diff --git a/src/mail/src/Mailable.php b/src/mail/src/Mailable.php
index ff45b3ccb..058872a6f 100644
--- a/src/mail/src/Mailable.php
+++ b/src/mail/src/Mailable.php
@@ -358,9 +358,10 @@ protected function additionalMessageData(): array
      */
     protected function buildMarkdownHtml(array $viewData): Closure
     {
-        return fn ($data) => $this->markdownRenderer()->render(
+        return fn ($data) => Container::getInstance()->make(Markdown::class)->render(
             $this->markdown,
             array_merge($data, $viewData),
+            theme: $this->markdownTheme()
         );
     }
 
@@ -376,7 +377,7 @@ protected function buildMarkdownText(array $viewData): Closure
                 ]);
             }
 
-            return $this->textView ?? $this->markdownRenderer()->renderText(
+            return $this->textView ?? Container::getInstance()->make(Markdown::class)->renderText(
                 $this->markdown,
                 array_merge($data, $viewData)
             );
@@ -384,18 +385,14 @@ protected function buildMarkdownText(array $viewData): Closure
     }
 
     /**
-     * Resolves a Markdown instance with the mail's theme.
+     * Resolve the Markdown theme for this message.
      */
-    protected function markdownRenderer(): Markdown
+    protected function markdownTheme(): string
     {
-        return tap(Container::getInstance()->make(Markdown::class), function ($markdown) {
-            $markdown->theme(
-                $this->theme ?: Container::getInstance()->make('config')->get(
-                    'mail.markdown.theme',
-                    'default'
-                )
-            );
-        });
+        return $this->theme ?: Container::getInstance()->make('config')->get(
+            'mail.markdown.theme',
+            'default'
+        );
     }
 
     /**
diff --git a/src/mail/src/Markdown.php b/src/mail/src/Markdown.php
index b9129f56f..5edddd980 100644
--- a/src/mail/src/Markdown.php
+++ b/src/mail/src/Markdown.php
@@ -46,20 +46,26 @@ public function __construct(
     /**
      * Render the Markdown template into HTML.
      */
-    public function render(string $view, array $data = [], mixed $inliner = null): HtmlString
+    public function render(string $view, array $data = [], mixed $inliner = null, ?string $theme = null): HtmlString
     {
-        $this->view->flushFinderCache();
+        $viewFactory = $this->viewFactoryWithMailNamespace($this->htmlComponentPaths());
 
-        $bladeCompiler = $this->view
+        $bladeCompiler = $viewFactory
             ->getEngineResolver() // @phpstan-ignore method.notFound
             ->resolve('blade')
             ->getCompiler();
 
         $contents = $bladeCompiler->usingEchoFormat(
             'new \Hypervel\Support\EncodedHtmlString(%s)',
-            function () use ($view, $data) {
-                if (static::$withSecuredEncoding === true) {
-                    EncodedHtmlString::encodeUsing(function ($value) {
+            function () use ($viewFactory, $view, $data) {
+                $render = fn () => $viewFactory->make($view, $data)->render();
+
+                if (static::$withSecuredEncoding === false) {
+                    return $render();
+                }
+
+                return EncodedHtmlString::withEncoding(
+                    function ($value) {
                         $replacements = [
                             '[' => '\[',
                             '<' => '&lt;',
@@ -67,33 +73,25 @@ function () use ($view, $data) {
                         ];
 
                         return str_replace(array_keys($replacements), array_values($replacements), $value);
-                    });
-                }
-
-                try {
-                    $contents = $this->view->replaceNamespace(
-                        'mail',
-                        $this->htmlComponentPaths()
-                    )->make($view, $data)->render();
-                } finally {
-                    EncodedHtmlString::flushState();
-                }
-
-                return $contents;
+                    },
+                    $render
+                );
             }
         );
 
-        if ($this->view->exists($customTheme = Str::start($this->theme, 'mail.'))) {
+        $theme ??= $this->theme;
+
+        if ($viewFactory->exists($customTheme = Str::start($theme, 'mail.'))) {
             $theme = $customTheme;
         } else {
-            $theme = str_contains($this->theme, '::')
-                ? $this->theme
-                : 'mail::themes.' . $this->theme;
+            $theme = str_contains($theme, '::')
+                ? $theme
+                : 'mail::themes.' . $theme;
         }
 
         return new HtmlString(($inliner ?: new CssToInlineStyles)->convert(
             str_replace('\[', '[', $contents),
-            $this->view->make($theme, $data)->render()
+            $viewFactory->make($theme, $data)->render()
         ));
     }
 
@@ -102,12 +100,9 @@ function () use ($view, $data) {
      */
     public function renderText(string $view, array $data = []): HtmlString
     {
-        $this->view->flushFinderCache();
-
-        $contents = $this->view->replaceNamespace(
-            'mail',
-            $this->textComponentPaths()
-        )->make($view, $data)->render();
+        $contents = $this->viewFactoryWithMailNamespace($this->textComponentPaths())
+            ->make($view, $data)
+            ->render();
 
         return new HtmlString(
             html_entity_decode(preg_replace("/[\r\n]{2,}/", "\n\n", $contents), ENT_QUOTES, 'UTF-8')
@@ -123,28 +118,21 @@ public static function parse(Stringable|string $text, bool $encoded = false): Ht
             return new HtmlString(static::converter()->convert((string) $text)->getContent());
         }
 
