From 53914eac50e3e97db37cde289293fa4e60cd4b22 Mon Sep 17 00:00:00 2001
From: Dennis Petersmann <dennis@petersmann.dev>
Date: Tue, 20 Oct 2026 12:38:21 +0200
Subject: [PATCH] feat: show local time on profiles, opt-in

Adds a show_local_time setting next to the timezone. When on and a timezone is set, the profile shows the current time there with its UTC offset, like GitHub does. It is off by default and clearing the timezone turns it off.
---
 KNOWLEDGE_BASE.md                             |  4 +-
 app/Actions/CreateExport.php                  |  1 +
 app/Actions/UpdateUserTimezone.php            |  7 ++-
 .../Controllers/UserTimezoneController.php    |  2 +-
 .../Requests/UpdateUserTimezoneRequest.php    |  6 +++
 app/Models/User.php                           |  3 ++
 ...000_add_show_local_time_to_users_table.php | 17 +++++++
 resources/js/components/local-time.tsx        | 44 +++++++++++++++++
 resources/js/components/timezone-picker.tsx   | 48 +++++++++++++++++--
 resources/js/lib/utils.ts                     | 18 +++++++
 resources/js/pages/user/show.tsx              |  4 ++
 resources/js/types/auth.ts                    |  1 +
 .../Controllers/ExportControllerTest.php      |  2 +
 .../Controllers/UserControllerTest.php        | 15 ++++++
 .../UserTimezoneControllerTest.php            | 46 ++++++++++++++++++
 tests/Unit/Actions/UpdateUserTimezoneTest.php | 26 ++++++++++
 tests/Unit/AuthorHover.test.tsx               |  1 +
 tests/Unit/CommitThread.test.tsx              |  1 +
 tests/Unit/FollowState.test.tsx               |  1 +
 tests/Unit/GuestFollow.test.tsx               |  1 +
 tests/Unit/Models/UserTest.php                |  1 +
 tests/Unit/NotificationInbox.test.tsx         |  1 +
 tests/Unit/UtcOffset.test.ts                  | 25 ++++++++++
 23 files changed, 267 insertions(+), 8 deletions(-)
 create mode 100644 database/migrations/2026_10_20_120000_add_show_local_time_to_users_table.php
 create mode 100644 resources/js/components/local-time.tsx
 create mode 100644 tests/Unit/UtcOffset.test.ts

diff --git a/KNOWLEDGE_BASE.md b/KNOWLEDGE_BASE.md
index ba3e3c840..24482f93e 100644
--- a/KNOWLEDGE_BASE.md
+++ b/KNOWLEDGE_BASE.md
@@ -353,9 +353,9 @@ Settings → Appearance offers:
 
 These appearance choices are saved in the browser, not on the account, so each browser keeps its own. Settings → Profile lets you choose one of six lane colors (Orange, Green, Violet, Teal, Rose, Ochre), a custom color, or the automatic color used around your identity and activity graph.
 
-Profile settings also let you share a timezone. Timestamps can show the author's local time as well as the viewer's when a timezone is shared. Leaving it unset uses the browser's timezone for your display without publishing your timezone. These /dev/null preferences are separate from your GitHub-managed profile information.
+Profile settings also let you share a timezone. Timestamps can show the author's local time as well as the viewer's when a timezone is shared. Leaving it unset uses the browser's timezone for your display without publishing your timezone. A separate, off-by-default setting shows your current local time on your profile, next to your location and website; it only applies while a timezone is set, and clearing the timezone turns it off. These /dev/null preferences are separate from your GitHub-managed profile information.
 
