diff --git a/database/2018_05_17_000055_forum_structure.php b/database/2018_05_17_000055_forum_structure.php
index 4b90de14..17f996a7 100644
--- a/database/2018_05_17_000055_forum_structure.php
+++ b/database/2018_05_17_000055_forum_structure.php
@@ -59,6 +59,7 @@ function migrate_up(PDO $conn): void
             `user_id`       INT(10) UNSIGNED    NULL        DEFAULT NULL,
             `post_ip`       BLOB                NOT NULL,
             `post_text`     TEXT                NOT NULL,
+            `post_parse`    TINYINT(4) UNSIGNED NOT NULL    DEFAULT '0',
             `post_created`  TIMESTAMP           NOT NULL    DEFAULT CURRENT_TIMESTAMP,
             `post_edited`   TIMESTAMP           NULL        DEFAULT NULL,
             `post_deleted`  TIMESTAMP           NULL        DEFAULT NULL,
diff --git a/public/forum/posting.php b/public/forum/posting.php
index 6d4608eb..b899cdef 100644
--- a/public/forum/posting.php
+++ b/public/forum/posting.php
@@ -123,7 +123,8 @@ if ($postRequest) {
         $forum['forum_id'],
         $app->getUserId(),
         IPAddress::remote()->getString(),
-        $postText
+        $postText,
+        MSZ_FORUM_POST_PARSER_BBCODE
     );
     forum_topic_mark_read($app->getUserId(), $topicId, $forum['forum_id']);
 
diff --git a/public/index.php b/public/index.php
index c1921365..407e8c9f 100644
--- a/public/index.php
+++ b/public/index.php
@@ -1,5 +1,6 @@
 <?php
 use Misuzu\Database;
+use Misuzu\Parsers\MarkdownParser;
 
 require_once __DIR__ . '/../misuzu.php';
 
diff --git a/src/Application.php b/src/Application.php
index 19da7cd1..c82337f2 100644
--- a/src/Application.php
+++ b/src/Application.php
@@ -246,6 +246,8 @@ class Application extends ApplicationBase
         $this->templatingInstance->addFilter('colour_get_red');
         $this->templatingInstance->addFilter('colour_get_green');
         $this->templatingInstance->addFilter('colour_get_blue');
+        $this->templatingInstance->addFilter('md', 'parse_markdown');
+        $this->templatingInstance->addFilter('bbcode', 'parse_bbcode');
 
         $this->templatingInstance->addFunction('git_hash', [Application::class, 'gitCommitHash']);
         $this->templatingInstance->addFunction('git_branch', [Application::class, 'gitBranch']);
diff --git a/src/Forum/post.php b/src/Forum/post.php
index 3ac50bc9..7ba3720e 100644
--- a/src/Forum/post.php
+++ b/src/Forum/post.php
@@ -1,26 +1,42 @@
 <?php
 use Misuzu\Database;
 
+define('MSZ_FORUM_POST_PARSER_PLAIN', 0);
+define('MSZ_FORUM_POST_PARSER_BBCODE', 1);
+define('MSZ_FORUM_POST_PARSER_MARKDOWN', 2);
+define('MSZ_FORUM_POST_PARSERS', [
+    MSZ_FORUM_POST_PARSER_PLAIN,
+    MSZ_FORUM_POST_PARSER_BBCODE,
+    MSZ_FORUM_POST_PARSER_MARKDOWN,
+]);
+
+function forum_post_is_valid_parser(int $parser): bool
+{
+    return in_array($parser, MSZ_FORUM_POST_PARSERS);
+}
+
 function forum_post_create(
     int $topicId,
     int $forumId,
     int $userId,
     string $ipAddress,
-    string $text
+    string $text,
+    int $parser = MSZ_FORUM_POST_PARSER_PLAIN
 ): int {
     $dbc = Database::connection();
 
