diff --git a/app/src/App.svelte b/app/src/App.svelte
index 4a820f4..21f2e7d 100644
--- a/app/src/App.svelte
+++ b/app/src/App.svelte
@@ -12,14 +12,27 @@
               <p class="text-center text-3xl">Configuration</p>
               <p class="text-center">Please provide the scan client token.<br><a target="_blank" class="underline"
                       href="https://docs.lauf-fuer-kaya.de/">See our configuration guide.</a></p>
-              <form class="flex flex-col pt-3 md:pt-8" onsubmit="event.preventDefault();">
+              <form class="flex flex-col pt-3 md:pt-8" onsubmit="event.preventDefault();" on:submit={()=>
+              {
+                  console.log(token);
+              }}>
                   <div class="flex flex-col pt-4">
                       <label for="token" class="text-lg">Client Token</label>
-                      <input type="text" id="token" onchange="tokenchanged()" placeholder="Client Token"
+                      <input type="text" id="token" placeholder="Client Token" bind:value={token}
+                      class:border-red-500={!isTokenValid}
+                      class:border-solid={!isTokenValid}
+                      class:border-3={!isTokenValid}
                           class="shadow appearance-none border rounded w-full py-2 px-3 text-gray-700 mt-1 leading-tight focus:outline-none focus:shadow-outline">
                   </div>
-                  <input id="configure" type="submit" value="Configure"
-                      class="bg-black text-white font-bold text-lg hover:bg-gray-700 p-2 mt-8 cursor-pointer">
+                  {#if !isTokenValid}
+                       <span class="text-sm">Please provide a valid client token...</span>
+                  {/if}
+                  <button
+                  disabled={!isTokenValid}
+            class:cursor-pointer={isTokenValid}
+            class:opacity-50={!isTokenValid}
+                  id="configure" type="submit"
+                      class="bg-black text-white font-bold text-lg hover:bg-gray-700 p-2 mt-8 hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-black">Configure</button>
               </form>
               <div class="text-center pt-12 pb-12">
                   <p><svg style="height: 1rem;display: inline;" xmlns="http://www.w3.org/2000/svg" fill="none"
@@ -34,12 +47,12 @@
           <div class="w-full p-3">
               <div class="inline-block mr-2 mt-2">
                   <button type="button"
-                      class="bg-black focus:outline-none text-white text-sm py-2.5 px-5 rounded-md hover:bg-blue-700">Deutsch
+                      class="bg-black focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-black text-white text-sm py-2.5 px-5 rounded-md hover:bg-blue-700">Deutsch
                       <svg class="h-4 inline" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><path d="M15.923 345.043C52.094 442.527 145.929 512 256 512s203.906-69.473 240.077-166.957L256 322.783l-240.077 22.26z" fill="#ffda44"/><path d="M256 0C145.929 0 52.094 69.472 15.923 166.957L256 189.217l240.077-22.261C459.906 69.472 366.071 0 256 0z"/><path d="M15.923 166.957C5.633 194.69 0 224.686 0 256s5.633 61.31 15.923 89.043h480.155C506.368 317.31 512 287.314 512 256s-5.632-61.31-15.923-89.043H15.923z" fill="#d80027"/></svg></button>
               </div>
               <div class="inline-block mr-2 mt-2">
                   <button type="button"
-                      class="bg-black focus:outline-none text-white text-sm py-2.5 px-5 rounded-md hover:bg-blue-700 bg-blue-700">English
+                      class="bg-black focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-black text-white text-sm py-2.5 px-5 rounded-md hover:bg-blue-700 bg-blue-700">English
                       <svg class="h-4 inline" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512">
                           <circle cx="256" cy="256" r="256" fill="#f0f0f0"></circle>
                           <g fill="#d80027">
@@ -60,4 +73,17 @@
       <div class="w-1/2 shadow-2xl">
           <img alt="" class="object-cover w-full h-screen hidden md:block" src="https://source.unsplash.com/IXUM4cJynP0">
       </div>
-  </div>
\ No newline at end of file
+  </div>
+  <script>
+      let token;
+      $: isTokenValid=token?.length===44&& token.split(".")[0].length===7 &&isUUID(token.split(".")[1]);
+      function isUUID ( uuid ) {
+    let s = "" + uuid;
+
+    s = s.match('^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$');
+    if (s === null) {
+      return false;
+    }
+    return true;
+}
+  </script>
\ No newline at end of file