I understand that it's long been a tradition in American fictional works, especially movies and TV, to use a '555' phone code for any numbers that needed to be displayed on-screen, as that prefix doesn't exist, and so there was no risk of the writers unwittingly using a real number.

As a writer of stories, my question is: Are there any similar non-existent or otherwise reserved top-level domains that I could use in a fictional context to avoid inadvertently publishing an in-use—or a 'likely-to-come-into-use'—domain?

I'm aware that TLDs are being created a lot more quickly than they were, but I didn't know if there were any specifically set aside.

As additional info, my current project is an alternate history story set in a modern-day Roman state, so I'd ideally be looking for a TLD I could crowbar into representing that in some way. I did consider .spqr as a sort of equivalent to .gov, though that's maybe a little heavy-handed setting-wise (but of course that's for me to figure out...).

I've also checked this list at ICANN, and I can't see, for example, .spqr or .rom. I'd be cautious about using them if they're potentially available for future registration.

EDIT 23/Jan/17: Wow. I'd like to thank everyone who's taken the time to reply to this. I really do appreciate it, and there have been some great suggestions. I think, on balance, probably the easiest way to go is, as some have said, to simply come up with a new format for addresses, on the assumption that in my alternate history many things will be different, some subtly, some less so - so this might as well be one of them.

Even so, there have been some great ideas, and some interesting info provided. I'm still going through some of the comments as I have chance - please forgive me if I don't answer them all!

Again, thanks for taking time to offer these suggestions.

  • 4
    $\begingroup$ At this point of time, any organisation with an appropriate justification and money can probably register any TLD. Might be worth considering non standard protocols and slightly and carefully different domain systems instead. Does feel vaguely like it could belong elsewhere, but its almost bedtime so I'll let the community or other mods decide. $\endgroup$ Commented Jan 21, 2017 at 15:23
  • 3
    $\begingroup$ The canonical list of reserved TLDs is BCP 32. Unfortunately, none of them are ideal for fiction. Perhaps you'll get better responses at Writing (you can request mod migration of the question). Journeyman Geek's suggestion is a good one, if it works with your universe (i.e. anything but modern-day Earth) -- invent a new naming system that looks close enough to be familiar but is otherwise invalid, e.g. using colons instead of dots. $\endgroup$
    – Bob
    Commented Jan 21, 2017 at 15:26
  • 2
    $\begingroup$ This would be good on writers.stackexchange.com - I can't see how this is world building, it is about describing parts of the world / story in a way that won't cause real life issues. $\endgroup$
    – Mołot
    Commented Jan 22, 2017 at 12:44
  • 7
    $\begingroup$ @Mołot I disagree. This is about basic construction of an element of a fictional world, which is what Worldbuilding is about, only with the additional constraint that it mustn't cause conflicts with the superficially very similar system in the real world (which serves to establish the parameters of the question, just like how "give me a real-world-science explanation for how X could happen in my fictional world" does). Writing is essentially about how to write at levels larger than paragraphs or thereabouts, so this would be squarely off topic there. $\endgroup$
    – user
    Commented Jan 22, 2017 at 16:11
  • 2
    $\begingroup$ Actually, 555 is not reserved in any standard. Many phone companies voluntarily avoid numbers using it, but not all of them. Real phone numbers that of the form 555-xyzw do exist. $\endgroup$
    – KRyan
    Commented Jan 22, 2017 at 19:31

16 Answers 16


Register a real domain

You could think about registering a real domain (with a name relevant to your novel) and then:

  • Adding some real content that either is an optional part of the story or

  • Adding content that promotes your work.

The following links provide complete instructions on how to register a domain name.

Register a new Top Level Domain

Several comments have suggested creating a new TLD (Top Level Domain). This is not recommended because:

  • It's nowhere near as easy as registering a second or third level domain and comes with significant extra responsibilities.

    The application for a new gTLD is a much more complex process. An applicant for a new gTLD is, in fact, applying to create and operate a registry business supporting the Internet's domain name system. This involves a number of significant responsibilities, as the operator of a new gTLD is running a piece of visible Internet infrastructure.

  • It is very expensive.

    The evaluation fee is USD 185,000. Applicants will be required to pay a USD 5,000 deposit fee per requested application slot when registering. The deposit will be credited against the evaluation fee.


