htpasswd Generator

Create the user:hash lines of an Apache or Nginx basic auth file

Users
Algorithm
The strongest. Apache 2.4+ and Nginx on current Linux systems (glibc with libxcrypt, musl).
The server pays it on every request. 10 is a good balance, each step doubles the time.
Choose a cost between 4 and 16.
Server configuration
Outside the web root, readable by the server.
Some browsers show it in the login prompt.
Apache (.htaccess or <Directory>)

        
Nginx (server or location block)