     $createPost = $dbc->prepare('
         INSERT INTO `msz_forum_posts`
-            (`topic_id`, `forum_id`, `user_id`, `post_ip`, `post_text`)
+            (`topic_id`, `forum_id`, `user_id`, `post_ip`, `post_text`, `post_parse`)
         VALUES
-            (:topic_id, :forum_id, :user_id, INET6_ATON(:post_ip), :post_text)
+            (:topic_id, :forum_id, :user_id, INET6_ATON(:post_ip), :post_text, :post_parse)
     ');
     $createPost->bindValue('topic_id', $topicId);
     $createPost->bindValue('forum_id', $forumId);
     $createPost->bindValue('user_id', $userId);
     $createPost->bindValue('post_ip', $ipAddress);
     $createPost->bindValue('post_text', $text);
+    $createPost->bindValue('post_parse', $parser);
 
     return $createPost->execute() ? $dbc->lastInsertId() : 0;
 }
@@ -50,7 +66,7 @@ function forum_post_find(int $postId): array
 
 define('MSZ_FORUM_POST_LISTING_QUERY_STANDARD', '
     SELECT
-        p.`post_id`, p.`post_text`, p.`post_created`,
+        p.`post_id`, p.`post_text`, p.`post_created`, p.`post_parse`,
         p.`topic_id`,
         u.`user_id` as `poster_id`,
         u.`username` as `poster_name`,
diff --git a/src/Parsers/BBCode/BBCodeParser.php b/src/Parsers/BBCode/BBCodeParser.php
new file mode 100644
index 00000000..bc242146
--- /dev/null
+++ b/src/Parsers/BBCode/BBCodeParser.php
@@ -0,0 +1,51 @@
+<?php
+namespace Misuzu\Parsers\BBCode;
+
+use Misuzu\Parsers\Parser;
+
+final class BBCodeParser extends Parser
+{
+    private $tags = [];
+
+    public function __construct(array $tags = [])
+    {
+        parent::__construct();
+
+        if (empty($tags)) {
+            $tags = [
+                // Advanced markup
+                new Tags\CodeTag,
+                new Tags\QuoteTag,
+                new Tags\BoxTag,
+                new Tags\MarkdownTag,
+
+                // Slightly more advanced markup
+                new Tags\AudioTag,
+                new Tags\VideoTag,
+
+                // Basic markup
+                new Tags\BoldTag,
+                new Tags\ItalicsTag,
+                new Tags\UnderlineTag,
+                new Tags\StrikeTag,
+                new Tags\SpoilerTag,
+                new Tags\HeaderTag,
+                new Tags\ImageTag,
+
+                // Finally parse leftover newlines
+                new Tags\NewLineTag,
+            ];
+        }
+
+        $this->tags = $tags;
+    }
+
+    public function parseText(string $text): string
+    {
+        foreach ($this->tags as $tag) {
+            $text = $tag->parseText($text);
+        }
+
+        return $text;
+    }
+}
diff --git a/src/Parsers/BBCode/BBCodeSimpleTag.php b/src/Parsers/BBCode/BBCodeSimpleTag.php
new file mode 100644
index 00000000..b8ad6ccb
--- /dev/null
+++ b/src/Parsers/BBCode/BBCodeSimpleTag.php
@@ -0,0 +1,13 @@
+<?php
+namespace Misuzu\Parsers\BBCode;
+
+abstract class BBCodeSimpleTag
+{
+    abstract public function getPattern(): string;
+    abstract public function getReplacement(): string;
+
+    public function parseText(string $text): string
+    {
+        return preg_replace($this->getPattern(), $this->getReplacement(), $text);
+    }
+}
diff --git a/src/Parsers/BBCode/BBCodeTag.php b/src/Parsers/BBCode/BBCodeTag.php
new file mode 100644
index 00000000..5a4d14e5
--- /dev/null
+++ b/src/Parsers/BBCode/BBCodeTag.php
@@ -0,0 +1,7 @@
+<?php
+namespace Misuzu\Parsers\BBCode;
+
+abstract class BBCodeTag
+{
+    abstract public function parseText(string $text): string;
+}
diff --git a/src/Parsers/BBCode/Tags/AudioTag.php b/src/Parsers/BBCode/Tags/AudioTag.php
new file mode 100644
index 00000000..875147cf
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/AudioTag.php
@@ -0,0 +1,20 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeTag;
+
+final class AudioTag extends BBCodeTag
+{
+    public function parseText(string $text): string
+    {
+        return preg_replace_callback(
+            '#\[audio\]((?:https?:\/\/).*)\[/audio\]#',
+            function ($matches) {
+                // todo: domain matches etc.
+                // sites like soundcloud (and mixcloud, if possible) should be embeddable through this tag
+                return "<audio controls src='{$matches[1]}'></audio>";
+            },
+            $text
+        );
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/BoldTag.php b/src/Parsers/BBCode/Tags/BoldTag.php
new file mode 100644
index 00000000..8ac8a299
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/BoldTag.php
@@ -0,0 +1,17 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeSimpleTag;
+
+final class BoldTag extends BBCodeSimpleTag
+{
+    public function getPattern(): string
+    {
+        return "/\[b\](.*)\[\/b\]/";
+    }
+
+    public function getReplacement(): string
+    {
+        return '<b>$1</b>';
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/BoxTag.php b/src/Parsers/BBCode/Tags/BoxTag.php
new file mode 100644
index 00000000..ba54184e
