Force.com Tooling API REST quickstart

RESTToolingAPI.apxc

//Submit an HTTP GET request
public String getHTTP(String svcURL) {
  //HTTP objects
  HttpRequest req = new HttpRequest();
  req.setHeader('Authorization', 'Bearer ' + UserInfo.getSessionID());
  req.setHeader('Content-Type', 'application/json');
        
  String domainUrl = URL.getSalesforceBaseUrl().toExternalForm();
        
  req.setEndpoint(domainUrl + svcURL);
  req.setMethod('GET'); 
                
  Http h = new Http();
  HttpResponse res = h.send(req);
	
  return res.getBody();
}

//Pull layout rows
String response = getHTTP('/services/data/v37.0/tooling/query/?q=SELECT+EntityDefinitionID,LayoutType,ManageableState,Name,NamespacePrefix,TableEnumOrID+FROM+Layout+WHERE+TableEnumOrId=\'Account\'');

System.debug(response);