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) through the public API, and RDAP for a real domain — not a guess painted green.
WhatsName is that check. Type a name. It becomes a label — lowercase, no accents, no spaces. We query RDAP across 12 domains at once (.com, .com.br, .net, .org, .io, .dev, .app, .co, .me, .ai, .tech, .online) and GitHub through the official API. Instagram, TikTok, X, Facebook, LinkedIn and YouTube get a View button that opens the profile for the name you typed — no pretending we can check those automatically. 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 RDAP registries we can actually query did not 200 — that gets you roughly 95% accuracy. A domain can be registered without DNS configured; confirm with the registrar before you buy.
If you type Café Novo App, the label becomes cafe-novo-app — no accents, no spaces, capped at 63 characters, the way domains expect it.
Use it here: castorstack.com/whatsname.