-        EncodedHtmlString::encodeUsing(function ($value) {
-            $replacements = [
-                '[' => '\[',
-                '<' => '\<',
-            ];
+        return new HtmlString(EncodedHtmlString::withEncoding(
+            function ($value) {
+                $replacements = [
+                    '[' => '\[',
+                    '<' => '\<',
+                ];
 
-            $html = str_replace(array_keys($replacements), array_values($replacements), $value);
+                $html = str_replace(array_keys($replacements), array_values($replacements), $value);
 
-            return static::converter([
-                'html_input' => 'escape',
-            ])->convert($html)->getContent();
-        });
-
-        $html = '';
-
-        try {
-            $html = static::converter()->convert((string) $text)->getContent();
-        } finally {
-            EncodedHtmlString::flushState();
-        }
-
-        return new HtmlString($html);
+                return static::converter([
+                    'html_input' => 'escape',
+                ])->convert($html)->getContent();
+            },
+            fn () => static::converter()->convert((string) $text)->getContent()
+        ));
     }
 
     /**
@@ -186,6 +174,20 @@ public function textComponentPaths(): array
         }, $this->componentPaths());
     }
 
+    /**
+     * Clone the view factory with render-local mail component paths.
+     */
+    protected function viewFactoryWithMailNamespace(array $paths): ViewFactory
+    {
+        // Markdown swaps mail:: between HTML and text component paths while
+        // rendering. Keep that namespace change on a short-lived clone so the
+        // singleton view finder stays untouched for concurrent coroutines.
+        $viewFactory = clone $this->view;
+        $viewFactory->replaceNamespace('mail', $paths);
+
+        return $viewFactory;
+    }
+
     /**
      * Get the component paths.
      */
@@ -198,6 +200,9 @@ protected function componentPaths(): array
 
     /**
      * Register new mail component paths.
+     *
+     * Boot-only. Mutates the shared Markdown renderer's component paths; use
+     * scoped view namespaces for per-render component path changes.
      */
     public function loadComponentsFrom(array $paths = []): void
     {
@@ -206,6 +211,9 @@ public function loadComponentsFrom(array $paths = []): void
 
     /**
      * Set the default theme to be used.
+     *
+     * Boot-only. Mutates the shared Markdown renderer's default theme; pass a
+     * per-render theme to render() for message-specific themes.
      */
     public function theme(string $theme): static
     {
@@ -246,6 +254,9 @@ public static function withoutSecuredEncoding(): void
 
     /**
      * Flush the class's global state.
+     *
+     * Boot or tests only. Clears worker-wide Markdown flags; concurrent renders
+     * may switch encoding behavior depending on timing.
      */
     public static function flushState(): void
     {
diff --git a/src/notifications/src/Channels/MailChannel.php b/src/notifications/src/Channels/MailChannel.php
index 38a6739a8..8786a2e69 100644
--- a/src/notifications/src/Channels/MailChannel.php
+++ b/src/notifications/src/Channels/MailChannel.php
@@ -85,9 +85,10 @@ protected function buildView(MailMessage $message): array|string
      */
     protected function buildMarkdownHtml(MailMessage $message): Closure
     {
-        return fn ($data) => $this->markdownRenderer($message)->render(
+        return fn ($data) => $this->markdown->render(
             $message->markdown,
             array_merge($data, $message->data()),
+            theme: $this->markdownTheme($message)
         );
     }
 
@@ -96,23 +97,21 @@ protected function buildMarkdownHtml(MailMessage $message): Closure
      */
     protected function buildMarkdownText(MailMessage $message): Closure
     {
-        return fn ($data) => $this->markdownRenderer($message)->renderText(
+        return fn ($data) => $this->markdown->renderText(
             $message->markdown,
             array_merge($data, $message->data()),
         );
     }
 
     /**
-     * Get the Markdown implementation.
+     * Resolve the Markdown theme for the notification.
      */
-    protected function markdownRenderer(MailMessage $message): Markdown
+    protected function markdownTheme(MailMessage $message): string
     {
         $config = Container::getInstance()
             ->make('config');
 
-        $theme = $message->theme ?? $config->get('mail.markdown.theme', 'default');
-
-        return $this->markdown->theme($theme);
+        return $message->theme ?? $config->get('mail.markdown.theme', 'default');
     }
 
     /**
diff --git a/src/notifications/src/Messages/MailMessage.php b/src/notifications/src/Messages/MailMessage.php
index a6caa7d7b..8e683336f 100644
--- a/src/notifications/src/Messages/MailMessage.php
+++ b/src/notifications/src/Messages/MailMessage.php
@@ -317,8 +317,11 @@ public function render(): string
         $markdown = Container::getInstance()
             ->make(Markdown::class);
 
-        return (string) $markdown->theme($this->theme ?: $markdown->getTheme())
-            ->render($this->markdown, $this->data());
+        return (string) $markdown->render(
+            $this->markdown,
+            $this->data(),
+            theme: $this->theme ?: $markdown->getTheme()
+        );
     }
 
     /**
diff --git a/src/support/src/EncodedHtmlString.php b/src/support/src/EncodedHtmlString.php
index bcd80346a..ed14bba94 100644
--- a/src/support/src/EncodedHtmlString.php
+++ b/src/support/src/EncodedHtmlString.php
@@ -6,12 +6,18 @@
 
 use BackedEnum;
 use Closure;
+use Hypervel\Context\CoroutineContext;
 use Hypervel\Contracts\Support\DeferringDisplayableValue;
 use Hypervel\Contracts\Support\Htmlable;
 use Override;
 
 class EncodedHtmlString extends HtmlString
 {
+    /**
+     * Context key for temporarily scoped encoder callbacks.
+     */
+    protected const ENCODER_CONTEXT_KEY = '__support.encoded_html.encoder';
+
     /**
      * The callback that should be used to encode the HTML strings.
      */
@@ -57,7 +63,9 @@ public function toHtml(): string
             $value = $value->value;
         }
 
