diff --git a/src/lib/app_components/e_app_cfg.svelte b/src/lib/app_components/e_app_cfg.svelte
index a0556dd7..7f5a6661 100644
--- a/src/lib/app_components/e_app_cfg.svelte
+++ b/src/lib/app_components/e_app_cfg.svelte
@@ -3,6 +3,7 @@
 
     import { ae_util } from '$lib/ae_utils/ae_utils';
     import { ae_loc, ae_sess, ae_api, slct, slct_trigger } from '$lib/stores/ae_stores';
+    import E_app_url_builder from '$lib/app_components/e_app_url_builder.svelte';
 
     // import Element_theme from '$lib/e_app_theme.svelte';
 
@@ -230,6 +231,10 @@
             </div>
         </section>
         <!-- END: Utilities -->
+
+        <section class="space-y-2">
+            <E_app_url_builder />
+        </section>
     </div>
 
     <!-- class:justify-between={expand}
diff --git a/src/lib/app_components/e_app_url_builder.svelte b/src/lib/app_components/e_app_url_builder.svelte
new file mode 100644
index 00000000..7a270bc2
--- /dev/null
+++ b/src/lib/app_components/e_app_url_builder.svelte
@@ -0,0 +1,168 @@
+<script lang="ts">
+    /**
+     * e_app_url_builder.svelte
+     * Core URL Param Builder — lets admins construct and copy shareable URLs
+     * with any combination of the core global URL params applied.
+     *
+     * Core params:
+     *   ?iframe=true|false     — hide sys/debug menus (kiosk mode)
+     *   ?theme=<name>          — set theme name on load (stripped from URL after apply)
+     *   ?theme_mode=light|dark — set light/dark mode on load (stripped from URL after apply)
+     *   ?key=<access_key>      — site access key
+     */
+    import { page } from '$app/stores';
+    import { Copy, Check, Link } from '@lucide/svelte';
+
+    // --- Per-param: include this param in the output URL?
+    let use_iframe      = $state(false);
+    let use_theme       = $state(false);
+    let use_theme_mode  = $state(false);
+    let use_key         = $state(false);
+
+    // --- Param values
+    let val_iframe      = $state<'true' | 'false'>('true');
+    let val_theme       = $state('nouveau');
+    let val_theme_mode  = $state<'light' | 'dark'>('dark');
+    let val_key         = $state('');
+
+    // Build the output URL reactively
+    let built_url = $derived.by(() => {
+        const base = $page.url;
+        const u = new URL(base.pathname + base.search + base.hash, base.origin);
+
+        // Remove all core params first so we start clean each time
+        u.searchParams.delete('iframe');
+        u.searchParams.delete('theme');
+        u.searchParams.delete('theme_mode');
+        u.searchParams.delete('key');
+
+        if (use_iframe)     u.searchParams.set('iframe', val_iframe);
+        if (use_theme)      u.searchParams.set('theme', val_theme);
+        if (use_theme_mode) u.searchParams.set('theme_mode', val_theme_mode);
+        if (use_key && val_key.trim()) u.searchParams.set('key', val_key.trim());
+
+        return u.toString();
+    });
+
+    // Output mode: full URL (default) or params-only string
+    let params_only = $state(false);
+
+    let output = $derived.by(() => {
+        if (!params_only) return built_url;
+        const u = new URL(built_url);
+        return u.search || '(no params set)';
+    });
+
+    let copied = $state(false);
+
+    function copy_url() {
+        navigator.clipboard.writeText(output).then(() => {
+            copied = true;
+            setTimeout(() => copied = false, 2000);
+        });
+    }
+
+    const theme_options = [
+        { value: 'cerberus',              label: 'Cerberus' },
+        { value: 'concord',               label: 'Concord' },
+        { value: 'crimson',               label: 'Crimson' },
+        { value: 'hamlindigo',            label: 'Hamlindigo' },
+        { value: 'modern',                label: 'Modern' },
+        { value: 'nouveau',               label: 'Nouveau' },
+        { value: 'rocket',                label: 'Rocket' },
+        { value: 'terminus',              label: 'Terminus' },
+        { value: 'vintage',               label: 'Vintage' },