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/BoxTag.php
@@ -0,0 +1,23 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeTag;
+
+final class BoxTag extends BBCodeTag
+{
+    public function parseText(string $text): string
+    {
+        return preg_replace_callback(
+            '/\[box(?:=(.*))?\](.*)\[\/box\]/',
+            function ($matches) {
+                $randomId = 'toggle_' . bin2hex(random_bytes(8));
+                $title = strlen($matches[1]) ? $matches[1] : 'Spoiler';
+                return '<div class="container container--hidden" id="' . $randomId . '">'
+                    . "<div class='container__title' onclick='toggleContainer(\"{$randomId}\")'>{$title}</div>"
+                    . "<div class='container__content'>{$matches[2]}</div>"
+                    . '</div>';
+            },
+            $text
+        );
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/CodeTag.php b/src/Parsers/BBCode/Tags/CodeTag.php
new file mode 100644
index 00000000..0b58af54
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/CodeTag.php
@@ -0,0 +1,20 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeTag;
+
+final class CodeTag extends BBCodeTag
+{
+    public function parseText(string $text): string
+    {
+        return preg_replace_callback(
+            '/\[code(?:\=([a-z]+))?\](.*?)\[\/code\]/s',
+            function ($matches) {
+                $class = strlen($matches[1]) ? "lang-{$matches[1]}" : '';
+                $text = str_replace(['[', ']', '<', '>'], ['&#91;', '&#93;', '&lt;', '&gt;'], $matches[2]);
+                return "<pre class='bbcode__code'><code class='bbcode__code-container {$class}'>{$text}</code></pre>";
+            },
+            $text
+        );
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/HeaderTag.php b/src/Parsers/BBCode/Tags/HeaderTag.php
new file mode 100644
index 00000000..285f41fb
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/HeaderTag.php
@@ -0,0 +1,17 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeSimpleTag;
+
+final class HeaderTag extends BBCodeSimpleTag
+{
+    public function getPattern(): string
+    {
+        return "/\[header\](.*)\[\/header\]/";
+    }
+
+    public function getReplacement(): string
+    {
+        return '<h1>$1</h1>';
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/ImageTag.php b/src/Parsers/BBCode/Tags/ImageTag.php
new file mode 100644
index 00000000..44c0c891
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/ImageTag.php
@@ -0,0 +1,17 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeSimpleTag;
+
+final class ImageTag extends BBCodeSimpleTag
+{
+    public function getPattern(): string
+    {
+        return "/\[img\]((?:https?:\/\/).*)\[\/img\]/";
+    }
+
+    public function getReplacement(): string
+    {
+        return '<img src="$1" alt="$1">';
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/ItalicsTag.php b/src/Parsers/BBCode/Tags/ItalicsTag.php
new file mode 100644
index 00000000..9a09b9ef
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/ItalicsTag.php
@@ -0,0 +1,17 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeSimpleTag;
+
+final class ItalicsTag extends BBCodeSimpleTag
+{
+    public function getPattern(): string
+    {
+        return "/\[i\](.*)\[\/i\]/";
+    }
+
+    public function getReplacement(): string
+    {
+        return '<i>$1</i>';
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/MarkdownTag.php b/src/Parsers/BBCode/Tags/MarkdownTag.php
new file mode 100644
index 00000000..035f20a3
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/MarkdownTag.php
@@ -0,0 +1,19 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\MarkdownParser;
+use Misuzu\Parsers\BBCode\BBCodeTag;
+
+final class MarkdownTag extends BBCodeTag
+{
+    public function parseText(string $text): string
+    {
+        return preg_replace_callback(
+            '#\[md\](.*?)\[/md\]#s',
+            function ($matches) {
+                return MarkdownParser::getOrCreateInstance()->parseText($matches[1]);
+            },
+            $text
+        );
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/NewLineTag.php b/src/Parsers/BBCode/Tags/NewLineTag.php
new file mode 100644
index 00000000..d83ccae1
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/NewLineTag.php
@@ -0,0 +1,17 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeSimpleTag;
+
+final class NewLineTag extends BBCodeSimpleTag
+{
+    public function getPattern(): string
+    {
+        return "/\r\n|\r|\n/";
+    }
+
+    public function getReplacement(): string
+    {
+        return '<br>';
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/QuoteTag.php b/src/Parsers/BBCode/Tags/QuoteTag.php
new file mode 100644
index 00000000..8d3903f5
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/QuoteTag.php
@@ -0,0 +1,24 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeTag;
+
+final class QuoteTag extends BBCodeTag
+{