-        return (static::$encodeUsingFactory ?? function ($value, $doubleEncode) {
+        $factory = CoroutineContext::get(self::ENCODER_CONTEXT_KEY) ?? static::$encodeUsingFactory;
+
+        return ($factory ?? function ($value, $doubleEncode) {
             return static::convert($value, doubleEncode: $doubleEncode);
         })($value, $this->doubleEncode);
     }
@@ -73,6 +81,29 @@ public static function encodeUsing(?callable $factory = null): void
         static::$encodeUsingFactory = $factory;
     }
 
+    /**
+     * Execute the given callback using a temporary encoder.
+     */
+    public static function withEncoding(callable $factory, callable $callback): mixed
+    {
+        // Preserve an outer scoped encoder so nested Markdown renders restore
+        // the previous coroutine-local state instead of falling back globally.
+        $hadPreviousFactory = CoroutineContext::has(self::ENCODER_CONTEXT_KEY);
+        $previousFactory = CoroutineContext::get(self::ENCODER_CONTEXT_KEY);
+
+        CoroutineContext::set(self::ENCODER_CONTEXT_KEY, $factory);
+
+        try {
+            return $callback();
+        } finally {
+            if ($hadPreviousFactory) {
+                CoroutineContext::set(self::ENCODER_CONTEXT_KEY, $previousFactory);
+            } else {
+                CoroutineContext::forget(self::ENCODER_CONTEXT_KEY);
+            }
+        }
+    }
+
     /**
      * Flush the class's global state.
      *
@@ -82,5 +113,6 @@ public static function encodeUsing(?callable $factory = null): void
     public static function flushState(): void
     {
         static::$encodeUsingFactory = null;
+        CoroutineContext::forget(self::ENCODER_CONTEXT_KEY);
     }
 }
diff --git a/src/view/src/Compilers/ComponentTagCompiler.php b/src/view/src/Compilers/ComponentTagCompiler.php
index 5bb79c5d2..3f342b73a 100644
--- a/src/view/src/Compilers/ComponentTagCompiler.php
+++ b/src/view/src/Compilers/ComponentTagCompiler.php
@@ -235,8 +235,10 @@ protected function componentString(string $component, array $attributes): string
         // component and pass the component as a view parameter to the data so it
         // can be accessed within the component and we can render out the view.
         if (! class_exists($class)) {
+            // Markdown renders mail components through cloned view factories, so
+            // mail:: tags must resolve through the current $__env, not the singleton.
             $view = Str::startsWith($component, 'mail::')
-                ? "\$__env->getContainer()->make(Hypervel\\View\\Factory::class)->make('{$component}')"
+                ? "\$__env->make('{$component}')"
                 : "'{$class}'";
 
             $parameters = [
diff --git a/src/view/src/Factory.php b/src/view/src/Factory.php
index 85af40613..92b73513d 100755
--- a/src/view/src/Factory.php
+++ b/src/view/src/Factory.php
@@ -94,6 +94,17 @@ public function __construct(
         $this->share('__env', $this);
     }
 
+    /**
+     * Clone the factory for isolated render-time namespace changes.
+     */
+    public function __clone(): void
+    {
+        // Cloned factories may change namespace hints for one render; the
+        // singleton finder and Blade's $__env shared binding must stay isolated.
+        $this->finder = clone $this->finder;
+        $this->shared['__env'] = $this;
+    }
+
     /**
      * Get the evaluated view contents for the given view.
      */
diff --git a/tests/Integration/Mail/SendingMarkdownMailTest.php b/tests/Integration/Mail/SendingMarkdownMailTest.php
index cbef1a7e1..6e8ffbd24 100644
--- a/tests/Integration/Mail/SendingMarkdownMailTest.php
+++ b/tests/Integration/Mail/SendingMarkdownMailTest.php
@@ -146,7 +146,7 @@ public function testTheme()
         $this->assertSame('default', $this->app->make(Markdown::class)->getTheme());
 
         Mail::to('test@mail.com')->send(new MarkdownBasicMailableWithTheme);
-        $this->assertSame('taylor', $this->app->make(Markdown::class)->getTheme());
+        $this->assertSame('default', $this->app->make(Markdown::class)->getTheme());
 
         Mail::to('test@mail.com')->send(new MarkdownBasicMailable);
         $this->assertSame('default', $this->app->make(Markdown::class)->getTheme());
diff --git a/tests/Integration/Notifications/SendingMailNotificationsTest.php b/tests/Integration/Notifications/SendingMailNotificationsTest.php
index 5c65af7ec..dd31a2fd9 100644
--- a/tests/Integration/Notifications/SendingMailNotificationsTest.php
+++ b/tests/Integration/Notifications/SendingMailNotificationsTest.php
@@ -72,8 +72,9 @@ public function testMailIsSent()
             'email' => 'taylor@laravel.com',
         ]);
 
