Qualify Lead using Web API with Existing Contact

If you want to qualify a lead using WebAPI, the message is Microsoft.Dynamics.CRM.QualifyLead.

https://docs.microsoft.com/en-us/dynamics365/customer-engagement/web-api/qualifylead?view=dynamics-ce-odata-9

If you dont want to create account/contact but in turn link it with existing customer – you can use something like this:

POST https://<org>.crm.dynamics.com/api/data/v9.0/leads(<leadid>)/Microsoft.Dynamics.CRM.QualifyLead

BODY:

{
   "CreateAccount":false,
   "CreateContact":false,
   "CreateOpportunity":true,
   "OpportunityCustomerId":{"@odata.type":"Microsoft.Dynamics.CRM.contact","contactid":"34289935-9A54-EB11-A812-000D3A8B898C"},
   "Status":-1,
   "SuppressDuplicateDetection":true
}

I was however not able to pass both account and contact – so if the lead has already ‘Existing Account’ field filled and you pass the contact in webAPI call, then you will get both account and contact filled in the opportunity record.

function qualifyLeadwithContact(leadId, contactid, clientUrl) {
    try {
        var request = "leads(" + leadId.replace("}", "").replace("{", "") + ")/Microsoft.Dynamics.CRM.QualifyLead";
        var postdata = {
			"CreateAccount":false,
			"CreateContact":false,
			"CreateOpportunity":true,
			"OpportunityCustomerId":{"@odata.type":"Microsoft.Dynamics.CRM.contact","contactid":contactid},
			"Status":-1,
			"SuppressDuplicateDetection":true
				};
        var req = new XMLHttpRequest();
        req.open("POST", clientUrl + "/api/data/v9.0/" + request, true);
        req.setRequestHeader("Accept", "application/json");
        req.setRequestHeader("Content-Type", "application/json; charset=utf-8");
        req.setRequestHeader("OData-MaxVersion", "4.0");
        req.setRequestHeader("OData-Version", "4.0");

        req.onreadystatechange = function () {

            if (this.readyState == 4) {
                req.onreadystatechange = null;

                if (this.status == 200 || this.status == 204) {
                    var result = JSON.parse(this.response);

                } else {
                    var error = JSON.parse(this.response).error;
                }
            }
        };
        req.send(JSON.stringify(postdata));

    } catch (e) {
        throwError(functionName, e);
    }
}