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Connect your mailbox to Grok
Add your own mailbox to Grok as a custom MCP connector: paste its URL, sign in, pick the mailbox. Outlook, Gmail, iCloud, Yahoo or IMAP, tested live.
Add Mailbox MCP to Grok as a custom connector
To connect Grok to your email, you add Mailbox MCP as a custom connector: you give Grok one URL, sign in to us once, and Grok can read, search, draft and send in that mailbox. These are the screens Grok showed on , when we connected our demo mailbox.
You need the mailbox connected in the control panel first, because that's where the mail server sign-in is checked and kept. Grok never sees it.
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Open Plugins, then New Connector
In Grok on the web, open Plugins in the sidebar (its address is grok.com/connectors). On the Connectors tab, select the black New Connector button.
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Choose Custom
The list that opens starts with Custom, "Add your own custom connector", above Grok's own catalog. Select it.
New Connector in Grok, 9 October 2026. Custom sits above the catalog. -
Name it and paste the connector URL
Grok asks for "a custom name and an MCP server URL". Name it after the mailbox, because that name is how Grok lists it and how it labels every step it takes. Paste the mailbox's own URL into Server URL and select Add Connector.
Server URL One per mailbox, from its Connector tabhttps://mcp.mailbox-mcp.com/db/mcp/YOUR-MAILBOX-KEY
The Custom Connector form, filled in for our demo mailbox. The end of the URL is blurred here. There's no client ID and no secret to find. Grok registers itself with our server, which is why the next screen already knows its name.
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Choose the mailbox and what Grok may do
Grok opens our sign-in in a pop-up. It says Grok is asking to open one of your mailboxes and shows the address Grok will be sent back to, which we check. The mailbox from your URL is already chosen. Pick what Grok may do, then select Connect this mailbox.
Our consent screen as Grok opened it. We chose Read only for the demo. Read only reads, searches and checks, and changes nothing. Draft and file adds drafts, filing and flags. Send and delete is everything the mailbox can do. Start low if you're unsure: you can raise it later without touching Grok.
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Check it's connected
The pop-up closes itself and the connector appears under Connected, with mcp.mailbox-mcp.com under its name.
Connected. Grok drew Box's logo beside our connector; the address under the name is the one to trust.
The Box logo is Grok's, not ours
When we added our connector, Grok put Box's logo beside it, in the list and in the chat menu. It's almost certainly matching the "box" in "mailbox". The connector is still ours: mcp.mailbox-mcp.com is under its name, and our sign-in was the one that opened.
Use the Grok email connector in a chat
In a chat, select + in the message box, then Connectors. Each connector has its own switch, and ours was already on in a new chat. The message box also suggests typing @ to pick one of your apps.
Then ask for something only your mailbox can answer, and name the mailbox if you have more than one. We asked about an invoice in our demo mailbox, at Read only:
Grok searched the mailbox for "Kestrel Supplies", opened the email, read the PDF attached to it, and answered with the total and the due date. The email was still unread afterwards, because reading through Mailbox MCP never marks a message read. Our server's log shows the same 3 calls.
One thing to know: Grok also ran a web search with the words of the question before it used the mailbox. The "1 source" under its answer is that web result, not your email. Your mail goes to Grok only when it calls the connector.
Try this first
Using my mailbox connector, list my 5 most recent emails with sender and subject, and tell me which need a reply from me. Don't change anything.
Asking changes nothing: listing and reading never set the read flag, so your unread markers stay exactly as they were.
What Grok did with a real mailbox
The demo shows the steps. The test that matters came earlier the same day, on one of our own business mailboxes, connected to Grok at Send and delete. The only rule we gave was: don't delete or move anything.
- It caught up on the last 24 hours, found the replies we owed, and listed the emails still waiting on an answer.
- It checked the domain's SPF, DKIM and DMARC records, and opened a PDF invoice to read the amount.
- It saved a reply as a draft, threaded under the message it answered, and left it unsent.
- It sent a test email with a file attached. The email arrived with the file, and one copy was filed in Sent.
We checked each of those in the mailboxes themselves, not in Grok's summary. Every call Grok made that day succeeded, and nothing was deleted or moved.
Try it on your own mailbox: 5 MCP calls a day are free, with no card. That is enough to connect Grok and see it answer.
Grok and Outlook or Microsoft 365
Grok's catalog lists its own Outlook connector, described as "Search and draft emails" when we looked on 9 October 2026. Through Mailbox MCP the same mailbox can also send, reply inside the thread, file and read attachments, once you allow it.
A work mailbox connects with one Microsoft sign-in: connect Outlook for work (Microsoft 365). A personal Outlook.com, Hotmail or Live address connects over IMAP after one switch in Outlook.com's settings: connect Outlook.com and Hotmail shows where it is.
Grok and Gmail
Grok's catalog describes its Gmail connector the same way, "Search and draft emails". To connect Grok to Gmail through Mailbox MCP, a Gmail or Google Workspace mailbox connects with an app password, which needs 2-Step Verification by phone or authenticator app: connect Gmail walks through it.
If Google says the app password setting isn't available for your account, Gmail app password not available explains the usual cause.
iCloud Mail and Yahoo Mail in Grok
Neither had a connector in Grok's catalog when we looked on 9 October 2026, and both work through Mailbox MCP. iCloud Mail needs an app-specific password from your Apple Account, and the same password opens your iCloud calendar: connect iCloud Mail and your Apple calendar.
Yahoo Mail connects as an IMAP mailbox with a Yahoo app password, made under External connections on Yahoo's Account Security page. Paste it in the control panel and the lookup fills in Yahoo's servers: app passwords for Yahoo, iCloud and Fastmail.
