How to get Custom field id in Salesforce?

Hi Tanu,

To get custom field Id in Salesforce you have to use Tooling Api. Here is a piece of code , Hopefully it will help you.

HttpRequest req = new HttpRequest();
req.setHeader('Authorization', 'Bearer ' + UserInfo.getSessionID());
req.setHeader('Content-Type', 'application/json');

String toolingendpoint = 'https://na1.salesforce.com/services/data/v20.0/tooling/';

//query for custom fields
endpoint += 'query/?q=select+id,DeveloperName,FullName+from+CustomField+limit+1'
req.setEndpoint(endpoint);
req.setMethod('GET')

Http h = new Http();
HttpResponse res = h.send(req);
system.debug(res.getBody());

Thanks