How to make a 'Captive Portal' on my mobile hotspot? Some Wi-Fi networks such as those you find on coffee shops, when connected to, automatically redirect you to a web page where you will need to do something (enter credentials, accept terms of service, etc) in order to access the internet.
Is the same possible with an android hotspot?
You can't. There are various articles saying its possible, but its not. A captive portal is something kept like the greatest confidential secret, its almost impossible to find how to do it. Especially on Android. Its better to do it through a router.
The technical explanation is long and bad, some may be able to summarize it, yet the biggest problem you will meet is how to do it. People say it's connected to security issues as you are redirecting your users and capturing them. You can also use this to capture their login details and to redirect them to a bank service saying they need to enter their bank card. The information is very well hidden do to these issues and more. That's why no one will tell you, no one will make an app for android for it and only companies use this feature. It's like the method and encryption used on the bank card chips, no one has even heard of it. But in truth it's just a chip with an encryption method.