diff --git a/cmd/add_test.go b/cmd/add_test.go
index 293cc1a..6f04142 100644
--- a/cmd/add_test.go
+++ b/cmd/add_test.go
@@ -301,11 +301,11 @@ func TestAddCommandWithAllFlags(t *testing.T) {
 	if receivedBill["payedFor"] != "2,3" { // Alice and Bob
 		t.Errorf("Wrong payedFor: %s", receivedBill["payedFor"])
 	}
-	if receivedBill["categoryid"] != "5" {
-		t.Errorf("Wrong categoryid: %s", receivedBill["categoryid"])
+	if receivedBill["categoryId"] != "5" {
+		t.Errorf("Wrong categoryid: %s", receivedBill["categoryId"])
 	}
-	if receivedBill["paymentmodeid"] != "3" {
-		t.Errorf("Wrong paymentmodeid: %s", receivedBill["paymentmodeid"])
+	if receivedBill["paymentModeId"] != "3" {
+		t.Errorf("Wrong paymentmodeid: %s", receivedBill["paymentModeId"])
 	}
 	if receivedBill["comment"] != "Team dinner" {
 		t.Errorf("Wrong comment: %s", receivedBill["comment"])
diff --git a/internal/api/client.go b/internal/api/client.go
index 566e0d3..eab7827 100644
--- a/internal/api/client.go
+++ b/internal/api/client.go
@@ -359,10 +359,10 @@ func (c *Client) CreateBill(projectID string, bill Bill) error {
 		data.Set("comment", bill.Comment)
 	}
 	if bill.PaymentModeID != 0 {
-		data.Set("paymentmodeid", strconv.Itoa(bill.PaymentModeID))
+		data.Set("paymentModeId", strconv.Itoa(bill.PaymentModeID))
 	}
 	if bill.CategoryID != 0 {
-		data.Set("categoryid", strconv.Itoa(bill.CategoryID))
+		data.Set("categoryId", strconv.Itoa(bill.CategoryID))
 	}
 	if bill.OriginalCurrencyID != 0 {
 		data.Set("original_currency_id", strconv.Itoa(bill.OriginalCurrencyID))
diff --git a/internal/api/client_test.go b/internal/api/client_test.go
index 3d1aa58..49bf31d 100644
--- a/internal/api/client_test.go
+++ b/internal/api/client_test.go
@@ -283,11 +283,11 @@ func TestCreateBill(t *testing.T) {
 				if r.FormValue("comment") != "" {
 					t.Errorf("Comment should be empty: %s", r.FormValue("comment"))
 				}
-				if r.FormValue("paymentmodeid") != "" {
-					t.Errorf("paymentmodeid should be empty: %s", r.FormValue("paymentmodeid"))
+				if r.FormValue("paymentModeId") != "" {
+					t.Errorf("paymentmodeid should be empty: %s", r.FormValue("paymentModeId"))
 				}
-				if r.FormValue("categoryid") != "" {
-					t.Errorf("categoryid should be empty: %s", r.FormValue("categoryid"))
+				if r.FormValue("categoryId") != "" {
+					t.Errorf("categoryid should be empty: %s", r.FormValue("categoryId"))
 				}
 			},
 		},