    Once an application has successfully passed all the evaluation steps, the applicant is required to sign a New gTLD Agreement (also called Registry Agreement) with ICANN. Under the agreement, there are two fees: (a) a fixed fee of USD 6,250 per calendar quarter; (b) and a transaction fee of USD 0.25. The latter does not apply until and unless more than 50,000 transactions have occurred in the TLD during any calendar quarter or any four calendar quarter period. Please refer to section 6.1 of the New gTLD Agreement in the Applicant Guidebook.

Source Frequently Asked Questions

  • 8
    $\begingroup$ Creating a top-level domain is eyond the capability of most individuals. $\endgroup$
    – JDługosz
    Commented Jan 21, 2017 at 16:05
  • 11
    $\begingroup$ @JDługosz Beyond the ability of most individuals, yes, but we don't know what resources the author has at his/her disposal. Or future readers of this question. As for godaddy ads, I've never figured out how a woman's breasts are used in DNS protocols, but I'm sure there's a man page for that somewhere. $\endgroup$
    – SRM
    Commented Jan 21, 2017 at 16:15
  • 6
    $\begingroup$ @JDługosz I'm proposing a real domain not a TLD. $\endgroup$ Commented Jan 21, 2017 at 16:28
  • 29
    $\begingroup$ @JDługosz The TLd in the question is just a means to an end - making sure that the domain doesn't exist in the real world. This answer provides an alternative: making sure that the domain does exist in the real world and that the author has control over its content. $\endgroup$
    – Polygnome
    Commented Jan 21, 2017 at 21:47
  • 2
    $\begingroup$ @spark I deliberately did not suggest that because "An applicant for a new gTLD is, in fact, applying to create and operate a registry business supporting the Internet's domain name system. This involves a number of significant responsibilities, as the operator of a new gTLD is running a piece of visible Internet infrastructure." with a significant cost attached (~$370 for an application). $\endgroup$ Commented Jan 22, 2017 at 12:06

Several people have suggested the possibility of using real-life reserved domain names. (For those curious, I have a summary of names and networks reserved for examples and documentation on my personal web site.)

Some people have even suggested using real-world domain names that are somehow undesirable, but still valid.

Yet others have suggested to register a domain name of your own, such that you are able to control its content.

I'm going to go out on a limb and suggest that there is a way to make up valid-looking domain names that actually will not exist.

That's because the two-letter top level domains are ISO 3166-1 alpha-2 country or territory codes. (ruakh pointed out in a comment that there exist exceptions to this rule. See below.)

Wikipedia has a handy table of assignment status of all such code combinations.

There are four ranges that are "free for assignment at the disposal of users" and thus, barring a major rework of the ISO standard, cannot possibly become valid top-level domains. Those are AA (just that one), QM through QZ, XA through XZ and ZZ (just that one).

The same Wikipedia article also has a short list of examples how some of these are currently being used. There are also a large number of codes reserved but not free for assignment for various reasons and varying lengths of time.

Basically, if you compose a domain name like you normally would on the Internet,

  • but give it a top-level domain out of the ISO 3166-1 alpha-2 "free for assignment at the disposal of users" range, then you can be all but certain that it will not clash with any real-world Internet domain name now or in the future.
  • but use any of the other ISO 3166-1 alpha-2 reserved combinations for a TLD, then you have to check to make sure that you aren't causing a potential name conflict (for example, EU is "exceptionally reserved", and is actually available as a top-level domain), but for the most part you should be okay.

So it's perfectly possible for your character to have an email address like [email protected] and you can be as certain as one can reasonably be that nobody will be registering the domain name momandpopwebmail.qw for use on the actual Internet. (Maybe "QW" means "quickweb" in your world?)

Always ISO 3166-1 alpha-2?

As was pointed out by ruakh, citing .uk as an example, there are a small number of country-code top-level domains that do not match the country's ISO 3166-1 alpha-2 country code, which in this case is GB.

The criteria for eligibility for a two-letter ccTLD are laid out by the Internet Assigned Numbers Authority (IANA). There are a few other exceptional cases allowed for, but the main exception is for ccTLDs that do not match the country's alpha-2 code, but were originally approved before 2000 under an exceptional delegation in ISO 3166 and still maintain that status:

  • Grandfathered prior to 2000. ICANN codified the rules under which future exceptionally reserved delegations may be considered in 2000 in Resolution 00.74. Certain domains were delegated on the basis of being “exceptionally reserved” by the ISO 3166 Maintenance Agency prior to this date. These domains were “.UK”, “.AC”, “.GG” and “.JE”. Of these, “.GG” and “.JE” are now listed in the ISO 3166-1 standard and therefore qualify normally. The remaining two domains that are grandfathered under their original eligibility are “.UK” and “.AC”.

