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First-party app
MailerLite

MailerLite

Manage MailerLite subscribers, groups, fields, segments, and email campaigns.

stable MarketingEmail

About

MailerLite ships in the w6w first-party pack. It declares 16 actions, 2 health checks, and the host runs its code in a sandbox that never sees the credential.

App id
io.w6w.mailerlite
Version
0.1.3
Author
w6w
Licence
MIT
Categories
Marketing · Email

Overview

MailerLite manages email subscribers and the campaigns sent to them, and this app covers both sides. Add, update or upsert subscribers, assign or remove them from groups, and read the custom fields and segments that make targeting possible. Group membership added through an upsert is additive, while setting it explicitly through an update replaces it outright — the app follows MailerLite’s own distinction rather than picking one behavior for both.

Campaigns can be created and scheduled to send, staying in draft until scheduling is explicitly triggered — nothing goes out by accident. Listing groups, fields and segments feeds directly into the write actions, since MailerLite’s API expects subscribers tagged with those exact names and ids.

Good for syncing subscriber data from a signup form or CRM, triggering a campaign send from an external event, or keeping group membership current as people move through a workflow. Built against MailerLite’s current API, not the older Classic API some integrations still target.

Build with MailerLite

Three routes to the same 16 actions. The Workflow tab is generated from MailerLite's own manifest and carries its real ids, so it is copy-pasteable; the Code and CLI examples are the same call for any action on any app, so every app-specific value in them is a blank you fill in.

Assign Subscriber to Group

assign-subscriber-to-group

Add an existing subscriber to an existing group.

Create Campaign

create-campaign

Create a draft campaign. Send it with Schedule Campaign.

Create Group

create-group

Create a subscriber group.

Delete Subscriber

delete-subscriber

Remove a subscriber from the account by id. Their history is retained.

Get Campaign

get-campaign

Fetch a single campaign, including its emails, filter and delivery schedule.

Get Subscriber

get-subscriber

Fetch a single subscriber by id or email address.

List Campaigns

list-campaigns

List campaigns. MailerLite defaults to status `ready` when no status filter is supplied.

List Fields

list-fields

List the subscriber fields defined on the account, with their keys and types.

List Group Subscribers

list-group-subscribers

List the subscribers in a group. Pass `meta.next_cursor` back as `cursor`.

List Groups

list-groups

List groups with their subscriber counts and engagement stats.

List Segments

list-segments

List the account's segments with their subscriber counts and engagement stats.

List Subscribers

list-subscribers

List subscribers. Walks one page — pass `meta.next_cursor` back as `cursor`.

Schedule Campaign

schedule-campaign

Send a draft campaign now, or schedule it for a future date and time.

Unassign Subscriber from Group

unassign-subscriber-from-group

Remove a subscriber from a group. The subscriber itself is not deleted.

Update Subscriber

update-subscriber

Update a subscriber by id. Supplying `groups` REPLACES membership — unlisted groups are removed.

Create or Update Subscriber

upsert-subscriber

Create the subscriber if the email is new, otherwise merge the values in. Never removes fields or groups.

A workflow step names the app and the action, and the editor fills in the connection when you pick one. This is the Step shape from the workflow spec, carrying MailerLite's real ids. 

{
  "manifestVersion": "2",
  "name": "mailerlite-example",
  "steps": [
    {
      "id": "assign-subscriber-to-group",
      "uses": {
        "app": "io.w6w.mailerlite",
        "action": "assign-subscriber-to-group",
        "connection": "conn_YOUR_CONNECTION_ID"
      },
      "with": {
        "subscriberId": "<subscriberId>",
        "groupId": "<groupId>"
      }
    }
  ]
}

Here are some of the things you can do

  • Assign Subscriber to Group

    perform
    assign-subscriber-to-group

  • Create Campaign

    perform
    create-campaign

  • Create Group

    perform
    create-group

  • Get Campaign

    read
    get-campaign

  • Get Subscriber

    read
    get-subscriber

+11 more actions available

Every app-specific value here is a blank you have to fill in. An app action is reached through the connection that authenticates it, so the address is a connection id, not the app id — and connections belong to your account, so a public page cannot know yours. Create one for MailerLite, then fill in the three blanks: conn_YOUR_CONNECTION_ID, the action key, and the parameters that action declares. The call itself is real — the shape is transcribed from the studio's own snippet builder, which prints the same kind of blanks — but nothing in it is specific to MailerLite. The Workflow tab is where this app's real ids are.

Install 
npm install @w6w/sdk
yarn add @w6w/sdk
pnpm add @w6w/sdk
deno add npm:@w6w/sdk
Code 
import { W6wClient, isActionRun } from "@w6w/sdk";

// Reads W6W_BASE_URL and W6W_TOKEN from the environment when omitted.
const client = new W6wClient();

const envelope = await client.run({
  urn: "conn_YOUR_CONNECTION_ID",
  action: "upsert-subscriber",
  payload: {
    email: "<value>",
    // fields: "<value>",
    // groups: "<value>",
    // status: "<value>",
    // subscribedAt: "<value>",
    // ipAddress: "<value>",
    // resubscribe: "<value>",
  },
});

if (isActionRun(envelope)) console.log(envelope.value);
Install the CLI 
npm install -g @w6w/cli
CLI 
w6w run conn_YOUR_CONNECTION_ID --action upsert-subscriber --payload '{"email":"<value>"}'

Give an AI agent MailerLite — without giving it MailerLite's credentials. One MCP endpoint exposes every app, function and workflow the caller is entitled to, as tools it can discover and run. Access is granted per team while we onboard.

One tool call 
{
  "name": "w6w_invoke",
  "arguments": {
    "ref": "app:io.w6w.mailerlite#assign-subscriber-to-group",
    "input": {
      "subscriberId": "<subscriberId>",
      "groupId": "<groupId>"
    }
  }
}

Every tool names its target with a single ref. The app: form above doesn't name a connection at all — the host resolves which of the caller's MailerLite connections to sign with, and refuses rather than guesses when the answer is ambiguous.

What the agent gets

Credentials it can't read

The token is attached host-side, at the moment of the call. It is never a tool argument, never in the model's context, and never in a transcript — so a prompt injection has nothing to exfiltrate.

A tool surface scoped to the caller

Tools are derived per end user from what that person has actually connected and is entitled to — not one shared bot identity carrying the union of everyone's access.

A durable workflow in one call

Multi-step work runs on the workflow engine and returns a run handle the agent can poll — retries, branching and state survive the conversation that started them.

Health-aware discovery

MailerLite's declared health checks are on the surface too, so an agent can tell "the vendor is down" from "your credential expired" before it burns a retry on either.

The MCP surface is part of the hosted platform. MailerLite itself is MIT, and the runtime that executes it is source-available (FSL).

Request MCP access

Health checks

MailerLite declares its own checks, so its health is a property of the app rather than something the host guesses at.

service

MailerLite platform status

Statuspage-format rollup for status.mailerlite.com, with per-component detail. Unauthenticated and unsigned.

quota

API rate-limit headroom

Requests remaining on this credential, read off the `X-RateLimit-*` headers. MailerLite documents them only on a 429, so a healthy response often carries none.