-        $this->markdown->shouldReceive('theme')->twice()->with('default')->andReturn($this->markdown);
-        $this->markdown->shouldReceive('render')->once()->andReturn(new HtmlString('htmlContent'));
+        $this->markdown->shouldReceive('render')->once()
+            ->withArgs(fn (...$args) => ($args['theme'] ?? $args[3] ?? null) === 'default')
+            ->andReturn(new HtmlString('htmlContent'));
         $this->markdown->shouldReceive('renderText')->once()->andReturn(new HtmlString('textContent'));
 
         $this->setMailerSendAssertions($notification, $user, function ($closure) {
@@ -110,8 +111,9 @@ public function testMailIsSentWithCustomTheme()
             'email' => 'taylor@laravel.com',
         ]);
 
-        $this->markdown->shouldReceive('theme')->twice()->with('my-custom-theme')->andReturn($this->markdown);
-        $this->markdown->shouldReceive('render')->once()->andReturn(new HtmlString('htmlContent'));
+        $this->markdown->shouldReceive('render')->once()
+            ->withArgs(fn (...$args) => ($args['theme'] ?? $args[3] ?? null) === 'my-custom-theme')
+            ->andReturn(new HtmlString('htmlContent'));
         $this->markdown->shouldReceive('renderText')->once()->andReturn(new HtmlString('textContent'));
 
         $this->setMailerSendAssertions($notification, $user, function ($closure) {
@@ -184,8 +186,9 @@ public function testMailIsSentToNamedAddress()
             'name' => 'Taylor Otwell',
         ]);
 
-        $this->markdown->shouldReceive('theme')->twice()->with('default')->andReturn($this->markdown);
-        $this->markdown->shouldReceive('render')->once()->andReturn(new HtmlString('htmlContent'));
+        $this->markdown->shouldReceive('render')->once()
+            ->withArgs(fn (...$args) => ($args['theme'] ?? $args[3] ?? null) === 'default')
+            ->andReturn(new HtmlString('htmlContent'));
         $this->markdown->shouldReceive('renderText')->once()->andReturn(new HtmlString('textContent'));
 
         $this->setMailerSendAssertions($notification, $user, function ($closure) {
@@ -222,8 +225,9 @@ public function testMailIsSentWithSubject()
             'email' => 'taylor@laravel.com',
         ]);
 
-        $this->markdown->shouldReceive('theme')->with('default')->twice()->andReturn($this->markdown);
-        $this->markdown->shouldReceive('render')->once()->andReturn(new HtmlString('htmlContent'));
+        $this->markdown->shouldReceive('render')->once()
+            ->withArgs(fn (...$args) => ($args['theme'] ?? $args[3] ?? null) === 'default')
+            ->andReturn(new HtmlString('htmlContent'));
         $this->markdown->shouldReceive('renderText')->once()->andReturn(new HtmlString('textContent'));
 
         $this->setMailerSendAssertions($notification, $user, function ($closure) {
@@ -250,8 +254,9 @@ public function testMailIsSentToMultipleAddresses()
             'email' => 'taylor@laravel.com',
         ]);
 
-        $this->markdown->shouldReceive('theme')->with('default')->twice()->andReturn($this->markdown);
-        $this->markdown->shouldReceive('render')->once()->andReturn(new HtmlString('htmlContent'));
+        $this->markdown->shouldReceive('render')->once()
+            ->withArgs(fn (...$args) => ($args['theme'] ?? $args[3] ?? null) === 'default')
+            ->andReturn(new HtmlString('htmlContent'));
         $this->markdown->shouldReceive('renderText')->once()->andReturn(new HtmlString('textContent'));
 
         $this->setMailerSendAssertions($notification, $user, function ($closure) {
diff --git a/tests/Mail/Fixtures/Markdown/components/html/layout.blade.php b/tests/Mail/Fixtures/Markdown/components/html/layout.blade.php
new file mode 100644
index 000000000..a67e85811
--- /dev/null
+++ b/tests/Mail/Fixtures/Markdown/components/html/layout.blade.php
@@ -0,0 +1,2 @@
+html-layout
+{{ $slot }}
diff --git a/tests/Mail/Fixtures/Markdown/components/html/probe.blade.php b/tests/Mail/Fixtures/Markdown/components/html/probe.blade.php
new file mode 100644
index 000000000..634ea66c6
--- /dev/null
+++ b/tests/Mail/Fixtures/Markdown/components/html/probe.blade.php
@@ -0,0 +1,3 @@
+html-start
+<?php usleep(5000); ?>
+html-end
diff --git a/tests/Mail/Fixtures/Markdown/components/html/themes/default.css b/tests/Mail/Fixtures/Markdown/components/html/themes/default.css
new file mode 100644
index 000000000..224a49076
--- /dev/null
+++ b/tests/Mail/Fixtures/Markdown/components/html/themes/default.css
@@ -0,0 +1 @@
+theme-css
diff --git a/tests/Mail/Fixtures/Markdown/components/text/probe.blade.php b/tests/Mail/Fixtures/Markdown/components/text/probe.blade.php
new file mode 100644
index 000000000..90da157ff
--- /dev/null
+++ b/tests/Mail/Fixtures/Markdown/components/text/probe.blade.php
@@ -0,0 +1,3 @@
+text-start
+<?php usleep(5000); ?>
+text-end
diff --git a/tests/Mail/Fixtures/Markdown/views/component-tag.blade.php b/tests/Mail/Fixtures/Markdown/views/component-tag.blade.php
new file mode 100644
index 000000000..58b4ab34a
--- /dev/null
+++ b/tests/Mail/Fixtures/Markdown/views/component-tag.blade.php
@@ -0,0 +1,3 @@
+<x-mail::layout>
+Component Body
+</x-mail::layout>
diff --git a/tests/Mail/MailMarkdownTest.php b/tests/Mail/MailMarkdownTest.php
index 8991496bb..1816cef4e 100644
--- a/tests/Mail/MailMarkdownTest.php
+++ b/tests/Mail/MailMarkdownTest.php
@@ -29,7 +29,6 @@ public function testRenderFunctionReturnsHtml()
             ->andReturnUsing(fn ($echoFormat, $callback) => $callback());
 
