---
title: "Connect multiple Gmail accounts to Claude with Mailera MCP"
description: "Connect two Gmail inboxes to Claude through Mailera MCP. Scope a read-only key, check mailbox identity, and keep personal and work results separate."
url: https://mailera.app/en/blog/claude-multiple-gmail-accounts
published: 2026-10-25
updated: 2026-10-25
---

# Connect multiple Gmail accounts to Claude with Mailera MCP

Use one read-only workflow for two authorized Gmail inboxes, and check the source mailbox before trusting any combined search.

## Can you connect multiple Gmail accounts to Claude?

Yes, through Mailera’s MCP connection: connect each Gmail mailbox, scope a Read key to their group, and use **Copy MCP config** in a compatible Claude client. Keep the mailbox identities separate even when you search them together.

MCP is the protocol an AI client uses to discover and call tools. Here, those tools connect Claude to Mailera, which connects to your existing inboxes. The [Mailera MCP overview](https://mailera.app/en/mcp) explains that connection; the broader guide to [email MCP servers for existing mailboxes](https://mailera.app/en/blog/email-mcp-server-existing-mailboxes) covers the architecture.

| Item | Purpose | Where it belongs |
| --- | --- | --- |
| Each Gmail app password | Connects that Google mailbox to Mailera | That mailbox’s connection details |
| Mailera API key | Authorizes Claude’s MCP requests | The client’s MCP authentication configuration |
| Mailbox ID and address | Identify the source of a message | Search results and verification records |

Do not give Claude your Gmail app passwords. It uses the Mailera key instead.

![Two Gmail inboxes connect to one Mailera group, which Claude accesses through MCP with a scoped Read-only key.](https://mailera.app/media/1fb68d552e0a1a93/connect-multiple-gmail-accounts-to-claude-with-mailera-mcp-en-1200.jpg)
_App passwords connect the mailboxes to Mailera. A separate API key controls Claude’s access._

## What do you need before connecting both inboxes?

Use two existing Gmail or Google Workspace mailboxes you own or are authorized to access. You also need an Admin or Leader role to add them in Mailera.

The [Mailera Gmail connection](https://mailera.app/en/providers/gmail) uses app passwords, not Google OAuth. Google recommends “Sign in with Google” when an app offers it; this connection follows Google’s app-password requirements instead.

Google’s [app-password guidance](https://support.google.com/accounts/answer/185833) requires 2-Step Verification. The option may be unavailable for accounts using only security keys for 2-Step Verification, accounts with Advanced Protection, or work and school accounts. For personal Gmail accounts, IMAP access is always on, so there is no separate toggle to check there.

For Workspace, check the organization’s policy first. Google’s [administrator guidance for POP and IMAP](https://knowledge.workspace.google.com/admin/sync/turn-pop-and-imap-on-or-off-for-users?visit_id=639285500007078289-1999594546&rd=1) explains that administrators can disable IMAP or restrict it to specified OAuth clients. Mailera cannot override those restrictions.

Choose a mailbox group containing only the inboxes intended for this workflow. Do not include unrelated client mailboxes just because they are in the same workspace. Combining personal and work email also needs to fit your organization’s rules.

## How do you connect both Gmail accounts to Mailera?

1. Open **Mailboxes → Add mailbox → One mailbox**. Enter the first address in **Email address**, check the detected provider, and select **Continue**. For a Workspace domain, confirm that Gmail is selected rather than assuming detection is correct.
2. Follow Google’s app-password instructions for that account. Enter the app password in **Password**, not your ordinary Google sign-in password. Choose the intended **Mailbox group**, then select **Test & connect**. The test does not send an email.
3. Wait for `Connected <email>`, then repeat with the second account and its own app password. Select the same intended group.
4. After creating the Read key in the next section, use the mailbox-list REST request shown later to inspect each mailbox’s `email`, `status`, and `last_sync_at`. A successful first connection does not tell you whether the second mailbox is ready.

The Gmail MCP app-password walkthrough covers credential setup in more detail. Keep passwords out of prompts, screenshots, and copied notes.

Mailera initially loads messages within the retention period, newest first. The free plan retains messages for 30 days, so a connected inbox does not mean Claude can search your complete Gmail history.

![Mailboxes page with two distinct Gmail mailbox rows and their connection status and last sync.](https://mailera.app/media/20b12d21489723ce/connect-multiple-gmail-accounts-to-claude-with-mailera-mcp-en-1200.jpg)
_Check each mailbox separately before giving Claude access to their group._

## How do you give Claude access to both inboxes?

5. Open **Settings → API key tab → Create key**. Give the key a **Descriptive name**, such as “Claude Gmail reading,” and set **Mailbox scope** to the group containing the two inboxes. Avoid the all-groups option.
6. Select only **Read** and choose an **Expiration**. Leave **Send messages**, **Move messages**, and the other permissions disabled. Copy the key when **Key created — copy it now** appears; it is shown only once.
7. Use **Copy MCP config** for Claude. Keep the credentials in the client’s supported MCP configuration, never in a chat message. Use the [Mailera Claude integration guidance](https://mailera.app/en/integrations/claude) for the client-side setup rather than transferring menu instructions between Claude web, Desktop, Code, and Cowork.
8. Once the client loads the tools, ask Claude to call `list_mailboxes`. Check that both expected addresses appear and that mailboxes outside the selected group do not.

