How We Choose, Test and Re-Check the Sites We Search

A detection rule is the test that tells a real profile page apart from a "user not found" page on one site. A username search is only as good as its site list. A broken rule either says a profile exists when it doesn't, or misses one that does. This page explains how we build and maintain the list behind the FreeUsername username search, so you can judge how far to trust a result.

Our own engine

Every check runs on the FreeUsername™ engine, which we designed and built ourselves. It has its own site list and its own detection rules. In version 0.0.2 we removed all third-party site lists and detection data from the website. The list currently covers 3,450+ sites, and you can browse all of them on the supported sites page.

How a site gets added

We add a site when its public profiles live at a predictable address, such as a page that includes the username in the URL. Each site is tagged with a category, like social, video, coding or gaming, and a tier: major platforms, niche sites and smaller forums. The tier sets the order results stream in, so the best-known sites show up first.

How each rule is tested

1. We write a detection rule for the site: what an existing profile looks like and what a missing one looks like.
2. We test the rule against a real, known account. It must come back Found.
3. We test it against a made-up name nobody would register. It must come back Not found.
4. If either test fails, the site doesn't go live until the rule is fixed.

Say the site is a small forum and the handle is nightowl92. We write a rule for its profile page, run it on a real member's name (it must say Found), then run it on a nonsense name like a random string of letters (it must say Not found). Only then does the forum show up in your results for nightowl92.

When a site changes its pages, we update the rule. We don't copy site lists or detection rules from other projects.

Nightly checks

Every site is re-checked each night, because sites change without warning. A site that fails is hidden automatically until it works again. That keeps broken rules out of your results, at the cost of a site sometimes disappearing for a few days.

The four statuses

Each result gets one of four statuses, and only two of them are real answers.

Status	What it means	Is the name free?
Found	The site returned what looks like an existing public profile.	No, it looks taken
Not found	The response matched the pattern for a missing profile.	Probably, check on the site
Blocked	The site refused or rate-limited the request, so there is no answer.	Unknown
Unknown	The response didn't clearly match either pattern, for example after a timeout.	Unknown

Tools that only show "available" or "taken" hide the Blocked and Unknown cases, which can make a name look free when it isn't. For Found results we also show the public display name, avatar and bio when the site makes them available, so you can check the profile yourself.

What can still go wrong

Wrong results still happen. A rule can lag behind a site redesign between nightly checks, so false positives and missed profiles still happen. A Found result means a profile with that name exists, not who owns it. If you spot a wrong result, use the report link on that result. The how it works page and our editorial policy cover the rest.

What we don't keep

We don't keep the usernames you search. The username you type is sent to our server only to run the check. It is not stored or logged, and there is no sign-up.

FAQ

Why did a site disappear from my results?

Most likely it failed a nightly check and was hidden until its rule works again.

Can I suggest a site?

Yes. Send it through the contact page. We add it only after it passes the tests above.

Is this related to the WhatsMyName project?

No. FreeUsername is not affiliated with or endorsed by the WhatsMyName project. Our search runs on our own engine.

A note on responsible use

Results are leads to verify, not facts about a person. FreeUsername is not a consumer reporting agency, and its results must not be used for decisions about employment, credit, housing or insurance.