diff --git a/app/Http/Controllers/Admin/AuthController.php b/app/Http/Controllers/Admin/AuthController.php
index ce3230ac..f1ff1752 100644
--- a/app/Http/Controllers/Admin/AuthController.php
+++ b/app/Http/Controllers/Admin/AuthController.php
@@ -81,9 +81,10 @@ public function handleGoogleCallback(Request $request)
         Auth::login($user, remember: true);
         $request->session()->regenerate();
 
-        $defaultUrl = $user->username
-            ? route('user.profile', $user->username)
-            : route('profile.edit');
+        $needsOnboarding = empty($user->username) || $user->username === "student_{$user->id}" || empty($user->institution);
+        $defaultUrl = $needsOnboarding
+            ? route('onboarding.index')
+            : route('user.profile', $user->username);
 
         $redirect = redirect()->intended($defaultUrl);
 
diff --git a/app/Http/Controllers/OnboardingController.php b/app/Http/Controllers/OnboardingController.php
new file mode 100644
index 00000000..2c3a9db4
--- /dev/null
+++ b/app/Http/Controllers/OnboardingController.php
@@ -0,0 +1,129 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Models\User;
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Http\Request;
+use Illuminate\Support\Str;
+use Illuminate\Validation\Rule;
+use Inertia\Inertia;
+use Inertia\Response;
+
+class OnboardingController extends Controller
+{
+    /**
+     * Show the onboarding screen.
+     */
+    public function show(Request $request): Response|RedirectResponse
+    {
+        $user = $request->user();
+
+        // If user already customized their username and set institution, skip onboarding
+        if (! empty($user->username) && $user->username !== "student_{$user->id}" && ! empty($user->institution)) {
+            return redirect()->intended(route('user.profile', ['username' => $user->username]));
+        }
+
+        // Generate a clean suggested username from name or email
+        $suggestedUsername = $this->generateSuggestedUsername($user);
+
+        return Inertia::render('Onboarding', [
+            'user' => [
+                'name' => $user->name,
+                'email' => $user->email,
+                'suggested_username' => $suggestedUsername,
+                'institution' => $user->institution ?? '',
+            ],
+        ]);
+    }
+
+    /**
+     * Complete onboarding and store profile details.
+     */
+    public function store(Request $request): RedirectResponse
+    {
+        $user = $request->user();
+
+        $validated = $request->validate([
+            'name' => ['required', 'string', 'max:255'],
+            'username' => [
+                'required',
+                'string',
+                'min:3',
+                'max:30',
+                'regex:/^[a-zA-Z0-9_]+$/',
+                Rule::unique('users', 'username')->ignore($user->id),
+            ],
+            'institution' => ['required', 'string', 'max:255'],
+        ], [
+            'username.regex' => 'The username may only contain letters, numbers, and underscores.',
+            'username.unique' => 'This username is already taken. Please choose another one.',
+        ]);
+
+        $user->update([
+            'name' => $validated['name'],
+            'username' => Str::lower($validated['username']),
+            'institution' => $validated['institution'],
+        ]);
+
+        return redirect()->intended(route('user.profile', ['username' => $user->username]))
+            ->with('success', 'Welcome to HSCStack! Your profile is ready.');
+    }
+
+    /**
+     * Real-time username availability checker API.
+     */
+    public function checkUsername(Request $request)
+    {
+        $username = trim((string) $request->query('username', ''));
+
+        if (empty($username) || strlen($username) < 3 || strlen($username) > 30 || ! preg_match('/^[a-zA-Z0-9_]+$/', $username)) {
+            return response()->json([
+                'valid' => false,
+                'available' => false,
+                'message' => 'Username must be 3-30 characters (letters, numbers, underscores).',
+            ]);
+        }
+
+        $userId = $request->user()?->id;
+        $isTaken = User::where('username', Str::lower($username))
+            ->when($userId, fn ($query) => $query->where('id', '!=', $userId))
+            ->exists();
+
+        return response()->json([
+            'valid' => true,
+            'available' => ! $isTaken,
+            'message' => $isTaken ? 'This username is already taken.' : 'Username is available!',
+        ]);
+    }
+
+    /**
+     * Helper to generate a unique suggested username.