-Sources: [appearance settings](resources/js/pages/appearance/update.tsx), [lane picker](resources/js/components/lane-picker.tsx), [timezone picker](resources/js/components/timezone-picker.tsx), [timestamp tooltip](resources/js/components/timestamp-tooltip.tsx).
+Sources: [appearance settings](resources/js/pages/appearance/update.tsx), [lane picker](resources/js/components/lane-picker.tsx), [timezone picker](resources/js/components/timezone-picker.tsx), [local time](resources/js/components/local-time.tsx), [timestamp tooltip](resources/js/components/timestamp-tooltip.tsx).
 
 ### Installing /dev/null as an app
 
diff --git a/app/Actions/CreateExport.php b/app/Actions/CreateExport.php
index 2ae21603c..5b4f57520 100644
--- a/app/Actions/CreateExport.php
+++ b/app/Actions/CreateExport.php
@@ -50,6 +50,7 @@ public function handle(User $user): array
                 'has_sponsors_listing' => $user->has_sponsors_listing,
                 'preferred_lane' => $user->preferred_lane,
                 'timezone' => $user->timezone,
+                'show_local_time' => $user->show_local_time,
                 'translation_language' => $user->translation_language,
                 'lane_color' => $user->lane_color,
                 'pasteis_mode' => $user->pasteis_mode,
diff --git a/app/Actions/UpdateUserTimezone.php b/app/Actions/UpdateUserTimezone.php
index 167eaa6f8..c66be990c 100644
--- a/app/Actions/UpdateUserTimezone.php
+++ b/app/Actions/UpdateUserTimezone.php
@@ -8,8 +8,11 @@
 
 final readonly class UpdateUserTimezone
 {
-    public function handle(User $user, ?string $timezone): void
+    public function handle(User $user, ?string $timezone, bool $showLocalTime = false): void
     {
-        $user->update(['timezone' => $timezone]);
+        $user->update([
+            'timezone' => $timezone,
+            'show_local_time' => $timezone !== null && $showLocalTime,
+        ]);
     }
 }
diff --git a/app/Http/Controllers/UserTimezoneController.php b/app/Http/Controllers/UserTimezoneController.php
index c62e58109..5edfe7c61 100644
--- a/app/Http/Controllers/UserTimezoneController.php
+++ b/app/Http/Controllers/UserTimezoneController.php
@@ -15,7 +15,7 @@
 {
     public function update(UpdateUserTimezoneRequest $request, #[CurrentUser] User $user, UpdateUserTimezone $action): RedirectResponse
     {
-        $action->handle($user, $request->timezone());
+        $action->handle($user, $request->timezone(), $request->showLocalTime());
 
         Inertia::flash('toast', [
             'type' => 'success',
diff --git a/app/Http/Requests/UpdateUserTimezoneRequest.php b/app/Http/Requests/UpdateUserTimezoneRequest.php
index 9f4de87a5..a626e9020 100644
--- a/app/Http/Requests/UpdateUserTimezoneRequest.php
+++ b/app/Http/Requests/UpdateUserTimezoneRequest.php
@@ -20,6 +20,7 @@ public function rules(): array
     {
         return [
             'timezone' => ['present', 'nullable', 'string', 'timezone:all'],
+            'show_local_time' => ['nullable', 'boolean'],
         ];
     }
 
