diff --git a/kfet/static/kfet/js/kfet.api.js b/kfet/static/kfet/js/kfet.api.js
index 2418195d..bfadc4dd 100644
--- a/kfet/static/kfet/js/kfet.api.js
+++ b/kfet/static/kfet/js/kfet.api.js
@@ -185,24 +185,14 @@ class APIModelObject extends ModelObject {
      * Get data of a distant model instance. It sends a GET HTTP request to
      * {@link Models.APIModelObject#url_read}.
      * @param   {object} [api_options] Additional data appended to the request.
-     * @param   {jQueryAjaxSuccess} [on_success] A function to be called if the request succeeds.
-     * @param   {jQueryAjaxError} [on_error] A function to be called if the request fails.
      */
-    fromAPI(api_options, on_success, on_error) {
-        var that = this;
-
+    fromAPI(api_options) {
         api_options = api_options || {};
-        on_success = on_success || $.noop;
-        on_error = on_error || $.noop;
 
         api_options['format'] = 'json';
 
-        $.getJSON(this.url_read, api_options)
-            .done(function (json, textStatus, jqXHR) {
-                that.from(json);
-                on_success(json, textStatus, jqXHR);
-            })
-            .fail(on_error);
+        return $.getJSON(this.url_read, api_options)
+            .done( (json) => this.from(json) );
     }
 
     /**
@@ -213,9 +203,9 @@ class APIModelObject extends ModelObject {
      * @param   {jQueryAjaxError} [on_error]
      * @see {@link Models.APIModelObject#fromAPI|fromAPI}
      */
-    get_by_apipk(api_pk, api_options, on_success, on_error) {
+    get_by_apipk(api_pk, api_options) {
         this.url_read = this.constructor.url_read_for(api_pk);
-        this.fromAPI(api_options, on_success, on_error);
+        return this.fromAPI(api_options);
     }
 
     /**
diff --git a/kfet/static/kfet/js/kpsul.js b/kfet/static/kfet/js/kpsul.js
index 1917c53e..f9aa8e23 100644
--- a/kfet/static/kfet/js/kpsul.js
+++ b/kfet/static/kfet/js/kpsul.js
@@ -84,10 +84,9 @@ class AccountManager {
         trigramme = trigramme || this.selection.get();
 
         if (trigramme.isValidTri()) {
-            this.account.get_by_apipk(trigramme, {},
-                    () => this._update_on_success(),
-                    () => this.reset_data()
-            );
+            this.account.get_by_apipk(trigramme)
+                .done( () => this._update_on_success() )
+                .fail( () => this.reset_data() );
         } else {
             this.reset_data();
         }
@@ -279,9 +278,9 @@ class CheckoutManager {
             'last_statement': true,
         };
 
-        this.checkout.get_by_apipk(id, api_options,
-                (data) => this._update_on_success(data),
-                () => this.reset_data());
+        this.checkout.get_by_apipk(id, api_options)
+            .done( (data) => this._update_on_success(data) )
+            .fail( () => this.reset_data() );
 
         if (kpsul.account_manager.is_empty()) {
             kpsul.account_manager.focus();