[niftich]

Continuing to honor existing redirects is a relatively simple gesture of goodwill -- it's absolutely what customers expect, it's good for the web, and doesn't need a lot of ongoing effort.

Rather, it looks like they're driving people to a different product intended for a different set of usecases [1]. They want to get out of the generic, commodity web URL shortener business, and drive more of their customers towards more purposeful destination forwarding.

[1] https://firebase.google.com/docs/dynamic-links/use-cases/

[duskwuff]

Crucially, the new product is unlikely to be available through a web interface (at least, without an account), so Google no longer has to deal with their link shortener being used for spam and fraud.

[manquer]

Spammers would not be dettered by the need to use an API. Besides anyone could build a frontend for accessing the API