Every AI app connects to Mailercloud the same way: add a custom connector with the Mailercloud address, then sign in with a Mailercloud API key. This guide shows where to do that in each app.
Create an API key. In Mailercloud, go to Settings > API Keys and create a key. Name it after the app (for example "Claude") and copy it. You only see it once.
Add the connector. In your AI app, add a custom connector (also called an MCP server or app) named Mailercloud, with this address:
https://mcp.mailercloud.com/mcp
Sign in. Click Connect. A Mailercloud sign-in page opens: paste your API key and click Connect. Then test it by asking: "Is my Mailercloud account connected?"
AI apps change their menus often. If a step below doesn't match what you see, follow the app's own guide (linked in each section) and use the address above.
App | Best for | Where to add it |
Claude (web, desktop, mobile) | Everyday marketers | Customize > Connectors > Add custom connector |
ChatGPT | Everyday marketers | Apps / connectors settings > add a custom MCP server |
Perplexity | Research plus action | Plugins (sidebar) > Add custom |
Cursor | Technical users | mcp.json |
Claude Code, Gemini CLI | Technical users | One command in the terminal |
Microsoft Copilot Studio | Teams building their own agents | Agent > Tools > Add a tool > Model Context Protocol |
Any other app that supports remote MCP servers works too, using the three steps above.
Custom connectors are available on Claude Free (one custom connector), Pro, Max, Team and Enterprise. On Team and Enterprise, an owner adds the connector for the organisation first.
Open claude.ai (or the desktop app) and go to Customize > Connectors. In older versions this is Settings > Connectors.
Click + Add > Add custom connector. Enter the name Mailercloud and the address https://mcp.mailercloud.com/mcp, then click Add.
Click Connect next to Mailercloud, paste your API key on the Mailercloud sign-in page, and click Connect.
In a chat, click + > Connectors and make sure Mailercloud is switched on.
Team and Enterprise owners: go to Organization settings > Connectors > Add > Custom > Web, enter the name and address, and save. Members then find Mailercloud under Customize > Connectors and click Connect.
Claude asks before using a tool. Approve each action, or choose "Allow always" only for tools you're comfortable with. Tip: switch off connectors you aren't using in a chat, so Claude picks the right tools. Anthropic's guide: Get started with custom connectors.
Custom MCP connectors are available on some paid ChatGPT plans, on the web. On business plans, an admin or owner may need to add them, and some plans allow reading only. Check OpenAI's help for your plan.
In ChatGPT on the web, open the apps or connectors settings and choose to add a custom MCP server. On some plans you first switch on Developer mode in the advanced settings.
Enter the name Mailercloud, a short description (for example "My Mailercloud email marketing account") and the address https://mcp.mailercloud.com/mcp. Choose OAuth sign-in if asked, accept the notice, and create it.
Paste your API key on the Mailercloud sign-in page and click Connect.
In a new chat, click + and pick Mailercloud (or type @Mailercloud) to use it.
OpenAI's guide: Connect from ChatGPT.
Open Plugins in the sidebar and select Add custom.
Enter the name Mailercloud and the address https://mcp.mailercloud.com/mcp, choose OAuth sign-in, and save.
Paste your API key on the Mailercloud sign-in page and click Connect.
Remote connectors may need a paid Perplexity plan. Perplexity's guide: Local and remote MCPs for Perplexity.
Add Mailercloud to ~/.cursor/mcp.json (all projects) or .cursor/mcp.json (one project):
{"mcpServers": {"mailercloud": {"url": "https://mcp.mailercloud.com/mcp"}}}
Cursor then shows a sign-in link for Mailercloud: paste your API key there. To skip the sign-in page, add your key as a header instead:
{"mcpServers": {"mailercloud": {"url": "https://mcp.mailercloud.com/mcp", "headers": {"Authorization": "YOUR_API_KEY"}}}}
Use Mailercloud from Cursor's chat in Agent mode. If Cursor warns about too many tools, switch off the Mailercloud tools you don't need in its MCP settings. Cursor's guide: Model Context Protocol.
Run this in your terminal, with your own API key:
claude mcp add --transport http mailercloud https://mcp.mailercloud.com/mcp --header "Authorization: YOUR_API_KEY"
Then type /mcp in Claude Code to check that Mailercloud is connected.
gemini mcp add --transport http mailercloud https://mcp.mailercloud.com/mcp
Then run /mcp auth mailercloud and paste your API key on the sign-in page (this needs a browser on the same computer). Check it with gemini mcp list. Google's guide: MCP servers with Gemini CLI.
Open your agent and go to Tools > Add a tool > New tool > Model Context Protocol.
Enter the name Mailercloud, a description, and the address https://mcp.mailercloud.com/mcp.
Choose API key authentication and use your Mailercloud API key, or OAuth 2.0 with dynamic discovery. Then create the connection and add it to the agent.
Your organisation's data policies apply to the connector. Microsoft's guide: Add an existing MCP server to an agent.
What you see | What to do |
The sign-in page doesn't open | Allow pop-ups for your AI app's website and click Connect again. |
"Invalid API key" or the connection fails | Check the key under Settings > API Keys. If it was deleted or you're unsure, create a new one and connect again. Check the address is exactly https://mcp.mailercloud.com/mcp. |
The assistant doesn't use Mailercloud | Make sure the connector is switched on in this chat (+ > Connectors in Claude; pick it with + or @ in ChatGPT). Start a new chat, or name it: "Using Mailercloud, ...". |
It worked before and suddenly stops | The API key may have been deleted. Remove the connector, create a new key, and add it again. |
Wrong Mailercloud account | The connector uses the account the API key belongs to. Remove it and connect again with a key from the right account. |
Cursor: "too many tools" | Switch off the Mailercloud tools you don't need in Cursor's MCP settings. |
Remove the connector in your AI app, then delete the API key under Settings > API Keys in Mailercloud. Deleting the key stops all access through it immediately.
Next: read Mailercloud + AI assistants: the complete guide and try the prompts in Everyday ways to use Mailercloud with AI. Need help? [email protected]
