MailerLite Integration

In MailerLite, go to Integrations > MailerLite API and generate an API key. Paste it into LeadSync when adding MailerLite as a destination. LeadSync will pull every Group in your account so you can pick the destination for each lead source.

In MailerLite terminology, Group is the container that subscribers belong to and that triggers Automations when joined -- the same concept other tools call a list. Each LeadSync connection points at one Group, but you can create multiple connections for routing different lead sources to different Groups.

Yes. Use subscriber added to group as the Automation trigger -- every LeadSync-delivered lead is added to the destination Group within seconds of form submission, so the Automation starts immediately.

No. MailerLite de-duplicates subscribers by email natively, so a repeat submission updates the existing subscriber and re-adds them to the Group (re-triggering subscriber-added-to-group Automations).

Yes. Create the matching custom field in MailerLite first (Subscribers > Fields), then map it in the LeadSync field mapping screen. The value lands in the subscriber's fields object correctly keyed.

LeadSync skips it. MailerLite requires email as the primary subscriber identifier, so a lead without one cannot be added. This is rare on standard Facebook lead forms, which include email by default.

Yes. LeadSync supports MailerLite as a destination for lead forms from Facebook, Instagram, Google Ads lead form extensions, LinkedIn Lead Gen Forms, and TikTok Lead Generation. Each ad source becomes its own connection.

The integration uses MailerLite's v2 API, which is the standard for new MailerLite (the modern dashboard launched in 2021). MailerLite Classic uses a separate API surface that is being phased out -- if you are still on Classic, plan to migrate to new MailerLite for ongoing integration support.

Each LeadSync connection adds the subscriber to one Group. To land a subscriber in multiple Groups simultaneously, create multiple connections for the same lead form, each pointing at a different destination Group -- they all fire in parallel for each new lead, with no delay between them.

Yes. MailerLite's double opt-in is account-level (Subscribers > Settings) and applies to every API-added subscriber. If enabled, LeadSync-delivered subscribers receive MailerLite's confirmation email and stay unconfirmed until they click. If disabled, they are confirmed immediately and Automations fire right away.

MailerLite tracks subscriber status (active, unsubscribed, bounced, junk) and a previously unsubscribed contact stays unsubscribed when re-added via the API. LeadSync will not silently re-subscribe someone who has opted out -- the contact record is updated but the status remains unsubscribed until they manually re-subscribe through one of your MailerLite forms.

Yes. Create a custom field in MailerLite like "Lead Source" or "Page" and use the LeadSync field mapping screen to populate it from the source platform name or the Facebook Page name. For per-Page tracking, create a separate LeadSync connection per Page so each populates the field with its own value, giving you per-Page segmentation in MailerLite.