Shared by the original developer : GitHub - foXaCe/ajax-security-hass: Home Assistant integration for Ajax Security Systems
(source : Alarme Ajax sur Home assistant - #144 par foXaCe - Intégration - Home Assistant Communauté Francophone)
If you have already an API Key: it will work out of the box
Otherwise if you do not have an API Key: you need to wait the availability of an Ajax proxy server
The dev foXaCe, Ajax and most probably other hidden people (not me) are working hard