+        { value: 'wintry',                label: 'Wintry' },
+        { value: 'AE_OSIT_default',       label: 'OSIT' },
+        { value: 'AE_Firefly',            label: 'Firefly ✦' },
+        { value: 'AE_Firefly_SteelBlue',  label: 'Firefly SteelBlue ✦' },
+        { value: 'AE_Firefly_Indigo',     label: 'Firefly Indigo ✦' },
+        { value: 'AE_Firefly_Rainbow',    label: 'Firefly Rainbow ✨' },
+        { value: 'AE_c_IDAA_light',       label: 'IDAA – light' },
+        { value: 'AE_c_LCI',              label: 'LCI' },
+    ];
+</script>
+
+<section class="space-y-3">
+    <h2 class="text-xs font-semibold uppercase tracking-widest text-surface-500 flex items-center gap-1">
+        <Link size="0.9em" /> URL Param Builder
+    </h2>
+
+    <!-- Param toggles -->
+    <div class="space-y-2">
+
+        <!-- iframe -->
+        <div class="flex items-center gap-2">
+            <input id="ubld_iframe" type="checkbox" class="checkbox checkbox-sm" bind:checked={use_iframe} />
+            <label for="ubld_iframe" class="w-20 text-xs font-mono">iframe</label>
+            <select bind:value={val_iframe} disabled={!use_iframe} class="select select-sm text-xs flex-1">
+                <option value="true">true</option>
+                <option value="false">false</option>
+            </select>
+        </div>
+
+        <!-- theme -->
+        <div class="flex items-center gap-2">
+            <input id="ubld_theme" type="checkbox" class="checkbox checkbox-sm" bind:checked={use_theme} />
+            <label for="ubld_theme" class="w-20 text-xs font-mono">theme</label>
+            <select bind:value={val_theme} disabled={!use_theme} class="select select-sm text-xs flex-1">
+                {#each theme_options as opt}
+                    <option value={opt.value}>{opt.label}</option>
+                {/each}
+            </select>
+        </div>
+
+        <!-- theme_mode -->
+        <div class="flex items-center gap-2">
+            <input id="ubld_theme_mode" type="checkbox" class="checkbox checkbox-sm" bind:checked={use_theme_mode} />
+            <label for="ubld_theme_mode" class="w-20 text-xs font-mono">theme_mode</label>
+            <select bind:value={val_theme_mode} disabled={!use_theme_mode} class="select select-sm text-xs flex-1">
+                <option value="light">light</option>
+                <option value="dark">dark</option>
+            </select>
+        </div>
+
+        <!-- key -->
+        <div class="flex items-center gap-2">
+            <input id="ubld_key" type="checkbox" class="checkbox checkbox-sm" bind:checked={use_key} />
+            <label for="ubld_key" class="w-20 text-xs font-mono">key</label>
+            <input
+                type="text"
+                bind:value={val_key}
+                disabled={!use_key}
+                placeholder="access key"
+                class="input input-sm text-xs font-mono flex-1"
+            />
+        </div>
+
+    </div>
+
+    <!-- params_only toggle + output -->
+    <div class="flex items-center gap-2">
+        <input id="ubld_params_only" type="checkbox" class="checkbox checkbox-sm" bind:checked={params_only} />
+        <label for="ubld_params_only" class="text-xs text-surface-500">Params only</label>
+    </div>
+
+    <!-- Output URL -->
+    <div class="flex gap-1 items-stretch">
+        <input
+            type="text"
+            readonly
+            value={output}
+            class="input input-sm text-xs font-mono flex-1 bg-surface-50/50 dark:bg-surface-700/50 cursor-text"
+            onclick={(e) => (e.target as HTMLInputElement).select()}
+            title="Click to select all"
+        />
+        <button
+            class="btn btn-sm {copied ? 'preset-filled-success' : 'preset-tonal-primary'} shrink-0 transition-all"
+            onclick={copy_url}
+            title="Copy URL to clipboard"
+        >
+            {#if copied}
+                <Check size="1em" />
+            {:else}
+                <Copy size="1em" />
+            {/if}
+        </button>
+    </div>
+</section>