MailerLite API Authentication

How to authenticate MailerLite API requests: one Bearer API key plus a connectionId. MindCloud stores your API key securely — set it once, never resend it.

Every MailerLite API request through MindCloud needs two things: a MindCloud API Key and a connectionId for your MailerLite account. This page covers both, plus exactly how to send them, so you do not need to visit any other page to get authenticated.

Steps to authenticate

Create a MindCloud account at app.mindcloud.co if you do not already have one.
Generate a MindCloud API Key in API Keys. This is the Bearer token you send on every request. Keep it on your server.
Create a MailerLite connection in Connections. MailerLite uses an API key. You generate the key in your MailerLite account, then paste it in when you create the connection — MindCloud stores it securely and never returns it in a response.
Copy the connection’s connectionId — you will send it on every request alongside your MindCloud API Key.

How requests are authenticated

Authentication has two layers. Your MindCloud API Key authenticates the request to MindCloud, sent as a Bearer token in the Authorization header. The connectionId selects the connected MailerLite account that should run the action. MindCloud stores and refreshes the MailerLite credentials behind that connection, so you never send provider tokens with your requests.

Pass connectionId in the query string for GET and DELETE actions, and in the JSON body for POST, PUT, and PATCH actions.

For example, calling List Subscribers with an MailerLite connection looks like this:

curl --request GET \
  --url "https://connect.mindcloud.co/v1/universal/mailerLite/latest/actions/list-subscribers" \
  --header "Authorization: Bearer $MINDCLOUD_API_KEY" \
  --get \
  --data-urlencode "connectionId=$CONNECTION_ID"

The Authorization: Bearer <your MindCloud API Key> header authenticates you to MindCloud; the connectionId tells MindCloud which MailerLite account to run the action against. Missing or invalid Authorization returns 401, and a missing or mismatched connectionId returns 400.

Create a MailerLite API token

MailerLite API keys are server-side credentials for machine-to-machine authentication. If you lose the token after creation, you must generate a new one.

Open the MailerLite API integration page
Sign in to MailerLite, go to Integrations from the left sidebar, and open MailerLite API.
Integrations → MailerLite API
Generate a new token
Click Generate new token, give the token a recognizable name, and decide whether to allow any IP address or restrict the token to specific trusted IPs.
Copy the token immediately
Copy the generated API token or download it as a TXT file and store it somewhere secure. MailerLite cannot show the full token again later.
Paste the token into MindCloud
Return to the MindCloud MailerLite connection form and paste the copied token into the API key field.

Keep your key safe

Keep your MindCloud API Key on your server; do not ship it in browser code, mobile apps, public repositories, or logs. Anyone with the key can call the Universal API as your MindCloud account, across every connection you have created.