Deal with more than one organization for long enough and you end up with more than one mailbox, rarely on the same platform. A Gmail account from a client, a Microsoft 365 address from a contract, an old address on a host nobody remembers choosing, and your own domain. Four providers, one inbox is the arrangement that stops you checking four places.
The mechanism is external accounts: mailboxes elsewhere connected over IMAP so their mail appears alongside your own. This page covers what that actually gives you, what it can't fix, and the plan limits that decide how many you can connect.
How Four Providers, One Inbox Works
You give us the connection details for a mailbox hosted somewhere else, and we connect to it the way any mail client would. Its folders and messages appear in the same interface as your hosted mail.
The important part is what happens when you reply. Mail sent from a connected account leaves through that account's own provider using their sending credentials, rather than through us pretending to be them. That keeps SPF, DKIM and DMARC aligned, which is the difference between a reply that arrives and one that lands in spam because the authentication didn't match the address.
Detection handles most of the setup, since IMAP is the same protocol everywhere. Given an address and a password, the common providers are recognized and configured without you looking up server names, and the ones that aren't can be entered manually.
The Gains That Are Real
What four providers, one inbox buys you is smaller than the phrase suggests, and more useful than it sounds too.
One place to look. The obvious one. Four providers, one inbox means the morning check is a single window rather than four tabs, three of which you forget on a busy day.
Search across everything. The bigger benefit in practice. Finding the message where something was agreed, without first remembering which account it arrived on, is the thing that saves real time.
One set of filters. Rules apply across connected accounts rather than being configured separately in each provider's own interface, each with different capabilities and none of them pleasant.
One second factor. You authenticate to us; the connected accounts are held by us. That's a convenience and a consideration, and it's covered below.
Still the Remote Provider's Problem
Being clear here prevents the most common disappointment with four providers, one inbox, which is expecting a connected account to behave like a hosted one.
The remote provider's rules still apply. If their storage is full, mail bounces there and nothing on our side changes that. If they throttle IMAP connections, syncing is slower. If they impose a sending limit, your replies hit it. Four providers, one inbox changes where you read and write, not who runs the mailbox.
Some providers also require an app-specific password rather than your normal one, particularly where two-factor is enabled, and a few restrict IMAP entirely on their cheaper tiers. That last case can't be worked around, because there's nothing to connect to.
Deletion is worth understanding before you rely on it. Removing a message from a connected account removes it at the provider, because you're operating on their mailbox rather than a copy. That's usually what people want, and occasionally a surprise.
The Plan Limits
External accounts are capped per plan, and the numbers decide whether this pattern fits before anything else does.
| Plan | External accounts |
|---|---|
| Free | 0 |
| Starter | 5 |
| Pro | 10 |
| Agency | 30 |
Five covers most individuals comfortably. Ten covers somebody juggling several client relationships. Thirty is aimed at people whose job is other people's mail — an assistant handling several executives, or an agency reading shared addresses across a client book.
The free plan has none, which matters if you were planning to use it as an aggregator. It receives on its own domains and connects to nothing.
The Credential Question
Running four providers, one inbox means we hold credentials that can read those mailboxes, and it would be dishonest to skip past that.
For your own accounts this is the same trust you already extend by hosting mail here. For accounts belonging to someone else — a client's mailbox, an employer's — it's a different question, and the right answer is usually to ask rather than assume. Some organizations forbid it outright, and finding that out afterwards is unpleasant.
Where you can, use an app-specific password rather than the account's main one. It's revocable on its own, it opens nothing else, and it gives the account owner a clean way to withdraw access without changing their password everywhere. That's good practice generally and particularly here.
When to Migrate Instead
Connecting is not always the right answer, and for a mailbox you'll keep indefinitely it usually isn't.
If an account is genuinely yours and you're paying for it somewhere else, moving the mail across and closing the old account is simpler, faster and cheaper than connecting to it forever. Four providers, one inbox is for mailboxes you can't or shouldn't move — a client's address, an employer's, one tied to a service you don't control.
The distinction is ownership rather than convenience. Anything you could close, close, and bring the history with you — that's what migration is for. Anything you can't close, connect.
A reasonable middle position is connecting first and migrating later. It costs nothing to connect, you find out quickly whether the account matters enough to consolidate, and the decision gets made with information rather than in advance.
Setting It Up Sensibly
A few practical points come up repeatedly when people set up four providers, one inbox.
- Connect the busiest account first and live with it for a week before adding the rest. If something about the arrangement doesn't suit you, better to learn it once.
- Check the reply address on the first message you send from each connected account. Replying as the wrong identity is the classic error and it's visible to the recipient.
- Expect the first sync to take a while on a large mailbox. It's fetching years of mail over IMAP, and the remote provider decides how fast.
- Watch for app-password requirements. A connection that authenticates and then stops is nearly always this.
Where the accounts you're consolidating are shared with colleagues rather than personal, the better mechanism is often a shared mailbox rather than several people each connecting to the same remote account with the same credentials.