@@ -27,4 +28,9 @@ public function timezone(): ?string
     {
         return $this->filled('timezone') ? $this->string('timezone')->value() : null;
     }
+
+    public function showLocalTime(): bool
+    {
+        return $this->boolean('show_local_time');
+    }
 }
diff --git a/app/Models/User.php b/app/Models/User.php
index a66f3680e..ee06d6c94 100644
--- a/app/Models/User.php
+++ b/app/Models/User.php
@@ -46,6 +46,7 @@
  * @property-read string|null $pinned_commit_id
  * @property-read string|null $translation_language
  * @property-read string|null $timezone
+ * @property-read bool $show_local_time
  * @property-read LivePlatform|null $live_platform
  * @property-read string|null $live_url
  * @property-read CarbonInterface|null $live_ends_at
@@ -122,6 +123,7 @@ final class User extends Authenticatable
     protected $attributes = [
         'log' => Log::Following->value,
         'translation_language' => null,
+        'show_local_time' => false,
         'pasteis_mode' => false,
         'remotes_enabled' => true,
         'remotes_from' => RemotesFrom::Following->value,
@@ -171,6 +173,7 @@ public function casts(): array
             'pasteis_given_on' => 'date',
             'pinned_commit_id' => 'string',
             'timezone' => 'string',
+            'show_local_time' => 'boolean',
             'translation_language' => 'encrypted',
             'log' => Log::class,
             'onboarded_at' => 'datetime',
diff --git a/database/migrations/2026_10_20_120000_add_show_local_time_to_users_table.php b/database/migrations/2026_10_20_120000_add_show_local_time_to_users_table.php
new file mode 100644
index 000000000..a282b83b5
--- /dev/null
+++ b/database/migrations/2026_10_20_120000_add_show_local_time_to_users_table.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::table('users', function (Blueprint $table): void {
+            $table->boolean('show_local_time')->default(false);
+        });
+    }
+};
diff --git a/resources/js/components/local-time.tsx b/resources/js/components/local-time.tsx
new file mode 100644
index 000000000..3cece5c3a
--- /dev/null
+++ b/resources/js/components/local-time.tsx
@@ -0,0 +1,44 @@
+import { Clock } from 'lucide-react';
+import { useSyncExternalStore } from 'react';
+import { formatUtcOffset, formatZonedTime } from '@/lib/utils';
+
+const MINUTE = 60_000;
+
+function subscribe(onChange: () => void): () => void {
+    const interval = setInterval(onChange, MINUTE);
+
+    return () => clearInterval(interval);
+}
+
+/**
+ * Snapshots are whole minutes, so the clock re-renders when the minute turns rather than on every read.
+ */
+function currentMinute(): number {
+    return Math.floor(Date.now() / MINUTE) * MINUTE;
+}
+
+/**
+ * What time it is for someone who chose to share their timezone. It renders nothing on the server, where the
+ * current time is not the reader's.
+ */
+export function LocalTime({ timeZone }: { timeZone: string }) {
+    const minute = useSyncExternalStore(subscribe, currentMinute, () => null);
+
+    if (minute === null) {
+        return null;
+    }
+
+    const now = new Date(minute);
+
+    return (
+        <li className="flex items-center gap-1.5" data-test="local-time">
+            <Clock className="size-4" />
+            <span>
+                <time dateTime={now.toISOString()}>
+                    {formatZonedTime(now.toISOString(), timeZone)}
+                </time>{' '}
+                ({formatUtcOffset(now, timeZone)})
+            </span>
+        </li>
+    );
+}
diff --git a/resources/js/components/timezone-picker.tsx b/resources/js/components/timezone-picker.tsx
index b403de480..5a91e147c 100644
--- a/resources/js/components/timezone-picker.tsx
+++ b/resources/js/components/timezone-picker.tsx
@@ -14,6 +14,8 @@ import UserTimezoneController from '@/actions/App/Http/Controllers/UserTimezoneC
 import Heading from '@/components/heading';
 import InputError from '@/components/input-error';
 import { Button } from '@/components/ui/button';
+import { Checkbox } from '@/components/ui/checkbox';
+import { Label } from '@/components/ui/label';
 import { useUser } from '@/hooks/use-user';
 import { browserTimeZone } from '@/lib/utils';
 
