availability / platforms and 25 domain extensions
Check username availability everywhere
To check username availability everywhere, enter the name once and UsernameLookup tests it on 300+ public sites and 25 domain extensions in a single run. Each platform comes back free, taken or unknown, with a link to the existing profile when the name is already used.
One name, every place it could live
Naming a product, a channel or a company used to mean twenty browser tabs and a spreadsheet. You would type the handle into Instagram, then TikTok, then X, then YouTube, and still forget Reddit, GitHub and the gaming networks where your audience actually hangs out. By the time you found a free combination, someone had a week to register it first.
An availability check does that work in one pass. We request the public profile address of the name on each platform, read the answer the way a browser would, and sort the results into three states. Taken means a public profile answered. Free means the platform returned its usual "not found" signal. Unknown means the site was slow, blocked the request or changed its page, so we tell you instead of guessing.
The domain side runs in parallel. For each of the 25 extensions we look for DNS records first and ask the registry through RDAP when DNS is silent, which is the same data registrars use. A name that is free on Instagram but taken as a .com is a very different decision from a name that is free on both, and you see both answers side by side.
- Instagram Free
- TikTok Taken
- X Free
- YouTube Free
- Twitch Taken
- acme-studio.com Taken
- acme-studio.io Free
- acme-studio.ai Free
Example of the result layout. Your run checks every platform and extension live.
Username rules on the big platforms
A name can be free and still impossible to register because it breaks a platform's rules. Check the length and the characters before you fall in love with a handle. These are the public limits each platform states for usernames and handles.
| Platform | Length | Allowed characters | Watch out for |
|---|---|---|---|
| up to 30 | letters, digits, periods, underscores | no period at the start or end, no two periods in a row | |
| TikTok | up to 24 | letters, digits, periods, underscores | cannot end with a period |
| X | 4 to 15 | letters, digits, underscores | no periods or hyphens at all |
| YouTube handle | 3 to 30 | letters, digits, periods, underscores, hyphens | handles are separate from the channel name |
| 3 to 20 | letters, digits, underscores, hyphens | names cannot be changed later | |
| GitHub | up to 39 | letters, digits, single hyphens | no hyphen at the start or end |
| Twitch | 4 to 25 | letters, digits, underscores | name changes have a waiting period |
The lowest common denominator is letters, digits and underscores, 4 to 15 characters. A name inside those limits fits everywhere.
A practical way to secure a name before launch
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step 1
Shortlist five names, not one
Your first choice is often taken on at least one network. Bring three to five candidates so a single blocked platform does not stall the whole launch.
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step 2
Run them through one check
Paste the shortlist, include domains, and look at the matrix. A name that is free on the four networks your audience uses beats a prettier name that is free on two.
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step 3
Register the same day
Availability changes. Claim the handles and the domain in one sitting, starting with the platform where the name is hardest to get.
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step 4
Watch for copycats after launch
Once the name is public, lookalike accounts follow. A monitor on the handle flags new accounts with typos or support suffixes before customers find them.
If you are mainly comparing social networks, the social media username checker groups results by network type. When the domain matters as much as the handle, the domain and username checker puts both on one screen. And once the name is live, brand impersonation monitoring keeps watch for lookalikes.
Why some results say unknown
Free checkers often show a confident green tick for every site. That looks tidy and is wrong more often than people think, because many platforms answer a missing profile with a normal page, a login wall or a rate limit. Counting those as free sends you to register a name that is already gone.
We read each site with the signal it actually uses for a missing profile, from an open, community maintained detection dataset. When the answer does not match either the found or the not found pattern, the platform is marked unknown and you can open it with one click to look for yourself.
A public profile answered at the address. You get the link.
The platform returned its own not found signal for that name.
Timeout, block or a changed page. Shown honestly, never guessed.
Availability checks in every plan
Your first search is a one-time demo that shows the first platforms and domains in full. Every paid plan unlocks the full matrix and all 25 extensions. Pro includes 300 availability checks a month, Investigator 2,000 with bulk lists of up to 100 names, and the brand plans go further for teams that name products all year. Plans start at $24 a month billed yearly, see username lookup pricing for the full table.
Questions about checking username availability
How do I check username availability on every platform at once?
Type the name into the search box with "Also check availability" on. UsernameLookup opens the public profile address of that name on each platform, marks it free or taken, and tests 25 domain extensions through DNS and registry lookups in the same run.
Is a name marked free guaranteed to be registrable?
It means no public profile answered at that address when we checked. Some platforms reserve names, block banned accounts or keep deleted handles for a while, so a free result is a strong signal, not a promise. Register the important ones the same day.
Which domain extensions are included?
We check .com, .io, .ai, .co, .app, .net, .org, .dev and 17 more popular extensions such as .me, .gg, .tv, .xyz and .store. Every plan includes all 25 extensions in availability checks.
Can I check several name ideas in one go?
Yes. On the Investigator plan and above you can paste up to 100 names and get a matrix of names against platforms and domains, then export the free combinations as CSV.
Do you register usernames for me?
No. We only check public profile addresses and domain records. Registering a handle stays with you, on each platform, under that platform's own terms.
Check your name everywhere now
One search across 300+ sites and 25 domain extensions. Free, taken or unknown, with links.