diff --git a/app/helpers/formatting_helper.rb b/app/helpers/formatting_helper.rb
index 7d1423e52d..a71ff32e1e 100644
--- a/app/helpers/formatting_helper.rb
+++ b/app/helpers/formatting_helper.rb
@@ -19,7 +19,7 @@ module FormattingHelper
   module_function :extract_status_plain_text

   def status_content_format(status)
-    html_aware_format(status.text, status.local?, preloaded_accounts: [status.account] + (status.respond_to?(:active_mentions) ? status.active_mentions.map(&:account) : []))
+    html_aware_format(status.text, status.local?, preloaded_accounts: [status.account] + (status.respond_to?(:active_mentions) ? status.active_mentions.map(&:account) : []), content_type: 'text/markdown')
   end

   def rss_status_content_format(status)
diff --git a/app/lib/advanced_text_formatter.rb b/app/lib/advanced_text_formatter.rb
new file mode 100644
index 0000000000..21e81d4d1e
--- /dev/null
+++ b/app/lib/advanced_text_formatter.rb
@@ -0,0 +1,133 @@
+# frozen_string_literal: true
+
+class AdvancedTextFormatter < TextFormatter
+  class HTMLRenderer < Redcarpet::Render::HTML
+    def initialize(options, &block)
+      super(options)
+      @format_link = block
+    end
+
+    def block_code(code, _language)
+      <<~HTML
+        <pre><code>#{ERB::Util.h(code).gsub("\n", '<br/>')}</code></pre>
+      HTML
+    end
+
+    def autolink(link, link_type)
+      return link if link_type == :email
+      @format_link.call(link)
+    end
+  end
+
+  attr_reader :content_type
+
+  # @param [String] text
+  # @param [Hash] options
+  # @option options [Boolean] :multiline
+  # @option options [Boolean] :with_domains
+  # @option options [Boolean] :with_rel_me
+  # @option options [Array<Account>] :preloaded_accounts
+  # @option options [String] :content_type
+  def initialize(text, options = {})
+    @content_type = options.delete(:content_type)
+    super(text, options)
+
+    @text = format_markdown(text) if content_type == 'text/markdown'
+  end
+
+  # Differs from TextFormatter by not messing with newline after parsing
+  def to_s
+    return ''.html_safe if text.blank?
+
+    html = rewrite do |entity|
+      if entity[:url]
+        link_to_url(entity)
+      elsif entity[:hashtag]
+        link_to_hashtag(entity)
+      elsif entity[:screen_name]
+        link_to_mention(entity)
+      end
+    end
+
+    html.html_safe # rubocop:disable Rails/OutputSafety
+  end
+
+  # Differs from TextFormatter by operating on the parsed HTML tree
+  def rewrite
+    if @tree.nil?
+      src = text.gsub(Sanitize::REGEX_UNSUITABLE_CHARS, '')
+      @tree = Nokogiri::HTML5.fragment(src)
+      document = @tree.document
+
+      @tree.xpath('.//text()[not(ancestor::a | ancestor::code)]').each do |text_node|
+        # Iterate over text elements and build up their replacements.
+        content = text_node.content
+        replacement = Nokogiri::XML::NodeSet.new(document)
+        processed_index = 0
+        Extractor.extract_entities_with_indices(
+          content,
+          extract_url_without_protocol: false
+        ) do |entity|
+          # Iterate over entities in this text node.
+          advance = entity[:indices].first - processed_index
+          if advance.positive?
+            # Text node for content which precedes entity.
+            replacement << Nokogiri::XML::Text.new(
+              content[processed_index, advance],
+              document
+            )
+          end
+          replacement << Nokogiri::HTML5.fragment(yield(entity))
+          processed_index = entity[:indices].last
+        end
+        if processed_index < content.size
+          # Text node for remaining content.
+          replacement << Nokogiri::XML::Text.new(
+            content[processed_index, content.size - processed_index],
+            document
+          )
+        end
+        text_node.replace(replacement)
+      end
+    end
+
+    Sanitize.node!(@tree, Sanitize::Config::MASTODON_OUTGOING).to_html
+  end
+
+  private
+
+  def format_markdown(html)
+    html = markdown_formatter.render(html)
+    html.delete("\r").delete("\n")
+  end
+
+  def markdown_formatter
+    extensions = {
+      autolink: true,
+      no_intra_emphasis: true,
+      fenced_code_blocks: true,
+      disable_indented_code_blocks: true,
+      strikethrough: true,
+      lax_spacing: true,
+      space_after_headers: true,
+      superscript: true,
+      underline: true,
+      highlight: true,
+      footnotes: false,
+    }
+
+    renderer = HTMLRenderer.new({
+      filter_html: false,
+      escape_html: false,
+      no_images: true,
+      no_styles: true,
+      safe_links_only: true,
+      hard_wrap: true,
+      link_attributes: { target: '_blank', rel: 'nofollow noopener' },
+    }) do |url|
+      link_to_url({ url: url })
+    end
+
+    Redcarpet::Markdown.new(renderer, extensions)
+  end
+end
diff --git a/app/lib/html_aware_formatter.rb b/app/lib/html_aware_formatter.rb
index 64edba09b5..7a1cd03409 100644
--- a/app/lib/html_aware_formatter.rb
+++ b/app/lib/html_aware_formatter.rb
@@ -33,6 +33,10 @@ class HtmlAwareFormatter
   end

