Unshorten a URL
Paste a shortened link and see exactly where it lands — without visiting it. Works with every shortener, because it follows redirects rather than recognising services.
What you are actually checking
A short link is a promise with the details removed. Sometimes that is convenience — a clean URL in a printed advert, a link that fits in a post. Sometimes it is the point: the destination is hidden because you would not click it if you could see it.
Expanding the link on a server rather than in your browser separates those two cases safely. You get the destination, the full chain that led there, and any warnings worth having — a downgrade to plain HTTP, several shorteners stacked on top of each other, a destination that returns an error.
One caveat worth stating plainly: this tells you where a link goes, not whether the destination is trustworthy. A recognisable domain is not a guarantee.