1
Copy the Mermail MCP URL
Streamable HTTP only — not SSE. Leave auth empty; ChatGPT runs OAuth 2.1 (no API key headers).
MCP endpoint
https://console.mermail.app/mcpCHATGPT
Connect ChatGPT
with OAuth.
Add Mermail as a custom ChatGPT connector. Streamable HTTP plus OAuth — no API key in the connector. Then ChatGPT can list mailboxes, read mail, and finish paid workflows.
Why ChatGPT
Built for the agent you already use.
Mermail gives ChatGPT a dedicated inbox and payment layer so verification, checkout, and receipts stay in the same loop.
Custom connector, URL only
OAuth 2.1 through console.mermail.app
No x-api-key in ChatGPT settings
Streamable HTTP — not SSE
Three steps to connect.
2
Add a custom MCP connector
Open ChatGPT (desktop if installed, otherwise browser) → Settings → Connectors. Create a custom connector named Mermail, paste the URL, transport Streamable HTTP, leave auth empty.
Open ChatGPT Connectors3
Connect, authorize, then verify
Click Connect on the Mermail connector, sign in with Google on console.mermail.app, pick a workspace, then ask ChatGPT to list your mailboxes.
Verify
Ask: "List my Mermail mailboxes" (tool: list_mailboxes)Questions, answered.
Auth, transports, and how to confirm the connection before you trust the agent.
Do I need an API key in ChatGPT?+
No. The custom-connector path is OAuth. Leave auth empty and complete Google consent on console.mermail.app.
The Connectors link opened the browser, not the desktop app.+
On ChatGPT desktop, open Settings (codex://settings) and go to Connectors from there. Then paste the same Streamable HTTP URL.
What about the Official Plugins Directory?+
When Mermail is published there, install from ChatGPT / Codex Plugins for OAuth Apps Connected plus Skills. Until then, use this custom connector.
How do I know Mermail is connected?+
Ask the agent to list your Mermail mailboxes. A healthy connection exposes the hosted MCP tools, including list_mailboxes.
See all integrations
Integration indexClaude
Install the Mermail plugin so Claude can provision an inbox, read verification mail, and finish paid workflows without leaving the terminal.
CodexInstall the Mermail plugin so Codex maps MERMAIL_API_KEY into MCP, loads 11 skills, and can list mailboxes, draft replies, and complete checkout.
CursorInstall the hosted MCP server with OAuth. Cursor discovers Protected Resource Metadata after a 401, then your agent can read mail and act on payments inside the IDE.
OpenClawPoint OpenClaw at hosted MCP with Streamable HTTP and x-api-key. Probe the connection, then let the agent manage inboxes and payment receipts.
HermesAdd Mermail as a Streamable HTTP MCP server in Hermes Agent. OAuth opens a browser, then the agent can list mailboxes, read mail, and finish paid workflows in chat.