         $markdown = new Markdown($viewFactory);
-        $viewFactory->shouldReceive('flushFinderCache')->once();
         $viewFactory->shouldReceive('replaceNamespace')->once()->with('mail', $markdown->htmlComponentPaths())->andReturnSelf();
         $viewFactory->shouldReceive('exists')->with('mail.default')->andReturn(false);
         $viewFactory->shouldReceive('make')->with('view', [])->andReturn($viewInterface);
@@ -56,7 +55,6 @@ public function testRenderFunctionReturnsHtmlWithCustomTheme()
 
         $markdown = new Markdown($viewFactory);
         $markdown->theme('yaz');
-        $viewFactory->shouldReceive('flushFinderCache')->once();
         $viewFactory->shouldReceive('replaceNamespace')->once()->with('mail', $markdown->htmlComponentPaths())->andReturnSelf();
         $viewFactory->shouldReceive('exists')->with('mail.yaz')->andReturn(true);
         $viewFactory->shouldReceive('make')->with('view', [])->andReturn($viewInterface);
@@ -83,7 +81,6 @@ public function testRenderFunctionReturnsHtmlWithCustomThemeWithMailPrefix()
 
         $markdown = new Markdown($viewFactory);
         $markdown->theme('mail.yaz');
-        $viewFactory->shouldReceive('flushFinderCache')->once();
         $viewFactory->shouldReceive('replaceNamespace')->once()->with('mail', $markdown->htmlComponentPaths())->andReturnSelf();
         $viewFactory->shouldReceive('exists')->with('mail.yaz')->andReturn(true);
         $viewFactory->shouldReceive('make')->with('view', [])->andReturn($viewInterface);
@@ -101,7 +98,6 @@ public function testRenderTextReturnsText()
 
         $viewFactory = m::mock(ViewFactory::class);
         $markdown = new Markdown($viewFactory);
-        $viewFactory->shouldReceive('flushFinderCache')->once();
         $viewFactory->shouldReceive('replaceNamespace')->once()->with('mail', $markdown->textComponentPaths())->andReturnSelf();
         $viewFactory->shouldReceive('make')->with('view', [])->andReturn($viewInterface);
 
