How to Connect Multiple Gmail Accounts to Gemini
Gemini reads one Google account at a time, which surprises people because Gemini is Google’s own assistant. Sign in with your personal address and your work Workspace mail is invisible, and the reverse is equally true. Connecting each account to Carly and adding Carly to Gemini Spark gives one conversation a route to every inbox.
Check these requirements first
Custom apps are the mechanism that makes this work, and Google gates them. Per Google’s custom apps for Gemini Spark documentation, you need to:
- sign in to Gemini with a personal Google Account, since the feature “isn’t available if you sign in with a work or school Google Account”;
- be 18 or over and in the US;
- have access to Gemini Spark;
- keep Keep Activity switched on, because “Gemini can’t connect to custom apps when this setting is off.”
Custom connected apps are English-only for now, and available in Gemini Spark in the Gemini web and mobile apps.
That personal-account requirement is not a problem for this setup. You sign in to Gemini personally, and Carly holds the Workspace accounts. The Workspace mail arrives through Carly rather than through Gemini’s own Google connection.
Why Gemini cannot just see both accounts
None of the major assistants let one connector carry two accounts at once. ChatGPT, Claude, and Gemini all authorize a single Google identity per connection, and the documented way to reach the other one is to disconnect and sign in again. A question that spans both inboxes cannot be answered in a single conversation.
Google’s guidance for connecting apps with a work or school account is explicit about staying inside one identity: “If you’re connecting to a Google Workspace app, make sure you’re signed in to the same account you use with Google Workspace.” Everything downstream inherits that. A daily brief built from the signed-in account describes half your day if the other half lives in a second account, and a request to reschedule around your commitments cannot see meetings it has no access to.
Google account switching does not close the gap either. It changes which single account is active rather than letting two be active together, so a question like “did either address get the signed contract” still cannot be answered in one pass.
1. Give each Gmail account a role
Using fictional addresses:
| Address | Role in Gemini |
|---|---|
fictional.helen.okonjo@gmail.com | Personal |
fictional.helen.okonjo@aramark.com | Main Company |
fictional.helen.okonjo@ecolab.com | Client |
Roles like Personal, Main Company, and Client are easier to use in conversation than “the second one.” Keep the full address for anything that changes an inbox.
2. Connect the first Gmail account to Carly
- Sign in at carlyassistant.com.
- Open carlyassistant.com/integrations.
- Find Gmail and click Connect.
- Choose the first Google account.
- Review and approve access.
- Confirm the connected address in Carly.
If a Workspace account requires administrator review, ask the Workspace administrator to approve the connection, then finish authorization.
3. Add the other Gmail accounts
- Return to Carly’s integrations page.
- Select Gmail → Connect again.
- Choose Use another account if Google preselects the first login.
- Sign in to the next Gmail or Workspace identity.
- Complete authorization.
- Verify the full address before adding another.
This is where the Workspace addresses come in, including any that Gemini itself could not reach from a personal sign-in.
4. Add Carly as a custom app in Gemini
- 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.
Google notes that it does not control or secure third-party MCP servers, so it asks you to understand what a server does before connecting it. Carly’s actions are the mail, calendar, and app operations you authorize per account, and you can disconnect any account from Carly’s integrations page.
5. Test each address read-only
Start narrow:
In
fictional.helen.okonjo@aramark.com, list the sender and subject of the five newest unread messages. Do not change anything.
In
fictional.helen.okonjo@ecolab.com, find the newest thread about the renewal. State the source account and do not draft or send.
Then span the accounts:
Search the Aramark and Ecolab example accounts for “statement of work” in the last 30 days. Include the full source address on every row.
6. Reuse this routing prompt
Treat
fictional.helen.okonjo@gmail.comas Personal,fictional.helen.okonjo@aramark.comas Main Company, andfictional.helen.okonjo@ecolab.comas Client. Always state the target address before changing data. Ask before sends, moves, deletes, or labels.
Then name the target in each action:
Draft the reply from
fictional.helen.okonjo@aramark.com. Do not send yet.
Archive the newsletter thread in
fictional.helen.okonjo@gmail.comonly.
Gemini’s Google connection versus Carly
| Need | Gemini’s own Google connection | Carly custom app |
|---|---|---|
| Read the signed-in account’s Gmail | Yes | Yes |
| Reach a second Google account at the same time | No | Yes |
| Mix a personal address with Workspace mail | No | Yes |
| Send from a chosen connected account | The signed-in identity only | Yes, with that account’s permissions |
| Build a brief covering every calendar | Signed-in account only | Yes |
| Keep the routing running on a schedule | No | Yes |
Carly gives Gemini one account-aware toolset spanning every inbox you connect. Carly offers free Zapier-style workflows; AI agents start at $35/month.
Quick fixes
| Problem | Fix |
|---|---|
| Add a custom app is missing | Confirm a personal Google Account, Spark access, and that Keep Activity is on |
| Google reconnected the same address twice | Remove the duplicate and reconnect with Use another account |
| Workspace blocks authorization | Ask the Workspace administrator to approve Carly |
| Gemini answers from the wrong inbox | Use the full address and require source attribution |
| A Workspace address never appears | Reconnect it in Carly and confirm the full address |
Frequently asked questions
Can Gemini use two Google accounts at once?
Not through its own Google connection, which follows the account you signed in with. Connecting each account to Carly and adding Carly as a custom app keeps every inbox reachable from one conversation.
Do I need Gemini Spark?
For the custom app route, yes. Google restricts custom connected apps to Gemini Spark in the web and mobile apps, on a personal Google Account.
Can Carly reach my Workspace mail if Gemini cannot?
Yes. Carly authorizes each Google identity separately, including Workspace addresses, subject to whatever your Workspace administrator approves.
Does this merge my accounts?
No. Every mailbox keeps its own credentials and stays separate. Carly routes each read or action to the address you name.
Related: Can Gemini access Gmail · Gemini alternatives · Multiple Gmail accounts in ChatGPT Work · Manage multiple email accounts with AI · Carly’s Gmail integration
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