On a Phone

Most of the situations that call for a disposable address happen on a phone: airport wifi, a shop in a queue, an app that demands an account before showing anything. The mechanics are the same as on a computer, but two things make it easier to get wrong.

Never type the address by hand

The single biggest cause of a message that never arrives is a mistyped address on a small keyboard. One wrong character and the message goes somewhere nobody is watching.

Use the copy button. It puts the exact address on the clipboard, and pasting it into the other app takes one long press. This eliminates the entire category of problem and takes less time than typing.

If you find yourself needing to remember an address rather than paste it, type your own name into the field instead of accepting a random one. Something you will recognise later is much easier to retype correctly if you must.

Switching apps does not lose your mailbox

Leaving the browser to open another app is fine. The mailbox is tied to your browser, not to the tab staying in the foreground, and it is still there when you come back.

What does lose it:

Clearing browsing data. The identifier that links you to your mailbox lives in browser storage. Clearing it means the site no longer knows which mailbox is yours, and it will hand you a new one. The old mailbox and its contents expire on their own shortly afterwards.

Private browsing. A private tab discards its storage when you close it. Open the site in a normal tab if you need the address to survive.

A different browser. Your mailbox lives in the browser you created it in. Opening the site in another one gives you a different mailbox.

Waiting for a message

Return to the tab and leave it open. The inbox updates by itself as soon as anything arrives, so there is nothing to pull down or refresh. A verification code usually appears within seconds of being sent.

If the phone locks or the browser suspends the tab in the background, the connection may drop. Bringing the tab back to the foreground reconnects it and loads anything that arrived while it was asleep, so nothing is missed.

Reading a message

Tap it to open. The message opens inside the page in an isolated frame, which is why it can look slightly plainer than it would in a mail app. Scripts are disabled and the message cannot interact with the rest of the page, which is the point.

Wide marketing templates sometimes need horizontal scrolling on a narrow screen. That is the template's doing rather than ours: many are built for a desktop window and never tested anywhere smaller.

The mistake to avoid while waiting

Do not press for a new address because nothing has appeared yet. That deletes the mailbox the message is on its way to, and there is no way to get it back. Wait a minute or two, and if nothing arrives, read the page about codes that do not turn up rather than pressing the button.

Moving between two devices

The common case: the signup form is on a laptop, and you want the code on your phone, or the other way round.

The mailbox belongs to the browser that created it, so the second device does not have it automatically. Two ways round that.

Read on the device that has the mailbox. Simplest. Get the address on the laptop, paste it into the form there, and read the code there too. The phone is not involved at all.

Type the address on the second device. Guest mailboxes are open by address: enter the same address on the phone and the same messages appear. This is why choosing your own name matters, because retyping a random address on a phone keyboard is where mistakes happen.

Note the trade this relies on: if you can open a mailbox by typing its address, so can anybody else who knows it. For a verification code that is fine. For anything else, register, and then the mailbox is genuinely yours.

Battery and background behaviour

Phones aggressively suspend tabs that are not in front. When the tab wakes up, the connection reopens and anything that arrived meanwhile appears.

What this means in practice: leave the tab in the foreground while waiting for a code, and switch away freely once you have it. If you come back to the tab after a long time and it looks empty, give it a second to reconnect before concluding that nothing arrived.

Mobile networks also sometimes interfere with long lived connections. If the indicator says it is reconnecting for more than a few seconds on a shaky connection, reloading the page is faster than waiting.

Autofill will offer your real address

The keyboard is not the only thing that can put the wrong address into a form. As soon as a field is recognised as an email field, the browser or password manager suggests the address you use everywhere, one row above the keys, exactly where your thumb already is.

One accidental tap and the signup you were being careful about has your real address in it. Worse, some forms submit on the next tap, so there is no moment where you notice.

Two habits remove this. Paste first and look at the field afterwards, since a pasted value is not replaced by a suggestion. And when a form is prefilled on arrival, clear it deliberately rather than typing over it, because a partially overwritten suggestion is how half of one address ends up joined to half of another.

The reverse mistake also happens: your password manager offers to save the temporary address as a new login. Declining keeps your saved entries meaningful a month later, when the address itself is long gone.

Signups that happen inside an app

Tapping a link in a chat or social app usually opens a stripped down browser inside that app rather than the browser you use. It has its own storage, which means it has its own mailbox.

The consequence is the same one as clearing browsing data: an address obtained in your normal browser is not there, and an address obtained inside the app view may be discarded when the app closes it. People end up with a code sitting in a mailbox they cannot find again.

Most of these views have an option, in a menu or a share sheet, to open the page in the real browser. Use it before starting a signup, and everything stays in one place.

Adding it to your home screen

If you use this often, most mobile browsers let you save a page to the home screen. It opens in the same browser context, so your mailbox is the one you already had, and it saves finding the site every time.

One caveat worth knowing: on some browsers a home screen shortcut runs in a separate storage context, which means a different mailbox from the one in your normal tabs. If the address looks unfamiliar after adding the shortcut, that is why, and using the shortcut consistently from then on keeps everything in one place.