diff --git a/src/rss_thread_watch/core.clj b/src/rss_thread_watch/core.clj
index fc37fdc..506d8f2 100644
--- a/src/rss_thread_watch/core.clj
+++ b/src/rss_thread_watch/core.clj
@@ -15,6 +15,7 @@
 (ns rss-thread-watch.core
   (:require [clojure.java.io :as io]
             [clojure.edn :as edn]
+            [clojure.string :as s]
             [clojure.tools.cli :refer [parse-opts]]
             [ring.adapter.jetty :as jetty]
             [ring.middleware.params :as rp]
@@ -35,8 +36,8 @@
    :boards-defaults {:refresh-rate 300
                      :starting-page 7
                      :default-chod 94
-                     :target "https://api.4chan.org"
-                     :host "https://boards.4chan.org"
+                     :target "https://api.4chan.org/{board}/catalog.json"
+                     :host "https://boards.4chan.org/{board}/thread/{threadnum}"
                      :lazy-load true}
    :boards-enabled {"/mlp/" {:lazy-load false}
                     "/g/" {:starting-page 7}
@@ -76,17 +77,31 @@
       (with-open [r (io/reader fl)]
         (edn/read (java.io.PushbackReader. r))))))
 
+(defn config-url-expand
+  "Expands substitution in :target and :host fields"
+  [filled-config]
+  (let [boards (get filled-config :boards-enabled)
+        selecting '(:target :host)
+        pattern "{board}"]
+    (u/fmap (fn [board confs]
+              (->> (select-keys confs selecting)
+                   (u/fmap (fn [k v]
+                             (s/replace v pattern (s/replace board "/" ""))))
+                   (merge confs)))
+            boards)))
+
 (defn config-fill-board-defaults
   "Fills every enabled board with default config values"
   [config]
   (let [defaults (:boards-defaults config)]
-    (dissoc (update-in config
-                       '(:boards-enabled)
-                       (fn [mp]
-                         (u/fmap (fn [k v]
-                                   (assoc (u/map-apply-defaults v defaults) :name k))
-                                 mp)))
-            :boards-defaults)))
+    (-> config
+        (update-in '(:boards-enabled)
+                   (fn [mp]
+                     (u/fmap (fn [k v]
+                               (assoc (u/map-apply-defaults v defaults) :name k))
+                             mp)))
+        (dissoc :boards-defaults)
+        (config-url-expand))))
 
 (defn get-some-config
   "Attempts to get config somehow,