(I understand you can make a workaround like getting all pages from a space and check if one of them has the input URL and then you can find the page ID, etc… but it is really not the preferred way to do it.)
So, is there any way to get page data (such as pageID) by URL?
If not, is there a specific reason for that?
If it’s something like https://domain.atlassian.net/wiki/spaces/SPACE/pages/pageID/title
then you can just extract the page id from the url and use it to call the get pages endpoint like normal.
If you were not aware, the Confluence Cloud and Confluence Server/DC products have been diverging for many years. It’s best to keep questions separate for these concerns because the answers will usually be different. In your original post, you referred to the Confluence Cloud documentation but now you’re mentioning Server/DC. Would you prefer an answer about Server/DC? In which case, I can move the post to that category.