Type a handle once and check it across 30+ platforms. GitHub is verified instantly; the rest open with one click so you can see if it's free.
GitHub is checked automatically. For the others, click to open the profile — if a page loads it's taken, if you get "not found" it's free. (Browsers block silent cross-site checks, so this is the honest, no-account way.)
A consistent username across platforms makes a brand findable and trustworthy. Browsers deliberately block websites from silently checking other sites (CORS), so any tool that claims to auto-check every platform is either using a paid backend or guessing. This one verifies GitHub instantly (its API allows it) and gives you a one-click link to every other platform's profile page — the reliable, private way.