Grok and IMAP email on your own domain
Email on your own domain, from a web host, Fastmail, Zoho or GMX, reaches Grok through Mailbox MCP over IMAP, with the same tools as any other mailbox. You add it in the control panel once, with the address and password your mail app already uses, and the panel looks up the server settings.
Connect any IMAP mailbox has the details, including what to do when the lookup can't find your host.
Which Grok plans can add a custom connector
SpaceXAI, the company behind Grok, puts it simply:
Connectors are available to all Grok users and let Grok access your external tools and data sources directly within a conversation.
SpaceXAI, Grok connectors
That matches what we saw. The Grok account we tested with showed Free under Subscription. It is linked to an X account on X Premium, so we can't rule that out as a factor, but nothing in the steps above asked for a paid plan.
Business and Enterprise work differently, and SpaceXAI says so plainly:
On Grok Business and Enterprise plans, a team admin must add a connector in the cloud console before team members can connect and use it.
SpaceXAI, Connector management
So on a company plan, the first step is your admin's: in console.x.ai, Grok Business, then Connectors, then + Add Connector and Other, with the mailbox's URL. Members then connect their own accounts on grok.com/connectors. We haven't tested a Business account yet.
No tunnel needed: a hosted MCP server for Grok
Most of what's written about Grok and MCP servers is about tunnels, and SpaceXAI's own guide explains why:
When you add a custom MCP connector, Grok's servers need to reach your MCP server over the public internet.
SpaceXAI, Custom MCP server tunneling
An MCP server running on your own laptop can't be reached that way, so people put a tunnel in front of it and keep both running. Mailbox MCP is a remote MCP server already: it runs on our servers, Grok reaches it over HTTPS, and there's nothing on your machine to install or keep open.
So as a Grok MCP connector there's nothing to keep running. And the URL is fixed: SpaceXAI notes that most free tunnel URLs change each time the tunnel restarts, which means removing the connector and adding it again. Ours doesn't change.
Remote and local MCP servers covers the difference properly.
Change what Grok may do, or disconnect it
Every connection shows on the mailbox's Connector tab in our control panel, under the name of the app that made it. Grok's shows as Grok, with its permission level and when it last signed in.
Change raises or lowers what Grok may do, with no need to touch Grok. Disconnect ends the connection at once, and Grok can reach nothing until you connect it again. A connection can only ever reach the one mailbox it was approved for.
In Grok, selecting the connector under Connected shows the tools it was given, which follow the level you chose, with Reauthenticate and Disconnect. Reauthenticate is Grok's button for signing the connector in again.
Disconnect in both places
Disconnecting in Grok removes the connector from Grok straight away, with no confirmation. It doesn't end the connection on our side: when we tried it, the mailbox's Connector tab still listed Grok until we pressed Disconnect there too. To close the door for good, do both.
For a second mailbox, add a second custom connector with that mailbox's own URL, named after it. Each one opens one mailbox, the same rule as in every other app.
Questions about connecting Grok to email
How do I connect Grok to my email?
Add Mailbox MCP as a custom connector. In Grok, open Plugins, then New Connector, then Custom. Name it after your mailbox, paste the connector URL from that mailbox's Connector tab in our control panel, and select Add Connector. Grok opens our sign-in in a pop-up: choose the mailbox and what Grok may do with it, and you're done.
Does Grok work with Outlook.com, iCloud, Yahoo or IMAP email?
Yes, through Mailbox MCP. Outlook and Microsoft 365, Outlook.com and Hotmail, Gmail, iCloud Mail, Yahoo Mail, Fastmail, Zoho, GMX and any IMAP mailbox on your own domain all connect the same way: once in our control panel, then once in Grok as a custom connector.
Can Grok send emails?
Yes, through Mailbox MCP, when you give the connection permission to send. On 9 October 2026 Grok sent a test email with a file attached from one of our own mailboxes: it arrived with the file, and one copy was filed in Sent. It also saved a reply as a draft, threaded under the message it answered.
Do I need Grok Business or SuperGrok to add a custom connector?
No. SpaceXAI says connectors are available to all Grok users, and our test account showed Free under Subscription (it is linked to an X Premium account). On Grok Business and Enterprise a team admin adds the connector in the cloud console first, and members then connect their own accounts.
Why is my Grok connector not working?
Check 3 things. The connector is switched on in that chat: select +, then Connectors. The URL is the mailbox's own, from its Connector tab, not the bare server address. And the permission you chose allows what you asked for: a Read only connection can't draft or send. Naming the connector in your request helps Grok pick it.
Why does Grok show the Box logo next to Mailbox MCP?
Grok drew Box's logo beside our connector when we added it on 9 October 2026, probably matching the "box" in "mailbox". It is still our connector: the line under its name says mcp.mailbox-mcp.com, and our sign-in is the one that opened.
Does Mailbox MCP keep a copy of my email?
No. Mailbox MCP reads your mail from the mailbox when Grok asks and keeps no copy of your messages. Grok never sees your mailbox password: it signs in to us, and we keep your mail server credential encrypted at rest with AES-256. Reading a message doesn't mark it read.
Where to go next
Once Grok can reach the mailbox, what AI can do with your email has ideas for what to ask, and Mailbox MCP security says what we hold and what we never keep.
The same mailbox works in other assistants too, with the same URL: Claude.ai and ChatGPT each have their own page. Mailbox MCP pricing has the free allowance and Pro.
- The screens on Grok Business and Enterprise, where SpaceXAI says a team admin adds the connector in the cloud console first and members then connect their own accounts. We tested a personal account.
- Whether the connect step completes in the Grok phone app. Every connection we made was in a web browser.
Read 9 October 2026 Every value on this page came off SpaceXAI: Grok connectors on that day. The steps and the screenshots are our own, from a Grok account on the Free plan, the same day. If it has changed since, tell us and we will read it again.