@edubey, thanks for your quick response. I am not getting complete data using HTTP API. For page http://localhost:4502/api/content/sites/geometrixx/en/toolbar/contacts.json I am getting json containing properties of page but not the exact content showing on the page as contacts. Also, second point seems to be applicable to AEM 6.3 only.
{"links":[{"rel":["self"],"href":"http://localhost:4502/api/content/sites/geometrixx/en/toolbar/contacts.json"},{"rel":["parent"],"href":"http://localhost:4502/api/content/sites/geometrixx/en/toolbar.json"},{"rel":["content"],"href":"http://localhost:4502/content/geometrixx/en/toolbar/contacts.infinity.json"}],"class":["content/page"],"properties":{"dc:title":"Contact","subtitle":"mail","cq:toolbars":["top"],"cq:lastModified":"2010-11-11T23:06:35.180+01:00","name":"contacts","cq:lastModifiedBy":"admin","cq:template":"/apps/geometrixx/templates/contentpage","srn:paging":{"total":0,"offset":0,"limit":20}}}