Tech Startup Domain Names

Name first, domain second

The most expensive habit in startup naming is letting a search box do the choosing. It optimises for one property (nobody has claimed this string) at the expense of every property that decides whether a name works: whether people remember it, whether they can spell it after hearing it once, and whether it means something unfortunate in a market you plan to enter. The names that come out share a family resemblance. Dropped vowels. A doubled consonant nobody expects. A suffix bolted on because the plain word was gone. Each is a permanent tax on word of mouth. The domain was free. The name was not. Run it in this order instead.

1. Generate candidates with no registrar openThe moment a search box is in front of you, availability becomes the only criterion, and it is the one property that has nothing to do with whether a name is any good.
2. Score the properties that never changeHow memorable a name is, how it survives being heard and typed, and what it means in your other markets are fixed features of the word. Sort on those first.
3. Take the top five to the market, not the top fiftyNow look up what is registered, and only for names that already earned a place. You are asking which good name is obtainable, not which free string you can learn to like.
4. Choose the extension lastIt is the smallest decision here: a suffix, changeable, and companies move between them routinely. Match it to the audience that reads it as normal, not to the one that was free.

Still generating candidates? The full process is in how to name a tech startup and the methods are in how to brainstorm brand names.

The best domain extension for a tech startup: what each one signals

An extension is a compression of information. Before anyone reads your headline, the suffix has told them what kind of company this is, and different audiences decode it differently. The question is never “which extension is best”. It is “what does this one say to the person I need to convince, and what am I taking on by using it”.

• .com
  Almost everything, if you can get itThe extension people type by reflex when they half remember you. Its signal is not “tech company”, it is “company”, which is why it stays the default. The caveat is supply: ordinary words and short strings were claimed decades ago, so a plain .com for a real English word usually means an aftermarket purchase. Coined and compound names turn up more often than expected, so check rather than assume.
• .io
  Developer tools, infrastructure, technical SaaSAdopted by developer culture because it reads as input and output, and still the most efficient way to signal “built by engineers, for engineers”. The caveat: it is a country-code extension, delegated for the British Indian Ocean Territory, so it sits under a sovereign arrangement you have no part in, and that arrangement is in motion. Details below.
• .ai
  Products where the AI is genuinely the productAnguilla’s country-code extension, which the AI wave turned into the loudest positioning statement available in a domain. Three caveats: pricing runs materially above a commodity extension and renewal is what compounds, it carries the same registry dependency as .io, and the signal is time stamped. It says you were named during the AI boom, current now and dated later.
• .dev
  Developer tools, documentation, engineering-led brandsGoogle Registry, public since 2019, and on the HSTS preload list: browsers refuse to connect over plain HTTP, so HTTPS is enforced before your server is reached and you need a certificate from day one. Developers read that as quiet competence. The caveat is register: to a non-technical buyer, .dev reads as an internal tool rather than a company.
• .app
  Mobile and web applicationsAlso Google Registry, public since 2018, also HSTS preloaded with the same enforced HTTPS. It works best when “the [Name] app” accurately describes what you sell, because the extension finishes that sentence. The caveat is the inverse: if you are a platform, an API, or infrastructure, .app quietly shrinks you to one client.
• .co
  Broad or mixed audiences, technical and notColombia’s country-code extension, opened to registration worldwide in 2010 when the local-presence requirement was lifted, and now used far more outside Colombia than inside it. Short, reads as “company”, and narrows nothing. The caveat is one keystroke: it lives next door to .com, and some people who hear your name will auto-type the .com instead.
• .tech, .cloud
  Redirects, secondaries, campaign sitesThe generic extensions from ICANN’s expansion programme are established and professionally run: .tech under Radix since 2015, .cloud under Aruba since 2014. Stability is not the problem, recognition is. Plenty of people still hesitate at an address they have not seen, and first-year promotional pricing rarely resembles the renewal. Reasonable as a secondary property, a harder case as a company’s only address.

Note that .io, .ai, and .co are country-code extensions: the rules, eligibility, and pricing belong to a registry you have no relationship with.

.io vs .ai vs .dev: choosing between the three tech defaults

These three collect most of the traffic when the .com is gone, and they are not interchangeable. Separate them by who has to be convinced.

Choose .io when your buyer is a developer and the product is infrastructure or tooling: it is the only one of the three that reads as native to that world rather than as a statement about it, so price in the sovereignty footnote below. Choose .ai when artificial intelligence is genuinely the product and you are content to be positioned by your address, accepting that you pay above commodity rates and that the signal has a shelf life. Choose .dev when you want a Google-operated generic extension with no sovereign question attached and enforced HTTPS as a feature. Its limit is reach: precise with engineers, vague with everyone else.

The .io sovereignty question, stated plainly

This deserves accuracy rather than panic or dismissal, and both are common. Here is what is documented. .io is the country-code domain delegated for the British Indian Ocean Territory. In May 2025 the United Kingdom and Mauritius signed a treaty transferring sovereignty of the Chagos Archipelago, the territory in question, but ratification stalled in the UK Parliament and had not completed through the first half of 2026. ICANN has published its position: IO remains an assigned code in ISO 3166-1, the standard a country-code extension’s eligibility depends on. Should a code ever be removed from it, ICANN’s retirement policy, adopted by its board in September 2022, provides a default phase-out of five years, extendable to a maximum of ten. The registry operator continues to sell and renew .io names, with wholesale pricing changes published into 2027.