It's worth noting in relation to ruakh's example of the United Kingdom that the Internet Corporation for Assigned Names and Numbers (ICANN) lists .gb as "unassigned, reserved" and "originally meant to replace .uk". We also note that Wikipedia's summary table lists both AC and UK as "exceptionally reserved".

Because the rule quoted above is about the eligibility of ccTLDs that were established before the current rules for ccTLD eligibility took effect in year 2000, barring an IANA rule change, no new ccTLDs can be assigned under the grandfathering criteria. While not exactly an ISO standard, these rules do on the Internet have status similar to that of an ISO standard.

Since none of the "free for assignment at the disposal of users" ISO 3166-1 alpha-2 codes fall under the grandfathering rule, and no other eligibility criteria appear to apply, we can still safely use those ranges confident in our assessment that they will not be assigned as top-level domains.

What about two-ASCII-letter TLDs not covered by ISO 3166-1 alpha-2?

This is covered by Internet Corporation for Assigned Names and Numbers (ICANN) Resolution 00.74, which states that (my emphasis):

It is therefore RESOLVED [00.74] that the IANA staff is advised that alpha-2 codes not on the ISO 3166-1 list are delegable as ccTLDs only in cases where the ISO 3166 Maintenance Agency, on its exceptional reservation list, has issued a reservation of the code that covers any application of ISO 3166-1 that needs a coded representation in the name of the country, territory, or area involved;

The "advised" is a bit of a red herring here; it means "we are telling you that", not "we are suggesting that". The operative part specifies that "alpha-2 codes not on the ISO 3166-1 list" can be assigned as ccTLDs only in the case that said code has a status of "exceptional reservation". As a consequence, the set of TLDs described by "alpha-2 codes" (two English alphabet characters) is restricted to the meaning that those character combinations have in ISO 3166-1 alpha-2.

But... but... what about in the future?

Sure, things can change. But at this level, things change very slowly. Given how many different entities likely use the "free for assignment at the disposal of users" ISO 3166-1 alpha-2 ranges for their internal use, were the relevant ISO committee to start to assign those codes for other uses, all hell would break loose. If these codes are ever to be assigned to any other use, there would likely be a decades-long transitionary period preceding it. Compare the current transitional reservations which in several cases stretch out to the 2050s, still a good 30-40 years into the future.

Also note that a good half or so of the alpha-2 codes are as of yet unassigned. Should a new country appear tomorrow that is sufficiently recognized to receive its own ISO 3166-1 alpha-2 code, it is likely that an appropriate two-letter code could be selected without needing to do anything with the ranges that are specifically available for users' own use.

We also note that the Frequently Asked Questions for the gTLD application process as published by the ICANN specifically states that (my emphasis)

2.12 Can a New gTLD name be 2 letters?

Applied-for gTLD strings in ASCII must be composed of three or more visually distinct characters. Two-character ASCII strings are not permitted, to avoid conflicting with current and future country-codes based on the ISO 3166-1 standard.

On the whole, I wouldn't worry about the risk of collions between future assigned TLDs and the "free for assignment at the disposal of users" ranges in ISO 3166-1 alpha-2. If it ever happens, your story might even become a bit of international relationships history.


  • Use a two-letter top-level domain of AA, QM through QZ, XA through XZ or ZZ.
  • $\begingroup$ Isn’t that out of date? Or rather, another channel coding on top of that is implied for normally written URLs so that they contain non-ASCII characters now. In my Answer I assumed this (A-Z only) was still the case for top level, but you’re talking about “any part”. $\endgroup$
    – JDługosz
    Commented Jan 21, 2017 at 23:26
  • 11
    $\begingroup$ Labels certainly can start with digits; current examples include 3m.com and the entirety of in-addr.arpa. I believe RFC1123 first relaxed that definition in 1989. $\endgroup$ Commented Jan 22, 2017 at 2:14
  • 1
    $\begingroup$ @MichaelHomer You are perfectly correct. I have no idea how I could completely forget about in-addr.arpa. Fixed! $\endgroup$
    – user
    Commented Jan 22, 2017 at 11:27
  • 1
    $\begingroup$ @GrantDavis Actually registering the domain is the basis for DavidPostill's answer. My answer provides a way to make a plausible-looking domain name that (barring major world upheaval) cannot possibly exist on the real-world Internet. Both are perfectly valid approaches, and which you choose depends very much on the result you are after. $\endgroup$
    – user
    Commented Jan 22, 2017 at 16:04
  • 1
    $\begingroup$ @nigel222 "one or more organisations out there using them on its internal nameservers" It isn't just about DNS, but lots of other uses as well. Country and territory codes are used in places that aren't readily obvious. Consider that currency symbols are often (always? I can't think of any counterexample off the top of my head.) made up of the two characters of the 3166-1 alpha-2 country code followed by one more character: USD, GBP, EUR, DEM, NOK, ... There are also pseudo-currency-symbols like XAU (gold, Au), XAG (silver, Ag) which match this pattern because XA is reserved for custom use. $\endgroup$
    – user
    Commented Feb 1, 2017 at 13:53