+     */
+    private function generateSuggestedUsername(User $user): string
+    {
+        $base = Str::slug($user->name, '_');
+        $base = preg_replace('/[^a-zA-Z0-9_]/', '', $base);
+
+        if (empty($base) || strlen($base) < 3) {
+            $base = Str::before($user->email, '@');
+            $base = preg_replace('/[^a-zA-Z0-9_]/', '', $base);
+        }
+
+        $base = Str::lower(substr($base, 0, 20));
+
+        if (strlen($base) < 3) {
+            $base = 'student';
+        }
+
+        $suggested = $base;
+        $counter = 1;
+
+        while (User::where('username', $suggested)->where('id', '!=', $user->id)->exists()) {
+            $suggested = "{$base}_{$counter}";
+            $counter++;
+        }
+
+        return $suggested;
+    }
+}
diff --git a/resources/js/pages/Onboarding.vue b/resources/js/pages/Onboarding.vue
new file mode 100644
index 00000000..d6d1ab8f
--- /dev/null
+++ b/resources/js/pages/Onboarding.vue
@@ -0,0 +1,415 @@
+<script setup lang="ts">
+import { Head, useForm } from '@inertiajs/vue3';
+import {
+    Sparkles,
+    User as UserIcon,
+    AtSign,
+    ArrowRight,
+    Loader2,
+    CheckCircle2,
+    XCircle,
+    Building2,
+} from 'lucide-vue-next';
+import { ref, watch } from 'vue';
+import AppLogo from '@/components/AppLogo.vue';
+
+const props = defineProps<{
+    user: {
+        name: string;
+        email: string;
+        suggested_username: string;
+        institution: string;
+    };
+}>();
+
+const form = useForm({
+    name: props.user?.name || '',
+    username: props.user?.suggested_username || '',
+    institution: props.user?.institution || '',
+});
+
+// Live username availability state
+const isCheckingUsername = ref(false);
+const usernameStatus = ref<{
+    checked: boolean;
+    available: boolean;
+    message: string;
+}>({
+    checked: false,
+    available: false,
+    message: '',
+});
+
+let debounceTimer: ReturnType<typeof setTimeout> | null = null;
+
+const checkAvailability = (val: string) => {
+    const cleanVal = val.trim().toLowerCase().replace(/\s+/g, '_');
+    form.username = cleanVal;
+
+    if (!cleanVal || cleanVal.length < 3) {
+        usernameStatus.value = {
+            checked: false,
+            available: false,
+            message: '',
+        };
+
+        return;
+    }
+
+    if (!/^[a-zA-Z0-9_]+$/.test(cleanVal)) {
+        usernameStatus.value = {
+            checked: true,
+            available: false,
+            message: 'Only letters, numbers, and underscores are allowed.',
+        };
+
+        return;
+    }
+
+    if (debounceTimer) {
+        clearTimeout(debounceTimer);
+    }
+
+    isCheckingUsername.value = true;
+
+    debounceTimer = setTimeout(async () => {
+        try {
+            const res = await fetch(
+                `/api/check-username?username=${encodeURIComponent(cleanVal)}`,
+                {
+                    headers: { Accept: 'application/json' },
+                },
+            );
+
+            if (res.ok) {
+                const data = await res.json();
+                usernameStatus.value = {
+                    checked: true,
+                    available: data.available,
+                    message: data.message,
+                };
+            }
+        } catch {
+            // Ignore background error
+        } finally {
+            isCheckingUsername.value = false;
+        }
+    }, 350);
+};
+
+watch(
+    () => form.username,
+    (newVal) => {
+        checkAvailability(newVal);
+    },
+    { immediate: true },
+);
+
+// Quick suggestions for college / institution
+const quickInstitutions = [
+    'Notre Dame College',
+    'Dhaka College',
+    'Rajuk Uttara Model College',
+    'Adamjee Cantonment College',
+    'Viqarunnisa Noon College',
+    'Holy Cross College',
+    'Chittagong College',
+];
+
+const selectInstitution = (name: string) => {
+    form.institution = name;
+};
+
+const submit = () => {
+    form.post('/onboarding', {
+        preserveScroll: true,
+    });
+};
+</script>
+
+<template>
+    <Head>
+        <title>Welcome to HSCStack - Complete Your Profile</title>
+        <meta
+            name="description"
+            content="Complete your profile to join the HSCStack community."
