Get data from mautic

Development
1

In a single page of a web, how can i get data from mautic? For example to see if the person is a know lead or has visited some page.

Thx

2

In a single page of a web, how can i get data from mautic? For example to see if the person is a know lead or has visited some page.
Thx

3

Thx @kuzmany!, but mautic isn’t in the same domain, is in xxx.mautic.com, so i don´t know who is my lead.

Another question, Is api fast enough for a webpage with many visits?

4

So, how can get the lead id from Mautic hosted on a subdomain? Is there any way? Thanks in advance!