As mentioned by @journeyman-geek, you might consider giving your world an alternative name resolution system which avoids collision by not following the format of domain names as seen in our own DNS system. This is easy to imagine as the defining features of modern DNS names (and, by extension, URLs) are largely historical accident.

For example, many email addresses in the Ender's Game series look like hgraff%[email protected]. A % sign in the email address was used by various network gateways such as the CSNET relay, something which was common at the time the first Ender books were written but is unheard of today.

One such possible scheme could be to reverse the hierarchical order and use colons instead of periods, yielding a format such as spqr:senate:marcus·tullius·cicero. (Note also the interpunct, an obscure character in the English alphabet but one which I assume was likely included in basic RSCII and allowed in their DNS names.)

  • 3
    $\begingroup$ Along similar lines, consider changing the protocol. URLs in the WebMage (Ravirn) series are of the form "Mtp://mweb.DecLocus.prime.minus3051/umn.edu" ("M" presumably stands for "multiverse"). $\endgroup$ Commented Jan 22, 2017 at 4:22
  • 3
    $\begingroup$ Great idea. In one of William Gibson's cyberpunk stories, I recall a character logging in to a website which was specified in-universe as "fetish:footage:forum" or something like that. Be creative, come up with your own naming system. Robert Columbia, email\rcolu/comsystem-stackoverflow $\endgroup$ Commented Jan 22, 2017 at 23:17
  • 1
    $\begingroup$ The interpunct is an awesome idea! $\endgroup$
    – TRiG
    Commented Jan 23, 2017 at 10:37
  • 1
    $\begingroup$ @PeterGreen Yeah, I looked up the relevant RFCs and was surprised to find just how complex email addresses can get. On the other hand, vwiggin%[email protected]/citizen definitely isn't valid, and I can't find a historical precedent, either. (Also, people change their email addresses a lot in the Ender universe. How do they keep track?) $\endgroup$
    – Wolfgang
    Commented Jan 23, 2017 at 17:21
  • 1
    $\begingroup$ Regarding reversing the order of the labels, that was done on Usenet (where, for example, sci was subdivided into sci.astronomy, sci.space and so on; thus looking roughly like a reversal of DNS names), and on FidoNet (where you would have an address like 1:234/999.12345 where 1 specified the continent, 234 the area, 999 a system, and 12345 (optional) specified a user connected to that system). A long time ago, back in the glory days, I had a FidoNet address of 2:201/204.4 -- I remember that I specifically asked the owner of the node 2:201/204 for a low point number. $\endgroup$
    – user
    Commented May 29, 2017 at 19:28

Nothing that would really work - as per bob's excellent comment, there's a list of reserved, example TLDs, none of which are suitable and the new gTLDs are pretty broad.

There's nothing stopping a organisation with a justification and enough money from registring any new gTLD.

Its worth considering the rich and varied tradition of making things up when talking about computers in media, from interfaces to websites.

As such the 'clever' way would be to introduce some slight, subtle inconsistancy.

555 was picked so it wouldn't route to any phone number

You could simply pick a branch of the multiverse where things went differently, colons instead of dots, or even having your network as one large set of directories.

So the office of the imperitor general of the imperial sanitation department might be at spqr/sanitation/org/official/imperitor.

This would break in any modern web browser and would be consistant.

Or just gloss it over and tell, don't show.