Here is what is speculation: every specific timeline, whether Mauritius would seek to keep the extension, whether a new code would be issued, and what any of it would mean for existing registrations. Nobody knows, and confident articles claiming otherwise are guessing. The practical read is that this is not a reason to abandon .io, and it is a reason to know which domain you would move to. That is prudent for any country-code extension: you are a tenant in someone else’s namespace, and the landlord writes the rules.

Tech startup domain ideas when the exact .com is gone

Assume you have a name you believe in and its plain .com is registered. That is the ordinary case, not bad luck. Five patterns recover a usable address without touching the word people actually say, roughly from most to least conventional.

• Verb prefixes: get, use, try, joingetacme.com, useacme.com, tryacme.com. The most durable pattern in software, because it reads as English rather than as a workaround and the brand word stays first in speech. Nobody says “get Acme” out loud.
• Suffixes: hq, labs, stack, baseacmehq.com, acmelabs.com. Implies “the official home of” rather than a different company, and does not change how the name sounds. Longer written, but it survives being printed on things.
• Category suffixes for a technical buyeracmeapi.com, acmedata.com. Buys a second signal alongside the name, telling a technical visitor what layer you operate at. The cost is specificity: a category in your domain is one you have to grow out of.
• The domain hackLet the extension finish the word so the whole address reads as one string. A real technique with a specific failure mode rather than a gimmick, and the trade-offs are linked below.
• The plain name on a different extensionSometimes the cleanest answer is the exact name with no scaffolding, on the extension your audience already trusts. Founders skip it because it feels like a compromise, and it is frequently the strongest option here.

Three guardrails separate a pattern that helps from one that quietly costs you. Use one affix, never two stacked. Keep the pure name in your logo, product, and copy, because the affix is scaffolding for a URL and not a rename. And never misspell the name to force availability: dropping a vowel destroys the property the .com was protecting, which is hearing it once and typing it right.

Each pattern opens onto a decision this page deliberately does not make for you. The buy, pivot, or rename fork is worked through in your dream .com is taken. The domain-hack technique, and the country-code risks it bundles, is in domain hacks: are clever URLs worth it. The layered check across domains, trademarks, and social handles is in how to check if a brand name is available.

How Namoly checks a domain, and what it does not check

Domain availability is one of four categories in a Namoly report and carries a weight of 0.30 in the overall score. Inside it, four extensions are weighted: .com at 0.50, .io at 0.20, .app at 0.15, and .co at 0.15. Those weights encode the judgement this guide argues for: the .com is worth half the category, and the tech-flavoured alternatives split the rest.

The lookup is deterministic rather than a guess. It queries RDAP, the structured registration-data protocol registries publish, and falls back to DNS over HTTPS where RDAP is unavailable. Each result comes back as likely available, likely taken, or unknown, and the wording is deliberate: a lookup can tell you a registry holds a record, and only a registrar’s checkout can tell you that you can have it. Unknowns are reported as unknown and pull the confidence signal down.

Two things follow. .ai, .dev, and the generic extensions are not in the weighted set, so choosing one is a brand judgement you layer on top of the score. And Namoly does not check trademarks, social handles, package registries, or app-store names. Treat legal clearance as a separate job and read trademark basics for startup naming before assuming a free domain means a free name.

Frequently asked questions

What is the best domain extension for a tech startup?

The .com remains the default, because it is what people type by reflex and it signals an established company rather than a category. When it is out of reach, match the extension to the audience that already reads it as normal: .io and .dev for developer tools and infrastructure, .app when your product genuinely is an app, .ai when the AI is the product, .co when your audience is mixed. No extension is right for every tech startup, only for a specific buyer.

Is the .io domain going away?

Nothing has changed so far, and the process that would change it is long and public. .io is the country-code extension delegated for the British Indian Ocean Territory. The UK and Mauritius signed a treaty in May 2025 that would transfer sovereignty of the Chagos Archipelago, but ratification stalled in the UK Parliament and had not completed through the first half of 2026. ICANN has stated that IO remains an assigned code in the ISO 3166-1 standard. If a code is ever removed from that standard, ICANN’s retirement policy sets a default phase-out of five years, extendable to a maximum of ten. The registry continues to sell and renew .io names. Beyond those documented facts, any specific timeline is speculation.

Is a .ai domain worth it for a startup?

It depends on whether AI is the product or a feature of it. .ai is Anguilla’s country-code extension, and it delivers positioning no other suffix can match for a genuine AI company. Weigh three things against that: pricing runs higher than a commodity extension and renewal is what compounds, it carries a country-code registry dependency, and it time stamps you as named during the AI wave, which is an asset now and a marker later.

What is the difference between .dev and .app?

Both are operated by Google Registry and both sit on the HSTS preload list, so browsers will only connect to them over HTTPS and you need a certificate from day one. The difference is who they speak to. A .dev address reads as built by and for developers, which suits tools, documentation, and engineering-led brands. A .app address reads as an application, which suits a product where “the [Name] app” is accurate and undersells a platform or an API.

Should I pick the domain first or the name first?

The name first. A domain is a suffix you can change and companies move between them routinely, while a name is what customers repeat and renaming is one of the most expensive things a company can do to itself. Name-first also stops a search box picking your brand: names chosen purely because a string was free tend to be unspellable, unpronounceable, or accidentally meaningful somewhere you sell.