Connect Multiple Email Accounts to Gemini
Gemini connects to one Google account at a time and has no Microsoft app at all, but Carly still gets every mailbox you own into one Gemini conversation. Connect each Gmail and each Outlook account to Carly, add Carly to Gemini Spark once as a custom app, and a single chat can search or act in whichever inbox you name.
What one chat can do afterwards
- Search a personal Gmail and a work Outlook in the same question.
- Compare a thread in one company’s mailbox against another’s.
- Produce a morning briefing grouped by inbox.
- Draft or send from the exact address you choose.
- Label, move, flag or archive in the correct account.
- Pull the newest attachment out of whichever mailbox holds it.
Nothing is merged and nothing is forwarded. Each mailbox stays individually addressable, which is what makes “only in the Stryker account” a safe instruction.
Why switching Google accounts does not solve this
The built-in connectors hold one account per provider. ChatGPT, Claude, and Gemini each authorize a single Google identity, and connecting a second one replaces the first rather than adding to it. Switching inboxes means disconnecting and reauthorizing, which is why "personal and work" is still two sessions rather than one.
Google’s own guidance points the same direction: “If you’re connecting to a Google Workspace app, make sure you’re signed in to the same account you use with Google Workspace.” Switching the signed-in account changes which single identity is active. It does not make two active at once, so “did either address get the signed contract” still cannot be answered in one pass.
You work with Carly directly from step 2. The mailboxes are connected and usable the moment you authorize them. Adding Carly to Gemini is what puts them inside a Gemini chat, and that step is optional. Most readers stop here.
The Microsoft side is worse than a limit. Gemini’s Connected Apps list contains no Microsoft app on a personal Google Account or a work one, and there is no IMAP, POP or Exchange option anywhere in the app. An Outlook mailbox is not one account switch away. It is unreachable.
1. Give each mailbox a role
Using fictional addresses:
| Address | Provider | Role in Gemini |
|---|---|---|
fictional.tomas.iverson@gmail.com | Gmail | Personal |
fictional.tomas.iverson@wayfair.com | Google Workspace | Main Company |
fictional.tomas.iverson@stryker.com | Outlook | Client |
Names like Personal, Main Company and Client read better in everyday questions than “Gmail 1” and “Outlook 2.” Keep the full address for anything that changes a mailbox.
2. Connect every mailbox to Carly
- Sign in at carlyassistant.com.
- Open carlyassistant.com/integrations.
- Find Gmail or Outlook and click Connect.
- Choose the first account and approve access.
- Return to the integrations page and click Connect again for the next one.
- Choose Use another account if the provider preselects your previous login.
- Confirm the full address after each authorization before adding another.
Mix providers freely here. A second Gmail sits beside the first, and Outlook sits beside both. A Workspace or Microsoft 365 account may need administrator review first.
3. Add Carly as a custom app in Gemini Spark
- Go to gemini.google.com on a computer.
- Open Settings & help → Connected Apps.
- Under Custom apps for Spark, click Add a custom app.
- Enter
https://carlyassistant.com/mcp/. - If prompted, open Show more under Advanced features to enter credentials.
- Click Next and follow the on-screen instructions.
- Type
@in a Spark task and pick Carly so the request routes through it.
Custom apps are the Spark surface specifically, not general Gemini chat, and Google gates them. Per Google’s custom apps documentation, you need to be 18 or over and in the US, signed in with a personal Google Account because the feature “isn’t available if you sign in with a work or school Google Account,” with Keep Activity on because “Gemini can’t connect to custom apps when this setting is off.” Custom connected apps are English-only for now, and Spark itself needs a Google AI Pro or Ultra subscription. Support has rolled out unevenly across Spark’s surfaces and tiers, so open Connected Apps and look before assuming the option is missing.
Google notes that it “does not control, monitor, or secure third-party MCP servers,” which is worth reading as an instruction rather than boilerplate. Carly’s actions are the mail, calendar and app operations you authorize per account, and you can revoke any one of them from Carly’s integrations page.
