Using the REST API with web password

I have activated Restrict the web interface of the Shelly device with "Username" and "Password" on the Shelly.
Now I can't trigger any API actions on that Shelly anymore (I'm using a Shelly i3 to do that).

Is there a way to have both?
Password protection and API calls?

On a browser I can enter the password and than it works again but I haven't seen an option to enter an access password for the Shelly i3 actions.

I'm answering myself.

I just saw in another post that it is possible to prefix the username and password.

http://user:passwort@192.168.xxx.xxx ...