diff --git a/code/websites/pokedex.online/src/composables/useChallongeClientCredentials.js b/code/websites/pokedex.online/src/composables/useChallongeClientCredentials.js
new file mode 100644
index 0000000..579afe6
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+++ b/code/websites/pokedex.online/src/composables/useChallongeClientCredentials.js
@@ -0,0 +1,275 @@
+/**
+ * Challonge Client Credentials Flow Composable
+ *
+ * Manages client credentials OAuth flow for server-to-server authentication
+ * Used for APPLICATION scope access (application:manage)
+ *
+ * Features:
+ * - Client credentials token exchange
+ * - Automatic token refresh
+ * - Secure credential storage
+ * - Token expiration handling
+ *
+ * Usage:
+ * ```javascript
+ * import { useChallongeClientCredentials } from '@/composables/useChallongeClientCredentials'
+ *
+ * const { 
+ *   isAuthenticated, 
+ *   accessToken, 
+ *   authenticate, 
+ *   logout,
+ *   saveCredentials 
+ * } = useChallongeClientCredentials()
+ *
+ * // Save client credentials (one time)
+ * saveCredentials('your_client_id', 'your_client_secret')
+ *
+ * // Get access token (will auto-refresh if expired)
+ * await authenticate('application:manage tournaments:read tournaments:write')
+ * const token = accessToken.value
+ * ```
+ */
+
+import { ref, computed } from 'vue';
+
+const CREDENTIALS_KEY = 'challonge_client_credentials';
+const TOKEN_KEY = 'challonge_client_token';
+
+// Shared state across all instances
+const credentials = ref(null);
+const tokenData = ref(null);
+const loading = ref(false);
+const error = ref(null);
+
+// Load credentials and token from localStorage on module initialization
+try {
+  const storedCreds = localStorage.getItem(CREDENTIALS_KEY);
+  if (storedCreds) {
+    credentials.value = JSON.parse(storedCreds);
+  }
+
+  const storedToken = localStorage.getItem(TOKEN_KEY);
+  if (storedToken) {
+    tokenData.value = JSON.parse(storedToken);
+
+    // Check if token is expired
+    if (tokenData.value.expires_at && Date.now() >= tokenData.value.expires_at) {
+      console.log('🔄 Client credentials token expired, will need to refresh');
+    }
+  }
+} catch (err) {
+  console.error('Failed to load client credentials:', err);
+}
+
+export function useChallongeClientCredentials() {
+  const isAuthenticated = computed(() => {
+    return !!tokenData.value?.access_token && !isExpired.value;
+  });
+
+  const isExpired = computed(() => {
+    if (!tokenData.value?.expires_at) return true;
+    return Date.now() >= tokenData.value.expires_at;
+  });
+
+  const accessToken = computed(() => {
+    if (isExpired.value) return null;
+    return tokenData.value?.access_token || null;
+  });
+
+  const hasCredentials = computed(() => {
+    return !!(credentials.value?.client_id && credentials.value?.client_secret);
+  });
+
+  const maskedClientId = computed(() => {
+    if (!credentials.value?.client_id) return null;
+    const id = credentials.value.client_id;
+    if (id.length < 12) return id.slice(0, 4) + '••••';
+    return id.slice(0, 6) + '•••••••' + id.slice(-4);
+  });
+
+  /**
+   * Save client credentials to localStorage
+   * @param {string} clientId - OAuth client ID
+   * @param {string} clientSecret - OAuth client secret
+   * @returns {boolean} Success status
+   */
+  function saveCredentials(clientId, clientSecret) {
+    try {
+      if (!clientId || !clientSecret) {
+        throw new Error('Client ID and secret are required');
+      }
+
+      credentials.value = {
+        client_id: clientId,
+        client_secret: clientSecret,
+        saved_at: new Date().toISOString()
+      };
+
+      localStorage.setItem(CREDENTIALS_KEY, JSON.stringify(credentials.value));
+      console.log('✅ Client credentials saved');
+      return true;
+    } catch (err) {
+      error.value = err.message;
+      console.error('Failed to save credentials:', err);
+      return false;
+    }
+  }
+
+  /**
+   * Clear stored credentials and token
+   * @returns {boolean} Success status
+   */
+  function clearCredentials() {
+    try {
+      credentials.value = null;
+      tokenData.value = null;
+      localStorage.removeItem(CREDENTIALS_KEY);
+      localStorage.removeItem(TOKEN_KEY);
+      console.log('✅ Client credentials cleared');
+      return true;
+    } catch (err) {
+      error.value = err.message;
+      console.error('Failed to clear credentials:', err);
+      return false;
+    }
+  }
+
+  /**
+   * Authenticate using client credentials flow
+   * @param {string} scope - Requested scope (e.g., 'application:manage')
+   * @returns {Promise<string>} Access token
+   */
+  async function authenticate(scope = 'application:manage') {
+    if (!hasCredentials.value) {
+      throw new Error(
+        'Client credentials not configured. Use saveCredentials() first.'
