[strogonoff]

AnkiWeb[0], made by or at least affiliated with Anki creator, allows accessing and studying any of the decks you sync in your Anki app.

It also features a database of user-contributed decks[1] on various topics.

That said, I don’t know whether AnkiWeb could be used completely without the accompanying desktop or mobile app.

[0] https://ankiweb.net/

[1] https://ankiweb.net/shared/decks/

[dorchadas]

You can, and I've done it some since migrating to iOS until I feel like I'll use it enough to pay for the app (I suck at sticking with flashcards; they're so boring).