+        />
+    </Head>
+
+    <div
+        class="relative flex min-h-screen flex-col justify-between bg-slate-50 px-4 py-8 font-sans antialiased sm:px-6 lg:px-8 dark:bg-zinc-950"
+    >
+        <!-- Background Ambient Glow -->
+        <div class="pointer-events-none fixed inset-0 z-0 overflow-hidden">
+            <div
+                class="absolute -top-[20%] left-1/2 h-[700px] w-[1000px] -translate-x-1/2 rounded-full bg-[radial-gradient(ellipse_at_center,rgba(99,102,241,0.15)_0%,rgba(165,180,252,0.03)_50%,transparent_70%)] blur-[100px] dark:bg-[radial-gradient(ellipse_at_center,rgba(99,102,241,0.08)_0%,transparent_70%)]"
+            ></div>
+        </div>
+
+        <!-- Top Minimal Nav -->
+        <header class="relative z-10 mx-auto w-full max-w-xl">
+            <div class="flex items-center justify-between">
+                <AppLogo />
+                <span
+                    class="inline-flex items-center gap-1.5 rounded-full border border-indigo-200/80 bg-indigo-50/80 px-3 py-1 text-xs font-semibold text-indigo-700 shadow-2xs dark:border-indigo-900/60 dark:bg-indigo-950/60 dark:text-indigo-300"
+                >
+                    <Sparkles class="h-3.5 w-3.5" />
+                    Quick Profile Setup
+                </span>
+            </div>
+        </header>
+
+        <!-- Main Form Card -->
+        <main class="relative z-10 my-auto py-8">
+            <div
+                class="mx-auto w-full max-w-xl overflow-hidden rounded-3xl border border-slate-200/80 bg-white p-6 shadow-xl shadow-slate-200/40 sm:p-10 dark:border-zinc-800 dark:bg-zinc-900 dark:shadow-none"
+            >
+                <!-- Title Header -->
+                <div class="mb-8">
+                    <h1
+                        class="text-2xl font-black tracking-tight text-slate-900 sm:text-3xl dark:text-zinc-100"
+                    >
+                        Welcome to HSCStack 👋
+                    </h1>
+                    <p
+                        class="mt-2 text-sm leading-relaxed text-slate-500 dark:text-zinc-400"
+                    >
+                        Let's set up your profile so you can join discussions,
+                        ask questions in Global Chat, and share resources.
+                    </p>
+                </div>
+
+                <form @submit.prevent="submit" class="space-y-6">
+                    <!-- 1. Full Name -->
+                    <div>
+                        <label
+                            for="name"
+                            class="mb-1.5 flex items-center justify-between text-xs font-bold tracking-wider text-slate-700 uppercase dark:text-zinc-300"
+                        >
+                            <span>Full Name</span>
+                            <span
+                                class="text-[11px] font-normal text-slate-400 dark:text-zinc-500"
+                            >
+                                Display Name
+                            </span>
+                        </label>
+                        <div class="relative">
+                            <div
+                                class="pointer-events-none absolute inset-y-0 left-0 flex items-center pl-3.5 text-slate-400 dark:text-zinc-500"
+                            >
+                                <UserIcon class="h-4 w-4" />
+                            </div>
+                            <input
+                                id="name"
+                                v-model="form.name"
+                                type="text"
+                                required
+                                placeholder="Your full name"
+                                :disabled="form.processing"
+                                class="w-full rounded-xl border border-slate-200 bg-slate-50/50 py-2.5 pr-4 pl-10 text-sm font-medium text-slate-900 transition outline-none focus:border-indigo-500 focus:bg-white focus:ring-4 focus:ring-indigo-500/10 disabled:opacity-60 dark:border-zinc-700 dark:bg-zinc-800/50 dark:text-zinc-100 dark:focus:border-indigo-400 dark:focus:bg-zinc-800"
+                                :class="
+                                    form.errors.name ? 'border-rose-500!' : ''
+                                "
+                            />
+                        </div>
+                        <p
+                            v-if="form.errors.name"
+                            class="mt-1 text-xs text-rose-600 dark:text-rose-400"
+                        >
+                            {{ form.errors.name }}
+                        </p>
+                    </div>
+
+                    <!-- 2. Username / Handle -->
+                    <div>
+                        <div class="mb-1.5 flex items-center justify-between">
+                            <label
+                                for="username"
+                                class="text-xs font-bold tracking-wider text-slate-700 uppercase dark:text-zinc-300"
+                            >
+                                Username
+                            </label>
+
+                            <!-- Live Availability Indicator -->
+                            <div
+                                class="flex items-center gap-1 text-xs font-medium"
+                            >
+                                <span
+                                    v-if="isCheckingUsername"
+                                    class="flex items-center gap-1 text-slate-400 dark:text-zinc-500"
+                                >
+                                    <Loader2
+                                        class="h-3 w-3 animate-spin text-indigo-500"
+                                    />
+                                    Checking...
