Is python a substitute to php in backend development

Answer 1

Depends ...
If you prefer python as backend go with django..
Else if you prefer php then I will suggest Laravel☺

Answer 2

Yes python can be used on its own to make websites. A good example is the website realpython.com. It is made entirely in python and looks and responds very nicely. Python is better used in conjunction with other languages to fully exploit it. Many big websites such as Netflix use python. But both languages have their pros and cons. Php for example, is very fast, but can be a headache to create and maintain. you can look at the comparison here: https://www.quora.com/Which-is-better-PHP-or-Python-Why