Connect forms to MailerLite with Make: add subscribers without duplicates

Our verdict: one upsert module, one consent check, one test

For most small lists, the right scenario is short: a form sends a webhook to Make, a filter checks that the consent box was ticked, and MailerLite's Create/Update a Subscriber module adds or updates the person. Make's MailerLite app lists that module alongside Add Subscriber to a Group, Get a Subscriber and Watch Subscriber Events [1]. You do not need a search step first, because the update behaviour is built into the call.

We have not run this scenario. The behaviour described here comes from Make's app documentation and MailerLite's API reference, which describes the endpoint Make's module is named after. Run the test cases at the end of this guide with your own address before pointing a live form at it.

Pick the right MailerLite app and connect it

Make documents two separate apps. MailerLite Classic supports only API v1, and its token is created under Integrations, Developer API [2]. The newer MailerLite app asks you to generate a new API token, name it and paste it into the API Key field in Make [1]. MailerLite's API documentation says keys are sent as a bearer token [3], so treat the token like a password: store it only in the Make connection, never in a sheet or a scenario note.

Some official Make templates still use MailerLite Classic; for example, the Facebook Lead Ads to MailerLite and HubSpot template lists MailerLite Classic as its app [4]. If your account is on the newer MailerLite, swap those modules before running the template.

Why Create/Update avoids duplicates, and what it can overwrite

MailerLite's subscriber endpoint is an upsert. Its documentation says: if a subscriber already exists, it will be updated with new values [5]. It returns 201 when a new subscriber is created and 200 when an existing one is updated [5]. Fields you leave out are not changed, and the groups array only adds memberships; omitting groups does not remove existing ones [5].

That last point is the real risk. If a returning visitor submits the form with a blank company field and you map that blank into MailerLite, you may replace a good value with an empty one, depending on how the module treats empty values. Add a Make filter or use an if-empty fallback so you only send fields that contain data. Keep email addresses lowercase and trimmed before mapping; it costs nothing extra because it is a function inside the mapping, not a separate module.

Map fields and consent deliberately

MailerLite's API accepts a status for the subscriber (active, unsubscribed, unconfirmed, bounced or junk), consent timestamps (subscribed_at and opted_in_at in yyyy-MM-dd HH:mm:ss format) and IP addresses (ip_address and optin_ip) [5]. If your form records when and from which IP the person ticked the consent box, map those values; they are the record you will want if someone later asks how they were added.

MailerLite's import guidance is blunt: be sure every subscriber added to your account has given consent to receive marketing emails [6]. The same principle applies to automated adds. Put the consent checkbox in the form, send its value in the webhook, and add a filter so only submissions with consent reach the MailerLite module. If you use double opt-in, send new people with the unconfirmed status and let your confirmation process do the rest; our opt-in guide compares the two approaches.

Credits per new subscriber and per month

Make's operations page counts one operation per module run per bundle, and a trigger once per check [7]. Its billing FAQ says most actions consume 1 credit and that routers and error handlers do not consume credits [8]. With a webhook trigger, the scenario only runs when the form is submitted.

Worked example (assumptions labeled): 250 form submissions a month, 20 of them without consent. Webhook: 250 credits. Create/Update: 230 credits. Total about 480 credits, within the Free plan's 1,000 monthly credits [8] if nothing else runs on the account. Adding a separate Add Subscriber to a Group step would add another 230. If you replace the webhook with a scheduled check of a form app every hour, add 720 credits a month for the checks alone.

MailerLite's own limits matter too: its pricing page lists the Free plan at 250 subscribers and 2,500 monthly emails, with paid Comfort plans starting at $12 per month [9]. The API has a global rate limit of 120 requests per minute [3], which only matters if you bulk-load an old list through Make.

Test cases before going live

• New address with consent: expect a new subscriber (MailerLite returns 201) in the right group.
• Same address again with a changed name: expect one record with the new name (200), not a second subscriber.
• Same address with a blank optional field: confirm the existing value was not erased.
• Submission without consent: expect the run to stop at the filter and nothing to reach MailerLite.
• An address that previously unsubscribed: confirm the scenario does not resubscribe them; MailerLite only does that when resubscribe is set to true [5].
• Invalid email: expect a 422 validation error [5]; add an error handler that logs it rather than retrying forever.

Sources & verification

Product details and prices can change. Check the linked provider before buying.

1. Make apps documentation: MailerLite Accessed 29 Oct 2026
2. Make apps documentation: MailerLite Classic Accessed 29 Oct 2026
3. MailerLite API documentation: authentication and rate limits Accessed 29 Oct 2026
4. Make template: Facebook Lead Ads lead to MailerLite and HubSpot CRM Accessed 29 Oct 2026
5. MailerLite API: Subscribers (create/upsert) Accessed 29 Oct 2026
6. MailerLite Help: How to import subscribers Accessed 29 Oct 2026
7. Make Help Center: Operations Accessed 29 Oct 2026
8. Make pricing and billing FAQ Accessed 29 Oct 2026
9. MailerLite pricing Accessed 29 Oct 2026