@@ -49,6 +51,7 @@ function matches(timeZone: TimeZone, query: string): boolean {
 export default function TimezonePicker() {
     const { user } = useUser();
     const [selected, setSelected] = useState<string | null>(user.timezone);
+    const [showLocalTime, setShowLocalTime] = useState(user.show_local_time);
     const [query, setQuery] = useState('');
     const detected = useSyncExternalStore(
         subscribe,
@@ -68,7 +71,7 @@ export default function TimezonePicker() {
         <section className="px-4 py-6 sm:px-6">
             <Heading
                 title="Timezone"
-                description="Hover a commit or reply time to see it in your timezone, and in the author's when they have set one. Others see yours the same way. Leave it unset to use your browser's timezone without sharing it."
+                description="Hover a commit or reply time to see it in your timezone, and in the author's when they have set one. Others see yours the same way. Leave it unset to use your browser's timezone without sharing it. Your local time only shows on your profile if you turn that on below."
             />
 
             <Form
@@ -83,6 +86,14 @@ export default function TimezonePicker() {
                             value={selected ?? ''}
                         />
 
+                        <input
+                            type="hidden"
+                            name="show_local_time"
+                            value={
+                                selected !== null && showLocalTime ? '1' : '0'
+                            }
+                        />
+
                         <Combobox
                             value={selected}
                             onChange={(value: string | null) =>
@@ -169,7 +180,10 @@ export default function TimezonePicker() {
                             {selected !== null && (
                                 <button
                                     type="button"
-                                    onClick={() => setSelected(null)}
+                                    onClick={() => {
+                                        setSelected(null);
+                                        setShowLocalTime(false);
+                                    }}
                                     className="text-muted-foreground underline-offset-4 hover:text-foreground hover:underline"
                                 >
                                     Unset
@@ -177,10 +191,38 @@ export default function TimezonePicker() {
                             )}
                         </div>
 
+                        <div className="mt-4 flex items-start gap-2">
+                            <Checkbox
+                                id="show-local-time"
+                                checked={selected !== null && showLocalTime}
+                                disabled={selected === null}
+                                onCheckedChange={(checked) =>
+                                    setShowLocalTime(checked === true)
+                                }
+                                className="mt-0.5"
+                                data-test="show-local-time-checkbox"
+                            />
+                            <Label
+                                htmlFor="show-local-time"
+                                className="block text-sm leading-snug font-normal"
+                            >
+                                Show my local time on my profile
+                                <span className="block text-muted-foreground">
+                                    Anyone who opens your profile sees the
+                                    current time in your timezone.
+                                </span>
+                            </Label>
+                        </div>
+
                         <Button
                             type="submit"
                             className="mt-5"
-                            disabled={processing || selected === user.timezone}
+                            disabled={
+                                processing ||
+                                (selected === user.timezone &&
+                                    (selected === null ||
+                                        showLocalTime === user.show_local_time))
+                            }
                             data-test="save-timezone-button"
                         >
                             Save timezone
diff --git a/resources/js/lib/utils.ts b/resources/js/lib/utils.ts
index 4be9efbca..ea2545a01 100644
--- a/resources/js/lib/utils.ts
+++ b/resources/js/lib/utils.ts
@@ -219,6 +219,24 @@ export function formatZonedTime(date: string, timeZone: string): string {
     });
 }
 
+/**
+ * The offset a timezone has at a moment, like `UTC +02:00`, or `UTC` when it has none.
+ */
+export function formatUtcOffset(date: Date, timeZone: string): string {
+    const offset = new Intl.DateTimeFormat('en-US', {
+        timeZone,
+        timeZoneName: 'longOffset',
+    })
+        .formatToParts(date)
+        .find((part) => part.type === 'timeZoneName')?.value;
+
+    if (offset === undefined || offset === 'GMT' || offset === 'GMT+00:00') {
+        return 'UTC';
+    }
+
+    return offset.replace('GMT', 'UTC ');
+}
+
 export function formatZonedDate(date: string, timeZone: string): string {
     const value = new Date(date);
 