+                                </span>
+                                <span
+                                    v-else-if="
+                                        usernameStatus.checked &&
+                                        usernameStatus.available
+                                    "
+                                    class="flex items-center gap-1 text-emerald-600 dark:text-emerald-400"
+                                >
+                                    <CheckCircle2 class="h-3.5 w-3.5" />
+                                    Available
+                                </span>
+                                <span
+                                    v-else-if="
+                                        usernameStatus.checked &&
+                                        !usernameStatus.available
+                                    "
+                                    class="flex items-center gap-1 text-rose-600 dark:text-rose-400"
+                                >
+                                    <XCircle class="h-3.5 w-3.5" />
+                                    {{ usernameStatus.message }}
+                                </span>
+                            </div>
+                        </div>
+
+                        <div class="relative">
+                            <div
+                                class="pointer-events-none absolute inset-y-0 left-0 flex items-center pl-3.5 text-slate-400 dark:text-zinc-500"
+                            >
+                                <AtSign class="h-4 w-4" />
+                            </div>
+                            <input
+                                id="username"
+                                v-model="form.username"
+                                type="text"
+                                required
+                                minlength="3"
+                                maxlength="30"
+                                placeholder="your_handle"
+                                :disabled="form.processing"
+                                class="w-full rounded-xl border border-slate-200 bg-slate-50/50 py-2.5 pr-4 pl-10 font-mono text-sm text-slate-900 transition outline-none focus:border-indigo-500 focus:bg-white focus:ring-4 focus:ring-indigo-500/10 disabled:opacity-60 dark:border-zinc-700 dark:bg-zinc-800/50 dark:text-zinc-100 dark:focus:border-indigo-400 dark:focus:bg-zinc-800"
+                                :class="
+                                    form.errors.username ||
+                                    (usernameStatus.checked &&
+                                        !usernameStatus.available)
+                                        ? 'border-rose-500!'
+                                        : ''
+                                "
+                            />
+                        </div>
+
+                        <!-- Live Link Preview -->
+                        <div class="mt-1.5 flex items-center justify-between">
+                            <p
+                                class="text-[11px] text-slate-400 dark:text-zinc-500"
+                            >
+                                Public Profile:
+                                <span
+                                    class="font-mono text-indigo-600 dark:text-indigo-400"
+                                >
+                                    hscstack.com/u/{{
+                                        form.username || 'username'
+                                    }}
+                                </span>
+                            </p>
+                        </div>
+                        <p
+                            v-if="form.errors.username"
+                            class="mt-1 text-xs text-rose-600 dark:text-rose-400"
+                        >
+                            {{ form.errors.username }}
+                        </p>
+                    </div>
+
+                    <!-- 3. College / School Name -->
+                    <div>
+                        <label
+                            for="institution"
+                            class="mb-1.5 flex items-center justify-between text-xs font-bold tracking-wider text-slate-700 uppercase dark:text-zinc-300"
+                        >
+                            <span>College / School</span>
+                            <span
+                                class="text-[11px] font-normal text-slate-400 dark:text-zinc-500"
+                            >
+                                Institution
+                            </span>
+                        </label>
+                        <div class="relative">
+                            <div
+                                class="pointer-events-none absolute inset-y-0 left-0 flex items-center pl-3.5 text-slate-400 dark:text-zinc-500"
+                            >
+                                <Building2 class="h-4 w-4" />
+                            </div>
+                            <input
+                                id="institution"
+                                v-model="form.institution"
+                                type="text"
+                                required
+                                placeholder="e.g. Notre Dame College"
+                                :disabled="form.processing"
+                                class="w-full rounded-xl border border-slate-200 bg-slate-50/50 py-2.5 pr-4 pl-10 text-sm font-medium text-slate-900 transition outline-none focus:border-indigo-500 focus:bg-white focus:ring-4 focus:ring-indigo-500/10 disabled:opacity-60 dark:border-zinc-700 dark:bg-zinc-800/50 dark:text-zinc-100 dark:focus:border-indigo-400 dark:focus:bg-zinc-800"
+                                :class="
+                                    form.errors.institution
+                                        ? 'border-rose-500!'