+      );
+    }
+
+    // Return existing token if still valid
+    if (isAuthenticated.value && !isExpired.value) {
+      console.log('✅ Using existing valid token');
+      return accessToken.value;
+    }
+
+    loading.value = true;
+    error.value = null;
+
+    try {
+      console.log('🔐 Requesting client credentials token...');
+      console.log('  Client ID:', maskedClientId.value);
+      console.log('  Scope:', scope);
+
+      const response = await fetch('https://api.challonge.com/oauth/token', {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/x-www-form-urlencoded'
+        },
+        body: new URLSearchParams({
+          grant_type: 'client_credentials',
+          client_id: credentials.value.client_id,
+          client_secret: credentials.value.client_secret,
+          scope: scope
+        })
+      });
+
+      if (!response.ok) {
+        const errorData = await response.json();
+        throw new Error(
+          errorData.error_description ||
+            errorData.error ||
+            `Token request failed: ${response.status}`
+        );
+      }
+
+      const data = await response.json();
+
+      // Store token with expiration
+      tokenData.value = {
+        access_token: data.access_token,
+        token_type: data.token_type,
+        scope: data.scope,
+        created_at: Date.now(),
+        expires_in: data.expires_in,
+        expires_at: Date.now() + data.expires_in * 1000
+      };
+
+      // Save to localStorage
+      localStorage.setItem(TOKEN_KEY, JSON.stringify(tokenData.value));
+
+      console.log('✅ Client credentials token obtained');
+      console.log('  Expires in:', data.expires_in, 'seconds');
+      console.log('  Scope:', data.scope);
+
+      return tokenData.value.access_token;
+    } catch (err) {
+      error.value = err.message;
+      console.error('❌ Client credentials authentication failed:', err);
+      throw err;
+    } finally {
+      loading.value = false;
+    }
+  }
+
+  /**
+   * Force token refresh
+   * @param {string} scope - Requested scope
+   * @returns {Promise<string>} New access token
+   */
+  async function refresh(scope = 'application:manage') {
+    // Clear existing token
+    tokenData.value = null;
+    localStorage.removeItem(TOKEN_KEY);
+
+    // Get new token
+    return authenticate(scope);
+  }
+
+  /**
+   * Logout and clear token (keeps credentials)
+   */
+  function logout() {
+    tokenData.value = null;
+    localStorage.removeItem(TOKEN_KEY);
+    console.log('✅ Logged out (credentials retained)');
+  }
+
+  /**
+   * Get token info for debugging
+   */
+  const tokenInfo = computed(() => {
+    if (!tokenData.value) return null;
+
+    const now = Date.now();
+    const expiresAt = tokenData.value.expires_at;
+    const timeUntilExpiry = expiresAt ? expiresAt - now : 0;
+
+    return {
+      hasToken: !!tokenData.value.access_token,
+      isExpired: isExpired.value,
+      scope: tokenData.value.scope,
+      expiresIn: Math.floor(timeUntilExpiry / 1000),
+      expiresAt: expiresAt ? new Date(expiresAt).toLocaleString() : null
+    };
+  });
+
+  return {
+    // State
+    isAuthenticated,
+    isExpired,
+    accessToken,
+    hasCredentials,
+    maskedClientId,
+    loading,
+    error,
+    tokenInfo,
+
+    // Actions
+    saveCredentials,
+    clearCredentials,
+    authenticate,
+    refresh,
+    logout
+  };
+}