  • 5
    $\begingroup$ If you had directories, the TLDs would be at the top - so org/sanitation/spqr/official/imperitor, rather than spqr/sanitation/org/official/imperitor. $\endgroup$
    – ArtOfCode
    Commented Jan 21, 2017 at 15:52
  • $\begingroup$ Its late, and I was completely making this up as I go along. ;p $\endgroup$ Commented Jan 21, 2017 at 15:53
  • $\begingroup$ With that in mind, you don't even need directories for the domains, you can still use periods and not have it conflict with any website: org.sanitation.spqr/official/imperitor $\endgroup$ Commented Jan 21, 2017 at 15:54
  • 1
    $\begingroup$ @Miguel that's what the OP wanted to avoid in case spqr becomes a valid TLD at some point. $\endgroup$
    – Bob
    Commented Jan 21, 2017 at 16:00
  • 5
    $\begingroup$ Great point suggesting to "tell, don't show". "Brutus hastily typed in the website address of the Imperial Roman Zoo Inspection Service that had been written on the back of the pizza receipt, swearing under his breath about the awkward keyboard that the machines of Londinium usually had." The fewer details you give, the fewer details there are that can become out of date. Let your readers decide what a Roman Zoo Inspection Service website address looks like and what might have been awkward about Londinium keyboards. $\endgroup$ Commented Jan 22, 2017 at 23:28

There is the tTLD (test top-level domain) class of domains, like .test (see https://en.wikipedia.org/wiki/.test or RFC 6761 from February 2013, section 6.2), the same in various scripts and common languages for that script (https://en.wikipedia.org/wiki/Top-level_domain#IDN_test_domains).

RFC 2606 from June 1999, section 2 also mentions .test and additionally:

  • .example
  • .invalid
  • .localhost

with the following explanation:

  ".test" is recommended for use in testing of current or new DNS
  related code.
  ".example" is recommended for use in documentation or as examples.
  ".invalid" is intended for use in online construction of domain
  names that are sure to be invalid and which it is obvious at a
  glance are invalid.
  The ".localhost" TLD has traditionally been statically defined in
  host DNS implementations as having an A record pointing to the
  loop back IP address and is reserved for such use.  Any other use
  would conflict with widely deployed code which assumes this use.
  • 3
    $\begingroup$ That list of test names is specifically not of interest to the OP! It needs to be realistic in his context, not obviously a testing name. $\endgroup$
    – JDługosz
    Commented Jan 21, 2017 at 23:28
  • 3
    $\begingroup$ To future authors: please don't pick any of those TLDs. $\endgroup$
    – isanae
    Commented Jan 22, 2017 at 2:42
  • 6
    $\begingroup$ One could retcon the meaning of one or more of these domains. For example, ".test" could be defined within the story to be an acronym of "Trans-European State Territory", a formal name for a political entity existing within the universe. Similarly, one could observe that the word "host" can also mean "army", so ".localhost" could be defined as as top level domain name for "local" (e.g. as opposed to regional or national) military installations, forts, etc. $\endgroup$ Commented Jan 22, 2017 at 23:08
  • 1
    $\begingroup$ Going with my "localhost" idea, the centurion in charge of the western half of Hadrian's Wall might be addressed in the network as "[email protected]". $\endgroup$ Commented Jan 23, 2017 at 17:52
  • 2
    $\begingroup$ As a software guy myself, "localhost" is heavily ingrained as a special identifier with a specific meaning, and it would be very difficult to maintain the fiction. The word "test" could plausibly be used, as above, but still only with great care. $\endgroup$
    – Phlarx
    Commented Jan 25, 2017 at 17:22

If your world allows, your world's Internet doesn't work the same.

If you create your Internet to use underscores, a certain character, or a character you invented instead of a period, then you can have whatever address (if your new Internet uses addresses) you want.

Or you could do away with top and sub domains all together. For example you could have John Doe's email address be:


And have the search engine address be:


This is pretty future proof, because top and sub domains aren't going anywhere.

Those were some ideas, you could get creative with your new Internet.


As part of the general idea of making something that would not be a legal TLD (as o.m. notes), you could have a character not found in ASCII as part of the TLD. The development turned out a little different in your universe.

This could work especially well if the alternate history skipped something that was responsible for one of our modern letters, so of course that would be different.

Using a real (historical) letter has the advantage of being able to type and print it: (Þ, þ) is one of my favorites. Or maybe they kept some that look more like the Greek progenitors (Γ instead of C) or G is still a C with diacritical mark.

I think it would be interesting if one such change were present in names and such; not so much as to baffle the reader, but just one difference to give it a unique character [pun intended].