The personal-account gate is not a problem here. You sign in to Gemini personally, and Carly holds the Workspace and Microsoft addresses that Gemini’s own sign-in could never reach.
4. Test each address read-only
In
fictional.tomas.iverson@wayfair.com, list the sender and subject of the five newest unread messages. Do not change anything.
In
fictional.tomas.iverson@stryker.com, find the newest thread containing “statement of work.” State the source account and do not draft or send.
Then a question that crosses providers:
Search the Wayfair and Stryker example accounts for “renewal” in the last 30 days. Include the full source address on every row.
5. Route every action by address
Treat
fictional.tomas.iverson@gmail.comas Personal,fictional.tomas.iverson@wayfair.comas Main Company, andfictional.tomas.iverson@stryker.comas Client. Always state the target address before changing data. Wait for approval before sends, moves, deletes, labels or calendar changes.
Then name the target every time:
Draft the reply from
fictional.tomas.iverson@wayfair.com. Do not send yet.
Archive the newsletter thread in
fictional.tomas.iverson@gmail.comonly.
What Gemini’s own Google connection still does well
For the single Google account you signed in with, the Google Workspace app in Connected Apps reads and summarizes Gmail. It stops at that account, it will not send, and it cannot answer a question that spans a personal address and a work one.
It stops at the second account. It stops again at any Outlook mailbox, since no Microsoft app exists to connect. It stops a third time on anything unattended, because the connection answers when you open a chat rather than when mail arrives. Those are the three walls Carly is there to take down.
Gemini’s own connection versus Carly
| Gemini’s Google connection | Carly | |
|---|---|---|
| Gmail accounts at once | One | Every one you connect |
| Outlook accounts at once | None | Every one you connect |
| Gmail and Outlook together | No | Yes, any number of each |
| Reaches Workspace mail from a personal sign-in | No | Yes |
| Says which account it used | Not consistently | On every action |
| Starts when mail arrives | No | Yes |
Carly’s agents also carry their own name, email address and memory, so a colleague or client can write to one directly and the work begins on arrival rather than when you next open a chat. Around the mail sit 260+ native integrations plus your own API key for anything else with an API. Free Zapier-style workflows; AI agents from $35/month.
Connect every inbox at carlyassistant.com.
Quick fixes when a mailbox does not appear
| Problem | Fix |
|---|---|
| Add a custom app is missing | Confirm a personal Google Account, US location, English, AI Pro or Ultra, and Keep Activity on |
| No Microsoft option in Connected Apps | None exists in the Gemini app; connect the mailbox at carlyassistant.com/integrations |
| The provider reused your signed-in account | Choose Use another account rather than the suggested profile |
| A work account stalls at consent | A Google Workspace or Microsoft 365 administrator has to approve before authorization completes |
| The wrong inbox answered | Name the full address; roles are for reading, addresses are for acting |
Frequently asked questions
Can Gemini connect to multiple email accounts?
Not on its own. It authorizes one Google identity and offers no Microsoft app at all. Connecting every mailbox to Carly and adding Carly to Gemini Spark once lets a single chat reach all of them.
Can Gemini read an Outlook inbox?
No Microsoft app exists in Connected Apps, for personal or work Google Accounts, and there is no IMAP or Exchange option. Carly authorizes Outlook mailboxes directly and hands them to Gemini through the custom app.
Does switching Google accounts give me both inboxes?
No. Switching changes which single account is active rather than making two active together.
Do I need Gemini Spark for this?
For the custom app route, yes. Google restricts custom connected apps to Spark on a personal Google Account, in the US, in English.
Does this merge my accounts?
No. Every mailbox keeps its own credentials. Carly routes each read or action to the address you name.
More: How to connect multiple Gmail accounts to Gemini · How to connect multiple Outlook accounts to Gemini · Connect multiple email accounts to ChatGPT · Connect multiple email accounts to Claude · What is Gemini Spark · Best AI assistants for multiple email accounts
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