To check IMEI you need to send GET request to this endpoint with IMEI in url path and API_KEY in query params. Your list of available tokens you can find in your account dashboard. After successful request you will receive response with request details including ID of request. If request will not be rejected balance will be reduced by the price of the request. For more information about service(include service ID) see the list of available services in /service/services/ endpoint. Use /api-sync/ instead of /api/ if You want to create one-step request for service.