diff --git a/src/cljs/airsonic_ui/api/helpers.cljs b/src/cljs/airsonic_ui/api/helpers.cljs
index 6959015..8483861 100644
--- a/src/cljs/airsonic_ui/api/helpers.cljs
+++ b/src/cljs/airsonic_ui/api/helpers.cljs
@@ -6,16 +6,29 @@
                      :c "airsonic-ui-cljs"
                      :v "1.15.0"})
 
+(defn- unroll-variadic-params
+  "Turns {:id [1 2 3], :foo :bar} into [[:id 1] [:id 2] [:id 3] [:foo :bar]]"
+  [params]
+  (->>
+   (map (fn [[k vs]]
+          (if (sequential? vs)
+            (map (fn [v] [k v]) vs)
+            [k vs])) params)
+   (flatten)
+   (partition 2)))
+
 (def ^:private encode js/encodeURIComponent)
 
 (defn url
   "Returns an absolute url to an API endpoint"
   [credentials endpoint params]
   (let [server (:server credentials)
-        query (->> (merge default-params (select-keys credentials [:u :p]) params)
+        auth (select-keys credentials [:u :p])
+        query (->> (merge default-params auth params)
+                   (unroll-variadic-params)
                    (map (fn [[k v]] (str (encode (name k)) "=" (encode v))))
                    (str/join "&"))]
-    (str server (when-not (str/ends-with? server "/") "/") "rest/" endpoint "?" query)))
+    (str (str/replace server #"/+$" "") "/rest/" endpoint "?" query)))
 
 (defn stream-url [credentials song-or-episode]
   ;; podcasts have a stream-id, normal songs just use their id
@@ -63,4 +76,3 @@
              #{:artistId :name :songCount :artist} :album
              #{:id :name :albumCount} :artist
              :unknown)))
-
diff --git a/test/cljs/airsonic_ui/api/helpers_test.cljs b/test/cljs/airsonic_ui/api/helpers_test.cljs
index 3c50ab3..53ea60f 100644
--- a/test/cljs/airsonic_ui/api/helpers_test.cljs
+++ b/test/cljs/airsonic_ui/api/helpers_test.cljs
@@ -26,6 +26,17 @@
           encoded-str (js/encodeURIComponent query)]
       (is (str/includes? (api/url {:server "http://localhost"} "search3" {:query query}) encoded-str)))))
 
+(deftest variadic-parameters
+  (testing "Should append list-like parameters correctly"
+    (is (= (count (re-seq #"id=" (api/url {:server "http://localost"} "test" {:id []}))) 0))
+    (is (= (count (re-seq #"id=" (api/url {:server "http://localost"} "test" {:id [1]}))) 1))
+    (is (= (count (re-seq #"id=" (api/url {:server "http://localost"} "test" {:id (range 10)}))) 10)))
+  (testing "Should keep the non-lists"
+    (let [mixed (api/url {:server "http://localost"} "test" {:id (range 5) :foo "bar"})]
+      (is (some? (re-find #"u=user" (api/url {:server "http://localhost"} "test" {:u "user"}))))
+      (is (and (some? (re-find #"foo=bar" mixed))
+               (= (count (re-seq #"id=" mixed)) 5))))))
+
 (deftest stream-urls
   (testing "Should construct the url based on a song's id"
     (let [stream-url (api/stream-url {:server "http://localhost"} fixtures/song)]