Campaign Monitor
Connect Campaign Monitor to manage lists, subscribers and segments, build and send campaigns, track opens and clicks, and send transactional email.
You paste your Campaign Monitor account API key, then pick the client (brand) each PopMCP workspace works with. One client's own API key also works if you add its Client ID.
- Setup time
- 3 min
- Auth
- API credentials
- API base URL
- https://api.createsend.com/api/v3.3
- Rate limits
- Campaign Monitor documents rate limiting only for its transactional endpoints and publishes no fixed number. Responses carry X-RateLimit-Limit, X-RateLimit-Remaining and X-RateLimit-Reset headers, and calls over the limit get 429 `Rate limit exceeded`.
Before you begin
- A Campaign Monitor user with full access. Campaign Monitor only shows the API keys page to full-access users.
- A verified email address on that login. The API key stays hidden until the address is verified.
- At least one client in the account. PopMCP pins every connection to one client and stops with an error on an account that has none.
- Only if you use a client's own API key instead of the account key: that client's Client ID, listed on the same API keys page
Get your credentials
Open Account settings
Sign in to Campaign Monitor. Click your profile picture in the top right corner and choose Account settings.
Open https://YOUR-ACCOUNT.createsend.com/login (replace YOUR-ACCOUNT with your Campaign Monitor account).
Acme Supply
Your profile picture menu, top right of every page.
Account settings is only useful to a full-access user: others cannot open the API keys page.
Open API keys and reveal the key
Select API keys. Click Show API key, or Generate API key if the account has never had one. The same page lists each client's Client ID.
Open https://YOUR-ACCOUNT.createsend.com/login (replace YOUR-ACCOUNT with your Campaign Monitor account).
API keys
Your account API key and the IDs of your clients.
- Acme Supply
- 5a1d********************8c2e
- Northwind Coffee
- c93b********************04fa
Generate a new API key only to rotate: the old key keeps working for 24 hours, then stops.
Copy the account API key
Copy the revealed key in full. Leave the Client IDs alone unless you are connecting with a single client's own API key.
Open https://YOUR-ACCOUNT.createsend.com/login (replace YOUR-ACCOUNT with your Campaign Monitor account).
API keys
Your account API key and the IDs of your clients.
The account key does not expire. PopMCP sends it as the Basic-auth username on every call.
Paste the key into PopMCP and pick the client
In PopMCP, paste the key into Campaign Monitor API key and leave Client ID (only for a client API key) blank. Click Connect Campaign Monitor, choose the client for each PopMCP workspace, and confirm. If you pasted one client's own API key instead, fill in that client's ID in Client ID (only for a client API key) before connecting.
Connect in PopMCP
Open your workspace, choose Campaign Monitor in the marketplace, and fill in the connect dialog:
| Field | What to enter |
|---|---|
| Campaign Monitor API keysecret | In Campaign Monitor, click your profile picture (top right), then Account settings, then API keys, then Show API key (or Generate API key if you haven't made one). You need full access to see it. Stored encrypted, used server-side only.Encrypted with AES-256-GCM on save and never shown again. |
| Client ID (only for a client API key)text | Leave this blank when you paste the account API key: you'll choose the client next. Fill it in only if you paste one client's own API key; the Client ID is listed on the same API keys page. |
PopMCP verifies the credential against Campaign Monitor immediately. On success the connection flips to Verified and its MCP tools are provisioned.
Verify it worked
PopMCP shows the connection as Verified under the client's company name, and asking the AI to list your lists returns that client's real subscriber lists. The connection profile also shows the client's time zone, which Campaign Monitor uses for campaign send dates.
Troubleshooting
401 `{"Code":100,"Message":"Invalid API Key"}`
Why: The key was copied incompletely, or it is an old key more than 24 hours after a new one was generated.
Fix: Click Show API key again, copy the current value in full, and reconnect.
Campaign Monitor didn't accept that API key
Why: You pasted one client's own API key and left the Client ID blank. A client key cannot list clients, so PopMCP had nothing to pick from.
Fix: Either paste the account API key, or keep the client key and fill in that client's ID in Client ID (only for a client API key).
There is no Show API key or Generate API key button
Why: Your user does not have full access, or the email address on your login is not verified yet.
Fix: Verify your email address, or ask an account administrator with full access to copy the key for you.
This Campaign Monitor account has no clients yet
Why: PopMCP connects one client per workspace and the account has none.
Fix: Create a client in Campaign Monitor, then connect again.
Client isn't reachable with this API key any more
Why: The pinned client was deleted, or the key changed so it no longer reaches that client (Campaign Monitor error 102, invalid ClientID).
Fix: Reconnect Campaign Monitor in PopMCP and choose a client from the fresh list.
Integrations broke a day after you generated a new key
Why: After Generate a new API key, the previous key keeps working for 24 hours and then stops.
Fix: Reconnect PopMCP with the new key within that window, along with every other integration that used the old one.
429 `{"Code": 429, "Message": "Rate limit exceeded"}` on transactional tools
Why: Campaign Monitor rate-limits the transactional endpoints. The X-RateLimit-Reset header says how many seconds remain.
Fix: Wait for the reset and retry, and send transactional email in fewer, larger batches (up to 25 recipients per call).
Reference
- Campaign Monitor API documentation
- Campaign Monitor credentials screen:
https://YOUR-ACCOUNT.createsend.com/login(replace YOUR-ACCOUNT with your Campaign Monitor account) - Connect an AI client
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