diff --git a/tests/Mail/MarkdownCoroutineSafetyTest.php b/tests/Mail/MarkdownCoroutineSafetyTest.php
new file mode 100644
index 000000000..3682a0a55
--- /dev/null
+++ b/tests/Mail/MarkdownCoroutineSafetyTest.php
@@ -0,0 +1,441 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Hypervel\Tests\Mail;
+
+use Closure;
+use Hypervel\Config\Repository;
+use Hypervel\Container\Container;
+use Hypervel\Contracts\Foundation\Application as ApplicationContract;
+use Hypervel\Contracts\Mail\Factory as MailFactory;
+use Hypervel\Contracts\Support\Arrayable;
+use Hypervel\Contracts\View\Factory as ViewFactoryContract;
+use Hypervel\Contracts\View\View as ViewContract;
+use Hypervel\Events\Dispatcher;
+use Hypervel\Filesystem\Filesystem;
+use Hypervel\Mail\Mailable;
+use Hypervel\Mail\Markdown;
+use Hypervel\Notifications\Channels\MailChannel;
+use Hypervel\Notifications\Messages\MailMessage as NotificationMailMessage;
+use Hypervel\Support\EncodedHtmlString;
+use Hypervel\Support\HtmlString;
+use Hypervel\Tests\TestCase;
+use Hypervel\View\Compilers\BladeCompiler;
+use Hypervel\View\Engines\CompilerEngine;
+use Hypervel\View\Engines\EngineResolver;
+use Hypervel\View\Engines\FileEngine;
+use Hypervel\View\Engines\PhpEngine;
+use Hypervel\View\Factory as ViewFactory;
+use Hypervel\View\FileViewFinder;
+use Mockery as m;
+
+use function Hypervel\Coroutine\parallel;
+
+class MarkdownCoroutineSafetyTest extends TestCase
+{
+    protected function tearDown(): void
+    {
+        Container::setInstance(null);
+        Markdown::flushState();
+        EncodedHtmlString::flushState();
+
+        parent::tearDown();
+    }
+
+    public function testRenderDoesNotClearBootEncoder(): void
+    {
+        EncodedHtmlString::encodeUsing(fn ($value) => "boot:{$value}");
+
+        $markdown = new Markdown(new MarkdownTestViewFactory(
+            fn () => (new EncodedHtmlString('rendered'))->toHtml()
+        ));
+
+        $this->assertSame('boot:rendered', $markdown->render('view', inliner: new MarkdownPassthroughInliner)->toHtml());
+        $this->assertSame('boot:after', (new EncodedHtmlString('after'))->toHtml());
+    }
+
+    public function testEncodedParseDoesNotClearBootEncoder(): void
+    {
+        EncodedHtmlString::encodeUsing(fn ($value) => "boot:{$value}");
+
+        $html = Markdown::parse(new EncodedHtmlString('Visit <span>https://hypervel.org/docs</span>'), encoded: true);
+
+        $this->assertStringContainsString('Visit &lt;span&gt;https://hypervel.org/docs&lt;/span&gt;', $html->toHtml());
+        $this->assertSame('boot:after', (new EncodedHtmlString('after'))->toHtml());
+    }
+
+    public function testSecuredRenderEncodingIsIsolatedBetweenCoroutines(): void
+    {
+        Markdown::withSecuredEncoding();
+
+        $results = parallel([
+            'a' => fn () => $this->renderEncodingProbe(),
+            'b' => fn () => $this->renderEncodingProbe(),
+        ]);
+
+        $this->assertSame('scoped:scoped', $results['a']);
+        $this->assertSame('scoped:scoped', $results['b']);
+    }
+
+    public function testRenderUsesPerCallThemeWithoutMutatingDefaultTheme(): void
+    {
+        $markdown = new Markdown(new MarkdownTestViewFactory(
+            fn () => 'content',
+            fn (string $view) => $view
+        ));
+        $markdown->theme('default-a');
+
+        $this->assertSame('content|theme:mail::themes.theme-b', $markdown->render(
+            'view',
+            inliner: new MarkdownPassthroughInliner,
+            theme: 'theme-b'
+        )->toHtml());
+        $this->assertSame('default-a', $markdown->getTheme());
+    }
+
+    public function testRenderDoesNotFlushUnrelatedFinderCache(): void
+    {
+        $factory = new MarkdownTestViewFactory(fn () => 'content');
+        $factory->cacheView('unrelated', '/cached/unrelated.php');
+
+        $markdown = new Markdown($factory);
+
+        $markdown->render('view', inliner: new MarkdownPassthroughInliner);
+
+        $this->assertSame('/cached/unrelated.php', $factory->cachedView('unrelated'));
+    }
+
+    public function testRenderAndRenderTextUseIsolatedMailNamespaces(): void
+    {
+        $markdown = new Markdown($this->makeRealViewFactory(), [
+            'paths' => [$this->markdownComponentsPath()],
+        ]);
+
+        $results = parallel([
+            'html' => fn () => $markdown->render('mail::probe', inliner: new MarkdownPassthroughInliner)->toHtml(),
+            'text' => fn () => $markdown->renderText('mail::probe')->toHtml(),
+        ]);
+
+        $this->assertStringContainsString('html-start', $results['html']);
+        $this->assertStringContainsString('html-end', $results['html']);
+        $this->assertStringNotContainsString('text-start', $results['html']);
+        $this->assertStringContainsString('text-start', $results['text']);
+        $this->assertStringContainsString('text-end', $results['text']);
+        $this->assertStringNotContainsString('html-start', $results['text']);
+    }
+
+    public function testMailComponentTagsResolveThroughClonedFactory(): void
+    {
+        $markdown = new Markdown($this->makeRealViewFactory(), [
+            'paths' => [$this->markdownComponentsPath()],
+        ]);
+
+        $result = $markdown->render('component-tag', inliner: new MarkdownPassthroughInliner)->toHtml();
+
+        $this->assertStringContainsString('html-layout', $result);
+        $this->assertStringContainsString('Component Body', $result);
+    }
+
+    public function testConcurrentMailablesUseTheirOwnThemes(): void
+    {
+        $markdown = $this->swapThemeProbeMarkdownIntoContainer();
+
+        $results = parallel([
+            'a' => fn () => (new ThemeProbeMailable('theme-a'))->renderProbe(),
+            'b' => fn () => (new ThemeProbeMailable('theme-b'))->renderProbe(),
+        ]);
+
+        $this->assertSame('theme-a:theme-a', $results['a']);
+        $this->assertSame('theme-b:theme-b', $results['b']);
+        $this->assertSame('default', $markdown->getTheme());
+    }
+
+    public function testMailMessageRenderUsesThemeWithoutMutatingMarkdownSingleton(): void
+    {