+    public function parseText(string $text): string
+    {
+        return preg_replace_callback(
+            '#\[quote(?:=(.*))?\](.*)\[/quote\]#',
+            function ($matches) {
+                $prefix = '';
+
+                if (!empty($matches[1])) {
+                    $prefix = "<small>{$matches[1]}:</small>";
+                }
+
+                return "<blockquote>{$prefix}{$matches[2]}</blockquote>";
+            },
+            $text
+        );
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/SpoilerTag.php b/src/Parsers/BBCode/Tags/SpoilerTag.php
new file mode 100644
index 00000000..947d85d0
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/SpoilerTag.php
@@ -0,0 +1,17 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeSimpleTag;
+
+final class SpoilerTag extends BBCodeSimpleTag
+{
+    public function getPattern(): string
+    {
+        return "/\[spoiler\](.*)\[\/spoiler\]/";
+    }
+
+    public function getReplacement(): string
+    {
+        return '<span class="spoiler-class-name">$1</span>';
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/StrikeTag.php b/src/Parsers/BBCode/Tags/StrikeTag.php
new file mode 100644
index 00000000..8d59caed
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/StrikeTag.php
@@ -0,0 +1,17 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeSimpleTag;
+
+final class StrikeTag extends BBCodeSimpleTag
+{
+    public function getPattern(): string
+    {
+        return "/\[s\](.*)\[\/s\]/";
+    }
+
+    public function getReplacement(): string
+    {
+        return '<del>$1</del>';
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/UnderlineTag.php b/src/Parsers/BBCode/Tags/UnderlineTag.php
new file mode 100644
index 00000000..f56d255a
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/UnderlineTag.php
@@ -0,0 +1,17 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeSimpleTag;
+
+final class UnderlineTag extends BBCodeSimpleTag
+{
+    public function getPattern(): string
+    {
+        return "/\[u\](.*)\[\/u\]/";
+    }
+
+    public function getReplacement(): string
+    {
+        return '<u>$1</u>';
+    }
+}
diff --git a/src/Parsers/BBCode/Tags/VideoTag.php b/src/Parsers/BBCode/Tags/VideoTag.php
new file mode 100644
index 00000000..6ebf4e1c
--- /dev/null
+++ b/src/Parsers/BBCode/Tags/VideoTag.php
@@ -0,0 +1,26 @@
+<?php
+namespace Misuzu\Parsers\BBCode\Tags;
+
+use Misuzu\Parsers\BBCode\BBCodeTag;
+
+final class VideoTag extends BBCodeTag
+{
+    private const YOUTUBE_REGEX = '#^https?://(?:www\.)?youtu(?:be\.(?:[a-z]{2,63})|\.be|\be-nocookie\.com)/(?:.*?)v=([a-zA-Z0-9_-]+)#si';
+
+    public function parseText(string $text): string
+    {
+        return preg_replace_callback(
+            '#\[video\]((?:https?:\/\/).*)\[/video\]#',
+            function ($matches) {
+                if (preg_match(self::YOUTUBE_REGEX, $matches[1], $ytMatches)) {
+                    return '<iframe width="560" height="315" src="https://www.youtube-nocookie.com/embed/'
+                        . $ytMatches[1]
+                        . '?rel=0" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>';
+                }
+
+                return "<video controls src='{$matches[1]}'></video>";
+            },
+            $text
+        );
+    }
+}
diff --git a/src/Parsers/MarkdownParser.php b/src/Parsers/MarkdownParser.php
new file mode 100644
index 00000000..5ad92b6a
--- /dev/null
+++ b/src/Parsers/MarkdownParser.php
@@ -0,0 +1,20 @@
+<?php
+namespace Misuzu\Parsers;
+
+use Parsedown;
+
+final class MarkdownParser extends Parser
+{
+    private $parsedown;
+
+    public function __construct()
+    {
+        parent::__construct();
+        $this->parsedown = new Parsedown;
+    }
+
+    public function parseText(string $text): string
+    {
+        return $this->parsedown->text($text);
+    }
+}
diff --git a/src/Parsers/Parser.php b/src/Parsers/Parser.php
new file mode 100644
index 00000000..e9c19750
--- /dev/null
+++ b/src/Parsers/Parser.php
@@ -0,0 +1,34 @@
+<?php
+namespace Misuzu\Parsers;
+
+abstract class Parser
+{
+    private static $instances = [];
+
+    public function __construct()
+    {
+        self::$instances[static::class] = $this;
+    }
+
+    public static function getInstance(): ?Parser
+    {
+        if (!array_key_exists(static::class, self::$instances)) {
+            return null;
+        }
+
+        return self::$instances[static::class];
+    }
+
+    public static function getOrCreateInstance(...$args): Parser
+    {
+        $instance = static::getInstance();
+
+        if ($instance === null) {
+            $instance = new static(...$args);
+        }
+
+        return $instance;
+    }
+
+    abstract public function parseText(string $text): string;
+}
diff --git a/utility.php b/utility.php
index 9e0086d6..fd83563d 100644
--- a/utility.php
+++ b/utility.php
@@ -220,3 +220,13 @@ function pdo_prepare_array(array $keys, bool $useKeys = false, string $format =
 
