How to connect ChatGPT to your business email

Quick answer: In ChatGPT on the web, open chatgpt.com/plugins, click the + button and "Add custom MCP server". Enter the name Domailo and the address https://domailo.app/mcp, choose OAuth, accept the risk warning and click "Create as a plugin". ChatGPT opens Domailo's sign-in: you choose the organization and the access and click Allow. Then install the plugin and call it in a chat with @.

Read only
Checked on October 23, 2026

Who it is for

For people who already work in ChatGPT and want it to read and organize company email: contact@, sales@, billing@ or your own mailbox on the company domain.

The connection uses your Domailo login, through the MCP authorization standard (OAuth). There is no key to copy, and ChatGPT acts as you: it sees the same mailboxes you see in the webmail and nothing more.

What it looks like

domailoconnected via MCPExample with fictional data

Request: List the email mailboxes you can access in Domailo.

listar_caixas3 mailboxes · 1 domain

I can access 3 mailboxes on the example.com domain, all able to send:

contact@example.comshared team mailbox
sales@example.comshared sales mailbox
camila@example.comyour personal mailbox

How to connect

In Domailo, make sure you are allowed to use AI assistants. Admins always are; everyone else needs an admin to tick "Can use AI assistants (MCP)" on the invitation or under Edit access, on the Team screen.
In ChatGPT on the web, open chatgpt.com/plugins, click the + button and choose "Add custom MCP server". According to OpenAI, your workspace permissions and security restrictions, such as Lockdown mode, apply here too; if the option does not show up, ask your ChatGPT admin.
Fill in the name Domailo, under "Connection" enter the address https://domailo.app/mcp and choose OAuth as the authentication. Read the risk warning, click "I understand and want to continue" and then "Create as a plugin".
ChatGPT opens Domailo's "Connect assistant" screen. Sign in, choose the organization (if you have more than one) and the access: "Read only" to list and read, or "Read and write" to also send, schedule and organize. Click Allow.
Install the plugin in your personal plugins (or in the workspace where you created it). In a chat, type @ and pick Domailo, and ask for something simple, such as "List my mailboxes in Domailo".
To disconnect, revoke the connection in Domailo under Settings › AI integrations, where it shows the "Connected via OAuth" badge, or remove the plugin in ChatGPT.

Ready-to-copy prompts

Swap the addresses and names for yours. The more specific the request (mailbox, time period, what the reply must say), the better the result.

Using Domailo, list my mailboxes and tell me which ones can send email.
Show the 10 most recent conversations in the Inbox of contact@example.com.
Read the latest conversation with Camila Rocha and summarize it in three lines.
Which conversations are in the Pending folder, across all my mailboxes?

Depending on your setup

Personal account or workspace: You add the plugin to your personal plugins or to the workspace where you created it; people who use the workspace plugin connect with their own Domailo login and see only their own mailboxes.
More than one organization in Domailo: The consent screen asks for the organization. To use two, connect Domailo again and choose the other: each connection is valid for one organization.

Permissions needed

"Read only" access is enough. Tools used: listar_caixas.
Admins, and people an admin allowed to use AI assistants. Each person sees only the mailboxes they already open in the webmail.
Included in the Startup, Essential and Team plans and during the trial.

Caveats and limits

According to OpenAI, write actions ask for confirmation by default, and ChatGPT treats every tool without the read-only mark as a write. Review what will be sent before approving, and only remember the decision, within a conversation, for tools you trust.
Through MCP, Domailo sends plain text to one recipient per message: no attachments and no CC/BCC. Attachments and formatting are added to a draft in the webmail.
Access renews on its own every hour. A connection unused for 90 days expires and has to be made again.
MCP is included in the Startup, Essential and Team plans and during the trial. The legacy Free plan does not include MCP.
Checked on 2026-10-23 with a real account: the OAuth connection worked and ChatGPT listed the mailboxes. The other commands use the same tools as Claude, but were not tested one by one in ChatGPT.

Frequently asked questions

Can ChatGPT send email through Domailo?

Yes, if you grant "Read and write" on the consent screen. The enviar_email tool sends now or schedules, and salvar_rascunho saves a reply for you to review first. With "Read only", ChatGPT can only list and read conversations, and write actions ask for confirmation in ChatGPT.

Do I need an API key to connect ChatGPT?

No. The connection uses your Domailo login (OAuth 2.1 with PKCE): you sign in, choose the access and allow it. The personal key, created in Settings › AI integrations, is for clients that ask for an authorization header, such as Claude Code and Cursor. Never paste the key into a chat: if that happens, revoke it right after.

Does ChatGPT see every mailbox in the company?

It sees exactly what you see in the webmail. Admins open every mailbox in the organization; people with the agent role open only the mailboxes linked to them. Permission is checked again on every request, so removing a mailbox from someone takes effect immediately.

How do I disconnect ChatGPT?

In Domailo, open Settings › AI integrations and revoke the connection marked "Connected via OAuth". Access ends immediately. Resetting your password with the default option also ends every assistant connection.

Which ChatGPT plan do I need to add the server?

OpenAI decides which plans and workspaces can add custom MCP servers, and that rule changed during 2026. If the "Add custom MCP server" option does not appear at chatgpt.com/plugins, check OpenAI's help center or ask your workspace admin.