diff --git a/resources/js/pages/user/show.tsx b/resources/js/pages/user/show.tsx
index 20a3500ee..d91b20327 100644
--- a/resources/js/pages/user/show.tsx
+++ b/resources/js/pages/user/show.tsx
@@ -26,6 +26,7 @@ import {
     LiveAvatarMarker,
     LiveStreamTrigger,
 } from '@/components/live-stream-card';
+import { LocalTime } from '@/components/local-time';
 import { PageTabs } from '@/components/page-tabs';
 import { PinCommitButton } from '@/components/pin-commit-button';
 import { ProfileActionsMenu } from '@/components/profile-actions-menu';
@@ -266,6 +267,9 @@ export default function Show({
                             {user.location}
                         </li>
                     )}
+                    {user.show_local_time && user.timezone && (
+                        <LocalTime timeZone={user.timezone} />
+                    )}
                     {user.website && (
                         <li className="flex min-w-0 items-center gap-1.5">
                             <Link2 className="size-4 shrink-0" />
diff --git a/resources/js/types/auth.ts b/resources/js/types/auth.ts
index 43a68a065..9b664c5d2 100644
--- a/resources/js/types/auth.ts
+++ b/resources/js/types/auth.ts
@@ -24,6 +24,7 @@ export type User = {
     has_github_account: boolean;
     lane: Lane;
     timezone: string | null;
+    show_local_time: boolean;
     /**
      * Only set while the user is streaming.
      */
diff --git a/tests/Feature/Controllers/ExportControllerTest.php b/tests/Feature/Controllers/ExportControllerTest.php
index fddf625c7..1cc29e343 100644
--- a/tests/Feature/Controllers/ExportControllerTest.php
+++ b/tests/Feature/Controllers/ExportControllerTest.php
@@ -54,6 +54,7 @@
         'has_sponsors_listing' => true,
         'preferred_lane' => 3,
         'timezone' => 'Europe/Budapest',
+        'show_local_time' => true,
         'translation_language' => 'ja',
         'lane_color' => '#1a2b3c',
         'pasteis_mode' => true,
@@ -93,6 +94,7 @@
             'has_sponsors_listing' => true,
             'preferred_lane' => 3,
             'timezone' => 'Europe/Budapest',
+            'show_local_time' => true,
             'translation_language' => 'ja',
             'lane_color' => '#1a2b3c',
             'pasteis_mode' => true,
diff --git a/tests/Feature/Controllers/UserControllerTest.php b/tests/Feature/Controllers/UserControllerTest.php
index f670c4488..402a5e70c 100644
--- a/tests/Feature/Controllers/UserControllerTest.php
+++ b/tests/Feature/Controllers/UserControllerTest.php
@@ -48,6 +48,21 @@
             ->where('commits.data.1.body', 'Older'));
 });
 
+it('only lets guests see the local time of users who opted in', function (): void {
+    User::factory()->create(['username' => 'shared', 'timezone' => 'Europe/Berlin', 'show_local_time' => true]);
+    User::factory()->create(['username' => 'private', 'timezone' => 'Europe/Berlin']);
+
+    $this->get('/@shared')
+        ->assertInertia(fn (AssertableInertia $page): AssertableInertia => $page
+            ->where('user.timezone', 'Europe/Berlin')
+            ->where('user.show_local_time', true));
+
+    $this->get('/@private')
+        ->assertInertia(fn (AssertableInertia $page): AssertableInertia => $page
+            ->where('user.timezone', 'Europe/Berlin')
+            ->where('user.show_local_time', false));
+});
+
 it('renders whether the user can be sponsored on github', function (): void {
     $user = User::factory()->create(['has_sponsors_listing' => true]);
 
diff --git a/tests/Feature/Controllers/UserTimezoneControllerTest.php b/tests/Feature/Controllers/UserTimezoneControllerTest.php
index 14df01a32..8e8cccbdd 100644
--- a/tests/Feature/Controllers/UserTimezoneControllerTest.php
+++ b/tests/Feature/Controllers/UserTimezoneControllerTest.php
@@ -20,6 +20,52 @@
     expect($user->refresh()->timezone)->toBe('Europe/Budapest');
 });
 
