# Check the name before you buy the domain

> Most name checkers lie about Instagram. A hostname does not. WhatsName takes the name in your head and tells you whether it would even work as a label under castorstack.com.

You already have a name. It showed up in the shower or in a Notion dump, and now you are about to spend an evening checking Instagram, the .com, GitHub, npm, and whatever else still answers. Half of those checks are theater.

Instagram, TikTok, X, Facebook and LinkedIn do not give a straight 404 from a server in a datacenter. They give a login wall, a captcha, or a 200 for a page that does not exist. A tool that paints those green is guessing. I wrote that up and then stopped calling them.

What still answers honestly: GitHub (user and org), the npm registry, and RDAP for `.com`. And before any of that, the boring question that name tools skip: would this even be a legal hostname?

[WhatsName](/whatsname) is that check, pointed at CastorStack. Type a name. It becomes a label. You see `your-name.castorstack` and `your-name.castorstack.com`, whether that label is valid, whether it collides with `app` / `admin` / `api` / `www`, and a guess at the language if you typed a phrase instead of a coined word. Then the plans, because a name is the cheap part.

A green result does not create DNS. It does not mean the trademark is free. It means the string would work as a subdomain if you were going to use one, and that the registries we can actually query did not 200.

If the name is `admin`, it fails. If the name is `Café Novo App`, it becomes `cafe-novo-app`. If you type a single invented token like `acme`, the language line says it could not tell — because it could not.

Use it here: [castorstack.com/whatsname](/whatsname).

## Sources

- [RFC 1035 — domain names](https://www.rfc-editor.org/rfc/rfc1035)
- [GitHub REST API: users](https://docs.github.com/en/rest/users/users)
- [npm registry](https://github.com/npm/registry/blob/main/docs/REGISTRY-API.md)
- [RDAP](https://www.icann.org/rdap)