If I have a website and I put up a new page which is not listed in the sitemap and no other page on the website (or anywhere on the web) has a link to it, can a Google bot or any other bot still find and index it? I would like this to be a private webpage that can only be found by inputting the specific URL and not via a search engine.
Yes, it can still be found by robots. It can also still be found by robots even if you ban them via robots.txt, mess around with .htaccess, and so on. The only sane thing to do, to keep a page mostly hidden, is implementing a login-system, or at least only show the information if the request is coming from white-listed sources.
yes they found easily without submitting in index. but if you want keep private your page you can hiding by adding dis allow code in the robot.txt
Thank the feedback. I mostly just don't want to be listed on Google, Yahoo, and Bing search engines so that the page does not show up in search results. Another bot stumbling into it is not a problem. Do the Google/Yahoo/Bing bots do a good job of paying attention to robot.txt?
Yes, Google can find it if you use any third-party Google service that it uses as a tracking vector including Google Analytics, Google Fonts, and any Javascript or other libraries hosted on Google services. If you don't want anybody or any bot to find it, put it in a password protected directory.