Subscription to the connected webhook example:

curl --location --request POST '/platform/v1/webhook/subscribe' \
--header 'Authorization: "Bearer API_TOKEN"'\
--header 'Content-Type: application/json' \
--data-raw '{
"event": "payment_gateways_settings/connected",
"target_url": "URL"
}'

Payment gateway connected payload example:

{
	"entity_name": "payment_gateways_settings",
  "event_type": "connected",
  "data": {
  	"business_uid": string,
    "payment_gateway_name": string,
    "is_connected": boolean,
    "is_primary": boolean,
    "updated_at": string
  }
}