How to send location with webhook

Hello, this should be simple, but I cannot get it working. I have debugged nexttracks to get HTTP POST, but when I replicate it in other app it does not work.

Can someone please describe how to set up web hook so it acts as device tracker? I send following, but it does not work. Sending may not be problem, but I do not know how to set reception webhook in Home Assistant.

POST /api/webhook/caef4006433a679ec---some generated ID-------a4ef3b547e593b55e7db 
HTTP/1.1 
User-Agent: Nexttracks/32100 
Authorization: Basic some_code
X-Limit-U: <HA username>
X-Limit-D: <mobile device name>
Cache-Control: no-cache 
Content-Type: application/json; charset=utf-8 
Content-Length: 186 
Host: IP_address:8123 
Connection: Keep-Alive 
Accept-Encoding: gzip 
 
{"_type":"location","acc":13,"alt":333,"batt":54,"conn":"w","inregions":["HomeX","HomeX_extended"],"lat":<latitude>,"lon":<longitude>,"tid":"01","tst":<timestamp>,"vac":5,"vel":2}