With internationalized domain names now, mixing scripts from different languages (like using Γ for C but otherwise Latin characters) is unlikely to match any future domain name, which will be in one language or the other but not mix languages in the same word.

If the book is self-published and you’re providing print-ready PDF, you could make your own unique character. But it’s quite hard to invent something suitable as a letter that’s not already real (and hopefully in Unicode).

Much of the URI syntax is “just the way it turned out” and it could easily have been different. I recall reading that Tim Berners-Lee considers the current system inconsistent with the hostname backwards from the path, and use of different separators is unnecessary. So www.example.com/site/page#fragment should really be com.example.www.site.page.fragment. Point is, in an alternate history you will expect the syntax to be different in detail, even if they hit upon the same general idea of a uniform resource locator as a hiarchy that extends a machine’s directory structure.

You might use a different (or different looking) character as the separator, such as a tiny superscript ^ or a vertical bar that spans the whole ascender through decender height of the character cell.

  • $\begingroup$ They would be possible in i18n domain names. You would need to do so in a TLD which doesn't include those characters in their whitelist. $\endgroup$
    – Ángel
    Commented Jan 22, 2017 at 3:18
  • $\begingroup$ TLD is what I’m referring to. $\endgroup$
    – JDługosz
    Commented Jan 22, 2017 at 4:30
  • $\begingroup$ I like this idea :Þ $\endgroup$ Commented Jan 22, 2017 at 23:20
  • $\begingroup$ The letter þ is very much in use. Compare Eyþór Ingi Gunnlaugsson, an Icelandic singer who participated in the Eurovision Song Contest 2013 with the song Ég á líf. $\endgroup$
    – user
    Commented Jan 24, 2017 at 14:15
  • 1
    $\begingroup$ I'd suggest replacing the periods and--if applicable--the at-sign with some other character. For example james~kirk≗enterprise≛starfleet≛ufp. That should avoid any conflict with actual addresses even if there were an actual ufp domain. $\endgroup$
    – supercat
    Commented Jan 24, 2017 at 19:40

You can use the system most countries that are not the USA use. Combining the TLD for the purpose of the website with the country's TLD

For example the website for the praetorian guard would be: www.praetorian-guard.gov.rom or www.praetorian-guard.gov.spqr while a normal website would be along the lines of www.pizza.com.rom or www.pizza.com.spqr.

That way, even if the TLD .spqr or .rom are registered as a gTLD, the websites would not exist because such format is only used for regular TLDs. And it's not like a new country will just appear and claim .spqr or .rom anytime soon, if ever.

  • 2
    $\begingroup$ Note that any TLD can be now created by a (well-endowed) company or entity. For example: .run, .room, .sony, and .alpharomeo are all actual TLDs today. $\endgroup$ Commented Jan 21, 2017 at 23:27
  • 5
    $\begingroup$ If .spqr were registered as a gTLD, wouldn't that allow the owner of .spqr to register (or sell to someone else) the domain name com.spqr, allowing someone to get pizza.com.spqr as a subdomain? $\endgroup$ Commented Jan 22, 2017 at 16:39
  • $\begingroup$ @TannerSwett: yes, if the gTLD operator wants to. As it happens, there's 130 TLDs with com as a public suffix immediately under them: com.ac, com.af, com.ag, etc. At the moment all of them are country(-like) TLDs, but I don't think it's out of the question for a gTLD operator to do the same. Really it's just a matter of whether they think there's demand for yournamehere.com.spqr: if so then they can put in place a system to register such names. It would be bad luck for the author who used it as a "fake" domain name, but avoiding such bad luck is what name registration is all about! $\endgroup$ Commented Jan 24, 2017 at 21:06

How about something that would not be a valid domain name, but looks roughly like one?



Reserved ones are things like .test or .invalid, they stand out in a story.


FYI Rome's actual institutional website domains are:

  • www.comune.roma.it (literally"common".rome.it)

  • www.cittametropolitanaroma.gov.it (lit. "metropolitan city of rome".gov.it)

I live there & I would incredibly love to see the '.spqr' in such a story. Anyways, I don't believe that domain name will ever be added (never say never: angry spanish people got .cat domain).

Anyways consider this: if the Roman Empire survived 2300 years they would have developed other ways to describe domains. But, because you are the author and people (or nerds?) expect a normal-looking domain name you could just flip the entire name like java packages or similar dot-separated syntax.