+        $markdown = $this->swapThemeProbeMarkdownIntoContainer();
+
+        $message = (new NotificationMailMessage)->theme('theme-a');
+
+        $this->assertSame('theme-a:theme-a', $message->render());
+        $this->assertSame('default', $markdown->getTheme());
+    }
+
+    public function testMailChannelUsesNotificationThemeWithoutMutatingMarkdownSingleton(): void
+    {
+        $markdown = $this->swapThemeProbeMarkdownIntoContainer();
+        $channel = new ThemeProbeMailChannel(m::mock(MailFactory::class), $markdown);
+        $message = (new NotificationMailMessage)->theme('theme-a');
+
+        $this->assertSame('theme-a:theme-a', $channel->renderHtml($message));
+        $this->assertSame('default', $markdown->getTheme());
+    }
+
+    protected function swapThemeProbeMarkdownIntoContainer(): ThemeProbeMarkdown
+    {
+        $container = new Container;
+        $markdown = new ThemeProbeMarkdown;
+
+        $container->instance('config', new Repository([
+            'mail' => [
+                'markdown' => [
+                    'theme' => 'default',
+                ],
+            ],
+        ]));
+        $container->instance(Markdown::class, $markdown);
+
+        Container::setInstance($container);
+
+        return $markdown;
+    }
+
+    protected function renderEncodingProbe(): string
+    {
+        $markdown = new Markdown(new MarkdownTestViewFactory(function () {
+            $before = $this->encodingMarker();
+            usleep(5000);
+
+            return $before . ':' . $this->encodingMarker();
+        }));
+
+        return $markdown->render('view', inliner: new MarkdownPassthroughInliner)->toHtml();
+    }
+
+    protected function encodingMarker(): string
+    {
+        return (new EncodedHtmlString('['))->toHtml() === '\['
+            ? 'scoped'
+            : 'default';
+    }
+
+    protected function makeRealViewFactory(): ViewFactory
+    {
+        $container = new Container;
+        $filesystem = new Filesystem;
+        $resolver = new EngineResolver;
+        $application = m::mock(ApplicationContract::class);
+        $compiledPath = sys_get_temp_dir() . '/hypervel-markdown-coroutine-safety-views';
+        $bladeCompiler = new BladeCompiler($filesystem, $compiledPath, shouldCache: false);
+
+        $application->shouldReceive('getNamespace')->andReturn('App\\');
+        $filesystem->ensureDirectoryExists($compiledPath);
+
+        $resolver->register('blade', fn () => new CompilerEngine($bladeCompiler, $filesystem));
+        $resolver->register('file', fn () => new FileEngine($filesystem));
+        $resolver->register('php', fn () => new PhpEngine($filesystem));
+
+        $factory = new ViewFactory(
+            $resolver,
+            new FileViewFinder($filesystem, [$this->markdownViewsPath()]),
+            new Dispatcher($container)
+        );
+
+        $factory->setContainer($container);
+        $container->instance(ApplicationContract::class, $application);
+        $container->instance(ViewFactory::class, $factory);
+        $container->instance(ViewFactoryContract::class, $factory);
+        Container::setInstance($container);
+
+        return $factory;
+    }
+
+    protected function markdownViewsPath(): string
+    {
+        return __DIR__ . '/Fixtures/Markdown/views';
+    }
+
+    protected function markdownComponentsPath(): string
+    {
+        return __DIR__ . '/Fixtures/Markdown/components';
+    }
+}
+
+class MarkdownTestViewFactory implements ViewFactoryContract
+{
+    protected array $cachedViews = [];
+
+    public function __construct(
+        protected Closure $renderer,
+        protected ?Closure $themeRenderer = null
+    ) {
+    }
+
+    public function exists(string $view): bool
+    {
+        return false;
+    }
+
+    public function file(string $path, Arrayable|array $data = [], array $mergeData = []): ViewContract
+    {
+        return $this->make($path, $data, $mergeData);
+    }
+
+    public function make(string $view, Arrayable|array $data = [], array $mergeData = []): ViewContract
+    {
+        if (str_starts_with($view, 'mail::themes.')) {
+            return new MarkdownTestView(fn () => is_null($this->themeRenderer)
+                ? ''
+                : call_user_func($this->themeRenderer, $view));
+        }
+
+        return new MarkdownTestView($this->renderer);
+    }
+
+    public function first(array $views, Arrayable|array $data = [], array $mergeData = []): ViewContract
+    {
+        return $this->make($views[0], $data, $mergeData);
+    }
+
+    public function share(array|string $key, mixed $value = null): mixed
+    {
+        return null;
+    }
+
+    public function composer(array|string $views, Closure|string $callback): array
+    {
+        return [];
+    }
+
+    public function creator(array|string $views, Closure|string $callback): array
+    {
+        return [];
+    }
+
+    public function addNamespace(string $namespace, string|array $hints): static
+    {
+        return $this;
+    }
+
+    public function replaceNamespace(string $namespace, string|array $hints): static
+    {
+        return $this;
+    }
+
+    public function flushFinderCache(): void
+    {
+        $this->cachedViews = [];
+    }
+
+    public function getEngineResolver(): MarkdownTestEngineResolver
+    {
+        return new MarkdownTestEngineResolver;
+    }
+
+    public function cacheView(string $name, string $path): void
+    {
+        $this->cachedViews[$name] = $path;
+    }
+
+    public function cachedView(string $name): ?string
+    {
+        return $this->cachedViews[$name] ?? null;
+    }
+}
+
+class MarkdownTestEngineResolver
+{
+    public function resolve(string $engine): MarkdownTestCompilerEngine
+    {
+        return new MarkdownTestCompilerEngine;
+    }
+}
+
+class MarkdownTestCompilerEngine
+{
+    public function getCompiler(): MarkdownTestBladeCompiler
+    {
+        return new MarkdownTestBladeCompiler;
+    }
+}
+
+class MarkdownTestBladeCompiler
+{
+    public function usingEchoFormat(string $format, callable $callback): string
+    {
+        return $callback();
+    }
+}
+
+class MarkdownTestView implements ViewContract
+{
