Integration of the site with CRM

Integration of self-writing or #wordprass site with the #CRM system
List of CRM systems with which integration is possible:
#Commo, #AmoCRM, #Pipedrive, #NetHunt, #KeyCRM
If the CRM system is not on the list, then the dop-pay depends on the complexity of the Api.
Additionally, the fee depends on the complexity of the integration.