var parameters = { TemplateId: "07B94C1D-C85F-492F-B120-F0A743C540E6",//Guid of template Regarding: { contactid: "CA26BD09-62B4-E711-A94F-000D3A109280",//entity that will be used for templating "@odata.type": "Microsoft.Dynamics.CRM.contact" }, Target: {//stub of email that has to contain at least one valid recipient "@odata.type": "Microsoft.Dynamics.CRM.email", email_activity_parties: [{ "partyid_contact@odata.bind": "/contacts(CA26BD09-62B4-E711-A94F-000D3A109280)", participationtypemask: 2//To }] } }; var context; if (typeof GetGlobalContext === "function") { context = GetGlobalContext(); } else { context = Xrm.Page.context; } var req = new XMLHttpRequest(); req.open("POST", context.getClientUrl() + "/api/data/v8.2/SendEmailFromTemplate", true); req.setRequestHeader("OData-MaxVersion", "4.0"); req.setRequestHeader("OData-Version", "4.0"); req.setRequestHeader("Accept", "application/json"); req.setRequestHeader("Content-Type", "application/json; charset=utf-8"); req.onreadystatechange = function () { if (this.readyState === 4) { req.onreadystatechange = null; if (this.status === 200) { //Success - No Return Data - Do Something } else { var errorText = this.responseText; //Error and errorText variable contains an error - do something with it } } }; req.send(JSON.stringify(parameters));