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.
1. Add your Gmail and Outlook mailboxes to Carly
- Sign in at carlyassistant.com.
- Open carlyassistant.com/integrations.
- Find Gmail and Outlook, click Connect, and authorize the mailbox.
- Click Connect again for the next one, and keep going for as many mailboxes as you want.
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.
Carly connects to thousands of apps, so while you are on that page you can add your calendars, files, CRM, and anything else you want Gemini to reach through the same connector.
2. 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.
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 your client account” a safe instruction.
Why switching Google accounts does not solve this
The built-in connectors hold one account per provider. 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. Carly holds all of them at once.
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 thousands of other apps. 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 address in the prompt |
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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