integration-guides/aweber-referral-subscriber-sync/)

## FAQ

#### Does this work with MailerLite New?

No. The direct integration supports MailerLite Classic. For MailerLite New, connect through Zapier or Webhooks.

#### Where do I get the API key?

MailerLite > Integrations > API.

#### What is the variable for the referral link?

`{$grsf_share_url}`.

## Turn word of mouth into steady growth from your customers

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