The MCP endpoint is `https://mailera.app/api/public/v1/mcp`. Mailera authenticates requests with an `Authorization: Bearer` header; the copied configuration belongs in a client setup that supports that authentication path.

![Mailera API-key settings with one mailbox group selected and only Read permission enabled.](https://mailera.app/media/047ef7ca00571d35/email-human-in-the-loop-an-approval-workflow-for-ai-agents-en-1200.jpg)
_Limit the key to the intended group and Read permission; keep the key itself hidden._

The initial task needs `list_mailboxes`, `search_messages`, and `get_message`, all of which require the read scope. A Read-only key cannot authorize `send_email` or `move_message`. For other tasks, see the [Mailera MCP tools guide](https://mailera.app/en/blog/mailera-mcp-tools).

## How do you verify that Claude keeps the inboxes separate?

Place a harmless message in each authorized inbox, with different subjects. For example, use “Mailbox test — personal” in one and “Mailbox test — work” in the other. Record the actual destination address beside each subject before asking Claude to search.

Start with this prompt:

> Search both connected Gmail inboxes for the mailbox test messages. Group results by mailbox address and include the subject. Use the source mailbox from the tool results, not an address inferred from the message text. Do not move or send anything. If the source mailbox is unclear, stop and tell me.

`list_mailboxes` establishes which accounts are available. `search_messages` locates messages; `get_message` retrieves a message’s content. Have the client use each tool’s declared parameters rather than inventing arguments from a REST example.

The [MCP tools specification](https://modelcontextprotocol.io/specification/2025-06-18/server/tools) defines discovery through `tools/list` and parameters through each tool’s `inputSchema`. A REST parameter name is not automatically an MCP argument name.

Run the account-specific checks before the combined search. Fill in the observed-result column yourself:

| Test | Expected mailbox | Observed result to record | Pass condition |
| --- | --- | --- | --- |
| Search the personal mailbox | Personal address | Returned address and subject | Personal test message belongs to that mailbox |
| Search the work mailbox | Work address | Returned address and subject | Work test message belongs to that mailbox |
| Search both together | Both addresses | Each subject beside its source address | Both messages retain the correct source |
| Read each test message | Its original mailbox | Source identity and message content | Read result agrees with search result |

Do not accept headings such as “Personal” and “Work” as proof. Claude could infer them from subjects. Require the source account from the tool output, or resolve the returned mailbox ID to its address.

For a direct identity check outside Claude, this REST request lists mailboxes visible to the same key:

```bash
curl --fail-with-body \
  -H "Authorization: Bearer $MAILERA_API_KEY" \
  'https://mailera.app/api/public/v1/mailboxes?limit=100'
```

Set `$MAILERA_API_KEY` privately in your shell first. In the response, match `data[].id` to `data[].email` and check `group_id`, `status`, and `last_sync_at` for each mailbox. REST message results also include `mailbox_id` and `mailbox_email`; use those fields when inspecting REST results, not as assumed MCP field names.

If the MCP output gives you neither a source address nor an ID you can resolve, stop. Do not use that combined search for account-specific decisions until attribution is clear.

## What commonly goes wrong?

**Only one mailbox appears.** Check that the second mailbox connected successfully and belongs to the key’s selected group. Do not widen access to all groups as a shortcut.

**The app password is unavailable or rejected.** Check Google’s eligibility rules and your administrator’s policy. Google also revokes app passwords when the Google Account password changes, so a previously working connection may need a new app password.

**Claude cannot load the tools.** Check the client’s MCP configuration and authentication support. Then check key expiration, revocation, and any IP restrictions. Inspect settings without printing credentials into chat or logs.

**Recent messages are missing.** Check connection status and last sync. Mailera checks active mailboxes more often than idle ones; inactive mailboxes can go to sleep and wake up again when they're used. Synchronization is not guaranteed to be instantaneous. The `sync_mailbox` tool requires the separate **Sync** permission, so the Read-only key cannot invoke it.

**Older messages are missing.** Check retention before treating this as a failed connection. Initial loading is limited to the retention window.

**A message is attributed to the wrong inbox.** Resolve the source mailbox ID to its address, then repeat the single-mailbox search. Do not ask Claude merely to relabel the same unverified summary.

## How do you keep personal and work email safe?

Treat incoming email as untrusted data, not instructions. A message asking Claude to reveal secrets, change configuration, or send information elsewhere is content to analyze, not authority to act. Apply that rule even when the message appears to come from someone you know.

Use the smallest mailbox group and only the permissions needed. Read-only access still exposes sensitive email. Prompt wording cannot replace the key’s enforced scope, and putting two inboxes together does not make sharing their contents appropriate. The broader [guide to email for AI agents](https://mailera.app/en/blog/email-for-ai-agents) covers using existing mailboxes; review [Mailera’s security information](https://mailera.app/en/security) before granting access to work mail.

Keep this workflow read-only. If you later enable sending, require confirmation of the sending mailbox, recipients, and message content before every send.

To stop the workflow’s access, revoke its Mailera key and remove the client configuration. Mailera rejects calls immediately after revocation. Revoking a Google app password separately removes access through that password.

Mailera connects existing mailboxes; it does not create Gmail accounts or email addresses.

**Let AI agents use your mailbox via MCP** — Add Mailera's MCP server to Claude, Cursor or VS Code so agents can read, categorize and reply to email messages. [Learn how to use MCP](https://mailera.app/en/docs#mcp)