There would not be an international standard as the emperor ands senators would have it very roman-centric, i think maybe a sort of directory-like nomenclature for websites, where every website would be given an unique domain name by the Pontifex (or his office).

There would be an hyper textum translationis protocollum using that to fetch resources for users.

For example one of the few approved search engines, the Google Indagator, is reachable here: http://spqr.indagator.google. Here is Ceasar's memorial website: http://spqr.historia.caesar.

As romans sought to integrate other people in the empire they would eventually add something like: http://spqr.barbari.carthago.voluptuaria for websites about external countries (this specific one to have a family trip to the ruins of a famous city in Tunisia).

  • 1
    $\begingroup$ Note that .google is a real, existing, TLD. And the domain name com.google exists. $\endgroup$
    – TRiG
    Commented Jan 23, 2017 at 10:36

You could use a single-letter second-level domain in .com, .net, or .org, like y.com, or 1.org. There is more info on which TLDs won’t accept these in the Wikipedia article “Single-letter second-level domain”.

Another option would be to make up your own addressing scheme like:

  • $\begingroup$ @Anketam. There was actually text there but the Markdown formatting hid it by mistake. I've edited to make it visible. $\endgroup$
    – TRiG
    Commented Aug 7, 2019 at 11:20

a.com, b.com, c.com, etc.

In 1993, the Internet Assigned Numbers Authority (IANA) explicitly reserved all single-letter and single-digit second-level domain names in the top-level domains com, net, and org

Some were reserved before '93 and do actually have sites (i.net, q.com, q.net, x.com, x.org, z.com, a.co, g.co, t.co, t.me, w.org), but everything else is off limits.


In December 2005, ICANN considered auctioning these domains

So maybe these domains will be available someday. But it's been 11 years, so I wouldn't bite my nails about it.

Source: Single-letter second-level domain


Perhaps something quite different, like sort-of an X.400 address with different labels: nun=incudibus,dpca=acme,dap=com


There are reserved IP addresses

For example, routes back to your own computer, while 192.168.XXX.XXX addresses are reserved for internal use in private networks, as are the 10.XXX.XXX.XXX and 172.16.XXX.XXX blocks. You can safely use them as fictional addresses knowing that no-one on the internet has these addresses.

There are also some IP blocks reserved for documentation, namely 192.0.2.XXX, 198.51.100.XXX and 203.0.133.XXX.

IPv6 has the block 2001.bd8.XXXX.XXXX.XXXX.XXXX.XXXX.XXXX reserved for documentation, while fcXX.XXXX.XXXX.XXXX.XXXX.XXXX.XXXX.XXXX is for use in private networks.

Unfortunately they're not quite as punchy as domain names, although you can actually connect to IP addresses through your browser.



  • 1
    $\begingroup$ All the media I've seen which uses IP addresses as part of a dramatisation fudges the numbers so they're out of range (e.g. 324.192.87.44) $\endgroup$
    – moopet
    Commented Jan 24, 2017 at 9:52
  • $\begingroup$ Actually, those aren't so much reserved as specially assigned. (It wasn't always this way. NET-10, for example, IIRC was originally used for ARPANET administrative purposes, and was very much routable.) However, there are several blocks that are actually reserved specifically for examples and documentation. On my personal web site I have a list of Internet names and networks reserved for examples and documentation which you may find useful. I made it because the info is spread out in several RFCs. $\endgroup$
    – user
    Commented Jan 24, 2017 at 14:19
  • $\begingroup$ @Michael Kjörling : Thanks. I'll link that in my answer. $\endgroup$ Commented Jan 25, 2017 at 1:41

I don't believe there are any reserved names for authors. I know that Microsoft reserved some fictitious names themselves so perhaps that is a good example of what others do.


  • $\begingroup$ Hello and welcome to worldbuilding.SE! Maybe you could flesh out your answer a little bit, e.g. by taking the examples from that site, explaining where microsoft uses their fake-name and how this could be applied to the problem described in the question. Answers that mainly consist of a likn are rarely well received, especially because a link could be outdated at some point. If you want you can take the tour and view the help center to learn more about how answers and questions should be written. $\endgroup$
    – Secespitus
    Commented Jan 24, 2017 at 20:27

I stumbled upon this in 2022 and it occured to me that the trends of cctlds have changed a bit since 2017. For example, there is now .scot, .wales, .quebec, and .cat. So for a theoretical a modern day Rome a cctld of .spqr wouldn't be that odd after all.



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