+                                        : ''
+                                "
+                            />
+                        </div>
+
+                        <!-- Quick Choice Chips -->
+                        <div class="mt-2.5 flex flex-wrap items-center gap-1.5">
+                            <span
+                                class="text-[10px] font-semibold text-slate-400 dark:text-zinc-500"
+                            >
+                                Popular:
+                            </span>
+                            <button
+                                v-for="inst in quickInstitutions"
+                                :key="inst"
+                                type="button"
+                                @click="selectInstitution(inst)"
+                                class="cursor-pointer rounded-lg border border-slate-200/80 bg-slate-100/70 px-2 py-0.5 text-[11px] font-medium text-slate-600 transition hover:border-indigo-300 hover:bg-indigo-50 hover:text-indigo-700 active:scale-95 dark:border-zinc-700/80 dark:bg-zinc-800 dark:text-zinc-400 dark:hover:border-indigo-500/50 dark:hover:bg-indigo-950/40 dark:hover:text-indigo-300"
+                            >
+                                {{ inst }}
+                            </button>
+                        </div>
+                        <p
+                            v-if="form.errors.institution"
+                            class="mt-1 text-xs text-rose-600 dark:text-rose-400"
+                        >
+                            {{ form.errors.institution }}
+                        </p>
+                    </div>
+
+                    <!-- Submit Button -->
+                    <div class="pt-2">
+                        <button
+                            type="submit"
+                            :disabled="
+                                form.processing ||
+                                isCheckingUsername ||
+                                (usernameStatus.checked &&
+                                    !usernameStatus.available)
+                            "
+                            class="flex w-full cursor-pointer items-center justify-center gap-2 rounded-xl bg-indigo-600 py-3 text-sm font-bold text-white shadow-md shadow-indigo-600/20 transition-all hover:bg-indigo-700 hover:shadow-lg hover:shadow-indigo-600/30 active:scale-[0.99] disabled:cursor-not-allowed disabled:opacity-50"
+                        >
+                            <Loader2
+                                v-if="form.processing"
+                                class="h-4 w-4 animate-spin"
+                            />
+                            <template v-else>
+                                <span>Complete Setup & Enter</span>
+                                <ArrowRight class="h-4 w-4" />
+                            </template>
+                        </button>
+                    </div>
+                </form>
+            </div>
+        </main>
+
+        <!-- Footer -->
+        <footer class="relative z-10 mx-auto text-center">
+            <p class="text-xs text-slate-400 dark:text-zinc-500">
+                Logged in as
+                <span class="font-medium text-slate-600 dark:text-zinc-300">{{
+                    user.email
+                }}</span>
+                • You can edit additional profile details later in Settings.
+            </p>
+        </footer>
+    </div>
+</template>
diff --git a/routes/web.php b/routes/web.php
index 3d29b952..5749ba62 100644
--- a/routes/web.php
+++ b/routes/web.php
@@ -5,6 +5,7 @@
 use App\Http\Controllers\BlogController;
 use App\Http\Controllers\ChatController;
 use App\Http\Controllers\NodeController;
+use App\Http\Controllers\OnboardingController;
 use App\Http\Controllers\ProfileController;
 use App\Http\Controllers\ResourceController;
 use App\Http\Controllers\ShortUrlController;
@@ -21,6 +22,10 @@
 });
 
 Route::middleware(['throttle:60,1', 'auth'])->group(function () {
+    Route::get('/onboarding', [OnboardingController::class, 'show'])->name('onboarding.index');
+    Route::post('/onboarding', [OnboardingController::class, 'store'])->name('onboarding.store');
+    Route::get('/api/check-username', [OnboardingController::class, 'checkUsername'])->name('onboarding.check-username');
+
     Route::get('/profile', [ProfileController::class, 'edit'])->name('profile.edit');
     Route::put('/profile', [ProfileController::class, 'update'])->name('profile.update');
     Route::post('/api/short-urls', [ShortUrlController::class, 'store'])->name('short-urls.store');
diff --git a/tests/Feature/AuthenticationTest.php b/tests/Feature/AuthenticationTest.php
index 374ccc04..439a5f7d 100644
--- a/tests/Feature/AuthenticationTest.php
+++ b/tests/Feature/AuthenticationTest.php
@@ -28,7 +28,7 @@
     $response = $this->get(route('auth.google.callback'));
 