+it('may opt in to showing the local time', function (): void {
+    $user = User::factory()->create();
+
+    $this->actingAs($user)
+        ->fromRoute('user-profile.edit')
+        ->put(route('user-timezone.update'), ['timezone' => 'Europe/Budapest', 'show_local_time' => true])
+        ->assertRedirectToRoute('user-profile.edit');
+
+    expect($user->refresh())
+        ->timezone->toBe('Europe/Budapest')
+        ->show_local_time->toBeTrue();
+});
+
+it('may opt out of showing the local time', function (): void {
+    $user = User::factory()->create(['timezone' => 'Europe/Budapest', 'show_local_time' => true]);
+
+    $this->actingAs($user)
+        ->fromRoute('user-profile.edit')
+        ->put(route('user-timezone.update'), ['timezone' => 'Europe/Budapest', 'show_local_time' => false]);
+
+    expect($user->refresh()->show_local_time)->toBeFalse();
+});
+
+it('never shows the local time without a timezone', function (): void {
+    $user = User::factory()->create(['timezone' => 'Europe/Budapest', 'show_local_time' => true]);
+
+    $this->actingAs($user)
+        ->fromRoute('user-profile.edit')
+        ->put(route('user-timezone.update'), ['timezone' => null, 'show_local_time' => true]);
+
+    expect($user->refresh())
+        ->timezone->toBeNull()
+        ->show_local_time->toBeFalse();
+});
+
+it('rejects a show_local_time that is not a boolean', function (): void {
+    $user = User::factory()->create();
+
+    $this->actingAs($user)
+        ->fromRoute('user-profile.edit')
+        ->put(route('user-timezone.update'), ['timezone' => 'Europe/Budapest', 'show_local_time' => 'maybe'])
+        ->assertSessionHasErrors('show_local_time');
+
+    expect($user->refresh()->timezone)->toBeNull();
+});
+
 it('may clear the timezone', function (mixed $timezone): void {
     $user = User::factory()->create(['timezone' => 'Europe/Budapest']);
 
diff --git a/tests/Unit/Actions/UpdateUserTimezoneTest.php b/tests/Unit/Actions/UpdateUserTimezoneTest.php
index 58f947b91..deba2c063 100644
--- a/tests/Unit/Actions/UpdateUserTimezoneTest.php
+++ b/tests/Unit/Actions/UpdateUserTimezoneTest.php
@@ -24,3 +24,29 @@
 
     expect($user->refresh()->timezone)->toBeNull();
 });
+
+it('may show the local time on the profile', function (): void {
+    $user = User::factory()->create();
+
+    resolve(UpdateUserTimezone::class)->handle($user, 'America/New_York', true);
+
+    expect($user->refresh()->show_local_time)->toBeTrue();
+});
+
+it('does not show the local time by default', function (): void {
+    $user = User::factory()->create();
+
+    resolve(UpdateUserTimezone::class)->handle($user, 'America/New_York');
+
+    expect($user->refresh()->show_local_time)->toBeFalse();
+});
+
+it('stops showing the local time once the timezone is cleared', function (): void {
+    $user = User::factory()->create(['timezone' => 'America/New_York', 'show_local_time' => true]);
+
+    resolve(UpdateUserTimezone::class)->handle($user, null, true);
+
+    expect($user->refresh())
+        ->timezone->toBeNull()
+        ->show_local_time->toBeFalse();
+});
diff --git a/tests/Unit/AuthorHover.test.tsx b/tests/Unit/AuthorHover.test.tsx
index b3f463ea3..e962b803d 100644
--- a/tests/Unit/AuthorHover.test.tsx
+++ b/tests/Unit/AuthorHover.test.tsx
@@ -182,6 +182,7 @@ test('suggested user row wraps the author in a user preview anchored to their av
         avatar_url: null,
         lane: 1,
         timezone: null,
+        show_local_time: false,
         followed_by_following_count: 15,
         followers_count: 20,
     } as SuggestedUser;
diff --git a/tests/Unit/CommitThread.test.tsx b/tests/Unit/CommitThread.test.tsx
index 6b948863b..0a31bc5af 100644
--- a/tests/Unit/CommitThread.test.tsx
+++ b/tests/Unit/CommitThread.test.tsx
@@ -30,6 +30,7 @@ const reply = (id: string): Commit =>
             username: 'author',
             lane: 1,
             timezone: null,
+            show_local_time: false,
         },
     }) as Commit;
 
