How do I set up Gmail MCP for multiple accounts or users?

If you are one person with several inboxes, connect them through one Gmail MCP server that gives each account a name, or run one server per account. Not sure whether your assistant's built-in connector is enough? See the connector vs MCP server comparison, or the list of Gmail MCP servers compared. If several people each need their own login, that is a separate multi-user setup. Nickbox, a hosted read-only server, covers one person with up to 5 inboxes.

What is the difference between multiple accounts and multiple users?

Multiple accounts means one person with several inboxes, such as work, personal and billing. Multiple users means several people, each with their own inbox and their own permission. The first needs labels. The second needs tenancy: separate tokens, separate access rules and a way to keep each person's data apart.

Most searches for "Gmail MCP multiple users" come from someone in the first group. A freelancer with a personal address and two client inboxes has three accounts and one user. A five-person agency has five users, and that calls for a team product, which Nickbox is not.

Which options exist for multiple Gmail accounts?

There are five common routes: one server per account, an open-source multi-account server you run locally, Composio, a hosted read-only server like Nickbox, and ChatGPT's native support. They differ most in who runs the infrastructure and whether the assistant can send mail.

Option	Where it runs	Setup	Can send mail	Works in
One server per account	Your machine	Repeat the install for every inbox	Depends on the server	Any MCP client
Open-source multi-account (for example gmail-mcp-multi)	Your machine	Your own Google Cloud project, OAuth client and hosting	Depends on config	Any MCP client
Composio	Hosted	Composio account, then one custom connector with a label per connection	Yes, its Gmail toolkit includes sending	Clients that accept a custom connector
Nickbox	Hosted	Sign in with Google, connect each inbox, paste one URL	No, read-only	Claude, Gemini CLI, ChatGPT developer mode, Cursor, VS Code, Gemini via Spark
ChatGPT native	OpenAI	Built in since 2026-08-28, per press coverage	Yes	ChatGPT only

The one-server-per-account route is the common workaround, and it works. It also means every new inbox adds another entry to configure and another name the assistant has to pick between. The open-source servers solve that with an alias or an account argument on each call, at the price of creating your own OAuth client in Google Cloud and running the process yourself.

How do I set up Nickbox for several inboxes?

Setup takes four steps and no Google Cloud project. Nickbox is in a limited beta. It has not finished Google's verification yet, so Google lets it connect only 100 Gmail accounts and places are limited.

1. Sign in to Nickbox with Google and connect your first inbox. Google asks for the read-only Gmail permission (gmail.readonly).
2. Connect up to four more inboxes and give each a nickname: work, personal, billing.
3. Copy your MCP URL from the dashboard.
4. Paste the URL into your client as a custom MCP connector and approve the OAuth sign-in. The client guides are at Claude, ChatGPT, Gemini, Cursor, VS Code and Claude Code.

After that you can ask "search work and billing for invoices from March" and the assistant calls the right inboxes. The server exposes five tools: list_accounts, search_emails, search_all_accounts, read_email and list_labels.

Which option should I choose?

Choose by what you already pay for and what you need the assistant to do with mail. If you only need to read and search, a read-only hosted server is the smallest setup. If you need to send, or you live in ChatGPT, another row of the table fits better.

Your situation	Best fit
You only use ChatGPT and want it to send mail	ChatGPT native
You want free, full control and can run a process	Open-source multi-account server
You need many integrations, or sending, in one connector	Composio
You use Claude, Cursor, VS Code or Gemini CLI and want read-only search across 2 to 5 inboxes	Nickbox
You have one inbox	Your client's built-in Gmail connector

What does Nickbox store, and what does it not do?

Nickbox stores connection metadata and one encrypted refresh token per inbox in Google Cloud Secret Manager. It does not write message contents to its database or logs. It cannot send, draft or delete mail, because the permission it holds is read-only. It does not offer shared inboxes, Outlook or IMAP in this release. The details are on the security page, and the price is on the pricing page: US$5 a month or US$48 a year, with a 7-day trial that needs a card.