+    public function __construct(protected Closure $renderer)
+    {
+    }
+
+    public function render(): string
+    {
+        return call_user_func($this->renderer);
+    }
+
+    public function name(): string
+    {
+        return 'view';
+    }
+
+    public function with(string|array $key, mixed $value = null): static
+    {
+        return $this;
+    }
+
+    public function getData(): array
+    {
+        return [];
+    }
+
+    public function getPath(): string
+    {
+        return __FILE__;
+    }
+}
+
+class MarkdownPassthroughInliner
+{
+    public function convert(string $html, string $css): string
+    {
+        return $css === '' ? $html : "{$html}|theme:{$css}";
+    }
+}
+
+class ThemeProbeMarkdown extends Markdown
+{
+    public function __construct()
+    {
+    }
+
+    public function render(string $view, array $data = [], mixed $inliner = null, ?string $theme = null): HtmlString
+    {
+        $before = $theme ?? $this->getTheme();
+        usleep(5000);
+
+        return new HtmlString($before . ':' . ($theme ?? $this->getTheme()));
+    }
+
+    public function renderText(string $view, array $data = []): HtmlString
+    {
+        return new HtmlString('text');
+    }
+}
+
+class ThemeProbeMailable extends Mailable
+{
+    public string $markdown = 'message';
+
+    public function __construct(string $theme)
+    {
+        $this->theme = $theme;
+    }
+
+    public function renderProbe(): string
+    {
+        return $this->buildMarkdownHtml([])([])->toHtml();
+    }
+}
+
+class ThemeProbeMailChannel extends MailChannel
+{
+    public function renderHtml(NotificationMailMessage $message): string
+    {
+        return $this->buildMarkdownHtml($message)([])->toHtml();
+    }
+}
diff --git a/tests/Support/SupportEncodedHtmlStringTest.php b/tests/Support/SupportEncodedHtmlStringTest.php
new file mode 100644
index 000000000..954744cc3
--- /dev/null
+++ b/tests/Support/SupportEncodedHtmlStringTest.php
@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Hypervel\Tests\Support;
+
+use Hypervel\Support\EncodedHtmlString;
+use Hypervel\Tests\TestCase;
+
+use function Hypervel\Coroutine\parallel;
+
+class SupportEncodedHtmlStringTest extends TestCase
+{
+    protected function tearDown(): void
+    {
+        EncodedHtmlString::flushState();
+
+        parent::tearDown();
+    }
+
+    public function testScopedEncodingOverridesBootEncoderAndRestoresNestedState(): void
+    {
+        EncodedHtmlString::encodeUsing(fn ($value) => "boot:{$value}");
+
+        $result = EncodedHtmlString::withEncoding(
+            fn ($value) => "outer:{$value}",
+            function () {
+                $outerBefore = (new EncodedHtmlString('before'))->toHtml();
+
+                $inner = EncodedHtmlString::withEncoding(
+                    fn ($value) => "inner:{$value}",
+                    fn () => (new EncodedHtmlString('during'))->toHtml()
+                );
+
+                $outerAfter = (new EncodedHtmlString('after'))->toHtml();
+
+                return [$outerBefore, $inner, $outerAfter];
+            }
+        );
+
+        $this->assertSame(['outer:before', 'inner:during', 'outer:after'], $result);
+        $this->assertSame('boot:final', (new EncodedHtmlString('final'))->toHtml());
+    }
+
+    public function testScopedEncodingIsIsolatedBetweenCoroutines(): void
+    {
+        EncodedHtmlString::encodeUsing(fn ($value) => "boot:{$value}");
+
+        $results = parallel([
+            'a' => function () {
+                return EncodedHtmlString::withEncoding(
+                    fn ($value) => "a:{$value}",
+                    function () {
+                        $before = (new EncodedHtmlString('before'))->toHtml();
+                        usleep(5000);
+
+                        return [$before, (new EncodedHtmlString('after'))->toHtml()];
+                    }
+                );
+            },
+            'b' => function () {
+                return EncodedHtmlString::withEncoding(
+                    fn ($value) => "b:{$value}",
+                    function () {
+                        $before = (new EncodedHtmlString('before'))->toHtml();
+                        usleep(5000);
+
+                        return [$before, (new EncodedHtmlString('after'))->toHtml()];
+                    }
+                );
+            },
+        ]);
+
+        $this->assertSame(['a:before', 'a:after'], $results['a']);
+        $this->assertSame(['b:before', 'b:after'], $results['b']);
+        $this->assertSame('boot:final', (new EncodedHtmlString('final'))->toHtml());
+    }
+}
diff --git a/tests/View/ViewFactoryTest.php b/tests/View/ViewFactoryTest.php
index ddf193928..f956e314b 100755
--- a/tests/View/ViewFactoryTest.php
+++ b/tests/View/ViewFactoryTest.php
@@ -19,6 +19,7 @@
 use Hypervel\View\Engines\CompilerEngine;
 use Hypervel\View\Engines\EngineResolver;
 use Hypervel\View\Engines\PhpEngine;
+use Hypervel\View\FileViewFinder;
 use Hypervel\View\Factory;
 use Hypervel\View\View;
 use Hypervel\View\ViewFinderInterface;
@@ -35,6 +36,29 @@ protected function tearDown(): void
         m::close();
     }
 
+    public function testCloneIsolatesFinderAndSharedEnvironment()
+    {
+        $factory = new Factory(
+            m::mock(EngineResolver::class),
+            new FileViewFinder(new Filesystem, [__DIR__ . '/Fixtures']),
+            m::mock(DispatcherContract::class)
+        );
+
+        $clone = clone $factory;
+        $clone->replaceNamespace('foo', __DIR__ . '/Fixtures/namespaced');
+        $clone->share('scoped', 'value');
+
+        $this->assertSame(__DIR__ . '/Fixtures/namespaced/basic.php', $clone->getFinder()->find('foo::basic'));
+        $this->assertSame($factory, $factory->shared('__env'));
+        $this->assertSame($clone, $clone->shared('__env'));
+        $this->assertNull($factory->shared('scoped'));
+
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('No hint path defined for [foo].');
+
+        $factory->getFinder()->find('foo::basic');
+    }
+
     public function testMakeCreatesNewViewInstanceWithProperPathAndEngine()
     {
         unset($_SERVER['__test.view']);