How a one-sender inbox locks

A one-sender inbox is an address for one company or one person. It locks to the first of them to write, and bounces everyone else. If the address leaks, it's no use to whoever finds it.

Make one

1. In the sidebar, next to One-sender, select +. On a phone, select Inboxes at the bottom of the screen first.

2. Type a name for it, and select Create.
3. Give the address to the company or person it's for.

See who it's locked to

The inbox locks to the first sender whose address can be checked: the domain in their From line has to vouch for the message, with the checks email uses against forgery. What the lock keeps depends on who wrote:

• A company, by its domain. Mail from any domain of the same organization gets in, so news.northgatebank.example and northgatebank.example can both write.
• A person at Gmail, Outlook, iCloud or another shared provider, by their own address, such as ana@gmail.com. Nobody else there gets in.

To see who it is, open the inbox, then its settings with the gear at the top right, and look under Locked to. Until someone writes, it says Nobody yet.

Let someone else in

Anyone else who writes is turned away as their mail arrives. Their own mail server tells them it wasn't delivered, and nothing of it is kept here.

The reason they're given names the companies the inbox takes mail from, as in this inbox only accepts mail from northgatebank.example. It never names a person: an inbox locked to people alone says this inbox is locked to another sender.

To take mail from someone else too, add them to the lock: Let more senders into a one-sender inbox shows how.

Good to know

Mail that can't be checked doesn't lock it

It's still delivered, and the inbox waits for a sender whose address can be checked. Mail that goes to your spam folder never locks it either.

The first message brings one sender

It locks the inbox to its own sender and nobody else. You can let in up to five.

A person's address, exactly

To a lock, ana.tavares@gmail.com and anatavares@gmail.com are two senders, and so is the same address with a + in it.

The header says who

On a computer, an inbox's header says who it takes mail from, such as Only accepts northgatebank.example, or Not yet locked to a sender.

It doesn't expire

It takes mail until you switch it off, or give it an end date.