     $user = User::where('email', 'newuser@example.com')->first();
-    $response->assertRedirect(route('user.profile', $user->username));
+    $response->assertRedirect(route('onboarding.index'));
     $response->assertSessionHas('success', 'Account not found. New account created.');
     $this->assertAuthenticated();
     $this->assertDatabaseHas('users', [
diff --git a/tests/Feature/OnboardingTest.php b/tests/Feature/OnboardingTest.php
new file mode 100644
index 00000000..576a19dc
--- /dev/null
+++ b/tests/Feature/OnboardingTest.php
@@ -0,0 +1,142 @@
+<?php
+
+use App\Models\User;
+
+test('guest is redirected to login when accessing onboarding', function () {
+    $response = $this->get(route('onboarding.index'));
+
+    $response->assertRedirect(route('login'));
+});
+
+test('new user can view onboarding page with suggested username', function () {
+    $user = User::factory()->create([
+        'name' => 'Tajim Ahmed',
+        'username' => 'student_999',
+        'institution' => null,
+    ]);
+
+    $response = $this->actingAs($user)->get(route('onboarding.index'));
+
+    $response->assertOk();
+    $response->assertInertia(fn ($page) => $page
+        ->component('Onboarding')
+        ->has('user.suggested_username')
+        ->where('user.name', 'Tajim Ahmed')
+    );
+});
+
+test('already onboarded user is redirected to profile when accessing onboarding', function () {
+    $user = User::factory()->create([
+        'username' => 'tajim_pro',
+        'institution' => 'Notre Dame College',
+    ]);
+
+    $response = $this->actingAs($user)->get(route('onboarding.index'));
+
+    $response->assertRedirect(route('user.profile', ['username' => 'tajim_pro']));
+});
+
+test('user can complete onboarding and is redirected to profile', function () {
+    $user = User::factory()->create([
+        'name' => 'Original Name',
+        'username' => 'student_123',
+        'institution' => null,
+    ]);
+
+    $response = $this->actingAs($user)->post(route('onboarding.store'), [
+        'name' => 'Tajim Ahmed',
+        'username' => 'tajim_ahmed',
+        'institution' => 'Notre Dame College',
+    ]);
+
+    $response->assertRedirect(route('user.profile', ['username' => 'tajim_ahmed']));
+
+    $user->refresh();
+    expect($user->name)->toBe('Tajim Ahmed');
+    expect($user->username)->toBe('tajim_ahmed');
+    expect($user->institution)->toBe('Notre Dame College');
+});
+
+test('onboarding validates unique username', function () {
+    User::factory()->create([
+        'username' => 'existing_handle',
+    ]);
+
+    $user = User::factory()->create([
+        'username' => 'student_456',
+        'institution' => null,
+    ]);
+
+    $response = $this->actingAs($user)->post(route('onboarding.store'), [
+        'name' => 'Tajim Ahmed',
+        'username' => 'existing_handle',
+        'institution' => 'Notre Dame College',
+    ]);
+
+    $response->assertSessionHasErrors(['username']);
+});
+
+test('onboarding validates required fields', function () {
+    $user = User::factory()->create([
+        'username' => 'student_789',
+        'institution' => null,
+    ]);
+
+    $response = $this->actingAs($user)->post(route('onboarding.store'), [
+        'name' => '',
+        'username' => '',
+        'institution' => '',
+    ]);
+
+    $response->assertSessionHasErrors(['name', 'username', 'institution']);
+});
+
+test('check username endpoint returns availability status', function () {
+    User::factory()->create([
+        'username' => 'taken_user',
+    ]);
+
+    $user = User::factory()->create();
+
+    // Check taken username
+    $response = $this->actingAs($user)->getJson('/api/check-username?username=taken_user');
+    $response->assertOk()
+        ->assertJson([
+            'valid' => true,
+            'available' => false,
+        ]);
+
+    // Check available username
+    $response = $this->actingAs($user)->getJson('/api/check-username?username=fresh_user_123');
+    $response->assertOk()
+        ->assertJson([
+            'valid' => true,
+            'available' => true,
+        ]);
+
+    // Check invalid format
+    $response = $this->actingAs($user)->getJson('/api/check-username?username=ab');
+    $response->assertOk()
+        ->assertJson([
+            'valid' => false,
+            'available' => false,
+        ]);
+});
+
+test('onboarding respects intended redirect url', function () {
+    $user = User::factory()->create([
+        'username' => 'student_555',
+        'institution' => null,
+    ]);
+
+    // Set intended URL in session
+    session()->put('url.intended', '/chat');
+
+    $response = $this->actingAs($user)->post(route('onboarding.store'), [
+        'name' => 'Tajim Ahmed',
+        'username' => 'tajim_chat',
+        'institution' => 'Notre Dame College',
+    ]);
+
+    $response->assertRedirect('/chat');
+});