get objecttypecode and entityRecordID through web api

Hi, I am trying to make up a record URL through web api. As I know, the URL usually comes in the below format :

"https://" + orgURL + "/main.aspx?etc=" + objectTypeCode +"&id=%7b" + recordId + "%7d&pagetype=entityrecord";

how can I get objecttypecode and recordid through web api, I can use system query?