     return implode(', ', $parts);
 }
+
+function parse_markdown(string $text): string
+{
+    return \Misuzu\Parsers\MarkdownParser::getOrCreateInstance()->parseText($text);
+}
+
+function parse_bbcode(string $text): string
+{
+    return \Misuzu\Parsers\BBCode\BBCodeParser::getOrCreateInstance()->parseText($text);
+}
diff --git a/views/mio/forum/macros.twig b/views/mio/forum/macros.twig
index 0736a361..041efbb6 100644
--- a/views/mio/forum/macros.twig
+++ b/views/mio/forum/macros.twig
@@ -281,7 +281,13 @@
                 </a>
             </div>
             <div class="forum__post__content__text">
-                {{ post.post_text }}
+                {% if post.post_parse == 2 %}
+                    {{ post.post_text|escape|md|raw }}
+                {% elseif post.post_parse == 1 %}
+                    {{ post.post_text|escape|bbcode|raw }}
+                {% else %}
+                    {{ post.post_text|escape }}
+                {% endif %}
             </div>
         </div>
     </div>
diff --git a/views/mio/master.twig b/views/mio/master.twig
index 0096ec72..590b2db9 100644
--- a/views/mio/master.twig
+++ b/views/mio/master.twig
@@ -97,9 +97,9 @@
                     return;
 
                 if (containerIsClosed(elem))
-                    openContainer(elem);
+                    openContainer(id);
                 else
-                    closeContainer(elem);
+                    closeContainer(id);
             }
 
             function openContainer(id) {
diff --git a/views/mio/news/post.twig b/views/mio/news/post.twig
index d7cf9ced..29e8ea6f 100644
--- a/views/mio/news/post.twig
+++ b/views/mio/news/post.twig
@@ -12,7 +12,7 @@
 
         <div class="container__content news__post__content">
             <div class="news__post__text">
-                {{ post.post_text|raw }}
+                {{ post.post_text|md|raw }}
             </div>
 
             <div class="news__sidebar news__post__details">