Postmark API Authentication

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

Every Postmark API request through MindCloud needs two things: a MindCloud API Key and a connectionId for your Postmark 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 Postmark connection in Connections. Postmark uses an API key. You generate the key in your Postmark 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 Postmark account that should run the action. MindCloud stores and refreshes the Postmark 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 Templates with an Postmark connection looks like this:

curl --request POST \
  --url "https://connect.mindcloud.co/v2/universal/apps/postmark/actions/list-templates/run" \
  --header "Authorization: Bearer $MINDCLOUD_API_KEY" \
  --header "Content-Type: application/json" \
  --data '{
  "connectionId": "$CONNECTION_ID",
  "arguments": {}
}'

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

Connect your Postmark account

You need one Server API Token and one Account API Token from the same Postmark account.

Sign in to Postmark
Open the Postmark account app and sign in with the account that owns the server you want to use.
Postmark account
Copy the Server API Token
Open the server you want to use, then open the API Tokens tab and copy a Server API Token. Use this token for server-scoped actions such as templates, messages, bounces, stats, and email sends.
Server → API Tokens
Copy the Account API Token
Open the Account page, then the API Tokens tab, and copy an Account API Token. Use this token for account-scoped actions such as servers, sender signatures, and domains.
Account → API Tokens
Verify a sender before testing send actions
If you want to run send-email actions, add and verify a sender signature or a sending domain in Postmark first.

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.