A Random Name or One You Choose

Stage: the name of the address. In control: you.

1. One question decides it, and it is not about convenience

A random name is harder to guess and a chosen name is easier to work with, so the choice comes down to a single question: does anybody have a reason to sit there trying names on this domain? If the answer is no, take the readable name and get on with your day. If the answer is yes, or if you cannot tell, take the long random one, because the cost of the readable name is paid by somebody guessing it and the cost of the random one is only that you have to paste it instead of typing it.

Everything below is the reasoning behind that sentence. There is no third option hiding in here and no setting that gives you both properties at once.

2. A chosen name buys recognition and nothing else

What you get from typing your own name is the ability to tell one mailbox from another. With three or four addresses open at the same time, a random string is unreadable at a glance while invoice-test and newsletter-test are not. If you are walking somebody through a scenario, or checking how a system behaves with several participants, names that mean something turn a screen of noise back into something you can follow.

The second thing it buys is that the address can be spoken. Dictating twelve random characters over a phone line goes badly. Dictating two ordinary words does not.

3. A chosen name pays for that with the length of the name

Here is the mechanism the recognition costs you. A guest mailbox on this service has no password: it opens for whoever knows the address, and that is the design rather than an omission. The name is therefore the only thing standing between the mailbox and a stranger, and a short dictionary word is not much of a thing to stand there.

That is not an alarm, it is arithmetic. If the name is a common word, then anybody working through a word list on this domain reaches it eventually. If the name is twelve characters drawn from letters and digits, the same list is useless and the attempt turns into brute force against a service that is not obliged to answer quickly.

4. The number of possible names grows with length, not with cleverness

The size of the space is set by two numbers: how many characters the name has and how many characters were available at each position. Six lowercase letters is a smaller space than twelve characters of mixed letters and digits by a margin so large that no amount of cleverness in the choice closes it. Picking an unusual word does not help, because the attacker is not guessing the way you chose, they are enumerating.

This is why the practical advice is boring. Do not look for a rare word. Add characters. A name that is four characters longer is worth more than a name that is more imaginative, and it costs you nothing except the difference between typing and pasting.

5. The name has no effect on whether the form accepts the address

Whatever you call the mailbox, a site that refuses disposable addresses is deciding on the part after the at sign. The left half is not consulted. A carefully ordinary name will not get you past a refusal, and a wall of random characters will not cause one.

The exception is the sort of form that rejects long local parts or unusual characters out of its own strictness, and that is a different problem with its own rules, laid out in what actually counts as a valid address.

6. Some situations make the chosen name the right call

Three of them come up often enough to name. A scenario with several participants, where you need to know at a glance which mailbox is the buyer and which is the seller. A demonstration in front of somebody else, where a random string reads as noise and undermines what you are showing. And any situation where the address has to leave the screen and travel through speech: read out at a counter, spelled into a phone, written on paper.

In all three the mailbox is short-lived and unattractive to guess, and the readability is what you are actually buying. That is the trade working in your favour rather than against it.

7. Your real name is the one thing the name must never contain

Do not put your own name, your surname or the handle you use elsewhere into a disposable address. This is the mistake that undoes the entire point of generating one.

An address containing the nickname you have used on forums since 2011 ties this signup to every other place that nickname appears, exactly as effectively as using your permanent address would have done. The mailbox is disposable; the string is not, because the string is now sitting in somebody's database next to whatever else you typed into that form. If the name is meant to mean something to you, let it mean something about the task and nothing about you: sofa-delivery tells you which mailbox this is and tells a stranger nothing.

The handover

Once the name is settled, the address is finished and control leaves you again. It passes to the service's pool while the mailbox lives, and it passes to nobody at all once the mailbox is gone, which is the situation that decides what a stranger could ever see. Before that, the first thing to meet your new address will be the browser, and the checks it runs on the way in explain most of the refusals people blame on the name. If you are about to make several addresses rather than one, the question shifts to keeping track of the ones you make, and the mechanics of the string itself are in how the generator assembles it. Both options, random or typed, sit on the same page where the address is made.