diff --git a/tests/Unit/FollowState.test.tsx b/tests/Unit/FollowState.test.tsx
index c295cd7f2..9fb162f62 100644
--- a/tests/Unit/FollowState.test.tsx
+++ b/tests/Unit/FollowState.test.tsx
@@ -111,6 +111,7 @@ function suggestion(username: string): SuggestedUser {
         avatar_url: null,
         lane: 1,
         timezone: null,
+        show_local_time: false,
         followed_by_following_count: 0,
         followers_count: 0,
     } as unknown as SuggestedUser;
diff --git a/tests/Unit/GuestFollow.test.tsx b/tests/Unit/GuestFollow.test.tsx
index 787bdd560..29fe17024 100644
--- a/tests/Unit/GuestFollow.test.tsx
+++ b/tests/Unit/GuestFollow.test.tsx
@@ -107,6 +107,7 @@ test('a guest following from a profile preview goes to sign in', () => {
         avatar_url: null,
         lane: 1,
         timezone: null,
+        show_local_time: false,
         followers_count: 0,
     } as unknown as User;
 
diff --git a/tests/Unit/Models/UserTest.php b/tests/Unit/Models/UserTest.php
index 507ecf807..ade45090a 100644
--- a/tests/Unit/Models/UserTest.php
+++ b/tests/Unit/Models/UserTest.php
@@ -25,6 +25,7 @@
             'updated_at',
             'has_sponsors_listing',
             'timezone',
+            'show_local_time',
             'lane',
             'has_github_account',
             'live',
diff --git a/tests/Unit/NotificationInbox.test.tsx b/tests/Unit/NotificationInbox.test.tsx
index 231df4a04..581f9d0f3 100644
--- a/tests/Unit/NotificationInbox.test.tsx
+++ b/tests/Unit/NotificationInbox.test.tsx
@@ -20,6 +20,7 @@ const actor: User = {
     company: null,
     has_sponsors_listing: false,
     timezone: null,
+    show_local_time: false,
     has_github_account: true,
     lane: 0,
     created_at: timestamp,
diff --git a/tests/Unit/UtcOffset.test.ts b/tests/Unit/UtcOffset.test.ts
new file mode 100644
index 000000000..c52a27cfe
--- /dev/null
+++ b/tests/Unit/UtcOffset.test.ts
@@ -0,0 +1,25 @@
+import assert from 'node:assert/strict';
+import { test } from 'node:test';
+import { formatUtcOffset } from '../../resources/js/lib/utils.ts';
+
+void test('the offset follows daylight saving time of the timezone', () => {
+    assert.equal(
+        formatUtcOffset(new Date('2026-07-01T12:00:00Z'), 'Europe/Berlin'),
+        'UTC +02:00',
+    );
+    assert.equal(
+        formatUtcOffset(new Date('2026-01-01T12:00:00Z'), 'Europe/Berlin'),
+        'UTC +01:00',
+    );
+    assert.equal(
+        formatUtcOffset(new Date('2026-01-01T12:00:00Z'), 'America/New_York'),
+        'UTC -05:00',
+    );
+});
+
+void test('a timezone without an offset is plain UTC', () => {
+    assert.equal(
+        formatUtcOffset(new Date('2026-07-01T12:00:00Z'), 'UTC'),
+        'UTC',
+    );
+});