   def linkify
-    TextFormatter.new(text, options).to_s
+    if %w(text/markdown text/html).include?(@options[:content_type])
+      AdvancedTextFormatter.new(text, options).to_s
+    else
+      TextFormatter.new(text, options).to_s
+    end
   end
 end
diff --git a/lib/sanitize_ext/sanitize_config.rb b/lib/sanitize_ext/sanitize_config.rb
index f0a7b65783..7fe667db54 100644
--- a/lib/sanitize_ext/sanitize_config.rb
+++ b/lib/sanitize_ext/sanitize_config.rb
@@ -112,5 +112,47 @@ class Sanitize
         'iframe' => { 'sandbox' => 'allow-scripts allow-same-origin allow-popups allow-popups-to-escape-sandbox allow-forms' },
       }
     )
+
+    LINK_REL_TRANSFORMER = lambda do |env|
+      return unless env[:node_name] == 'a' && env[:node]['href']
+
+      node = env[:node]
+
+      rel = (node['rel'] || '').split(' ') & ['tag']
+      rel += ['nofollow', 'noopener', 'noreferrer'] unless TagManager.instance.local_url?(node['href'])
+
+      if rel.empty?
+        node.remove_attribute('rel')
+      else
+        node['rel'] = rel.join(' ')
+      end
+    end
+
+    LINK_TARGET_TRANSFORMER = lambda do |env|
+      return unless env[:node_name] == 'a' && env[:node]['href']
+
+      node = env[:node]
+      if node['target'] != '_blank' && TagManager.instance.local_url?(node['href'])
+        node.remove_attribute('target')
+      else
+        node['target'] = '_blank'
+      end
+    end
+
+    MASTODON_OUTGOING ||= freeze_config MASTODON_STRICT.merge(
+      attributes: merge(
+        MASTODON_STRICT[:attributes],
+        'a' => %w(href rel class title target)
+      ),
+
+      add_attributes: {},
+
+      transformers: [
+        CLASS_WHITELIST_TRANSFORMER,
+        UNSUPPORTED_HREF_TRANSFORMER,
+        LINK_REL_TRANSFORMER,
+        LINK_TARGET_TRANSFORMER,
+      ]
+    )
   end
 end
diff --git a/spec/lib/advanced_text_formatter_spec.rb b/spec/lib/advanced_text_formatter_spec.rb
new file mode 100644
index 0000000000..c1e4696061
--- /dev/null
+++ b/spec/lib/advanced_text_formatter_spec.rb
@@ -0,0 +1,298 @@
+require 'rails_helper'
+
+RSpec.describe AdvancedTextFormatter do
+  describe '#to_s' do
+    let(:preloaded_accounts) { nil }
+    let(:content_type) { 'text/markdown' }
+
+    subject { described_class.new(text, preloaded_accounts: preloaded_accounts, content_type: content_type).to_s }
+
+    context 'given a markdown source' do
+      let(:content_type) { 'text/markdown' }
+
+      context 'given text containing plain text' do
+        let(:text) { 'text' }
+
+        it 'paragraphizes the text' do
+          is_expected.to eq '<p>text</p>'
+        end
+      end
+
+      context 'given text containing line feeds' do
+        let(:text) { "line\nfeed" }
+
+        it 'removes line feeds' do
+          is_expected.not_to include "\n"
+        end
+      end
+
+      context 'given some inline code using backticks' do
+        let(:text) { 'test `foo` bar' }
+
+        it 'formats code using <code>' do
+          is_expected.to include 'test <code>foo</code> bar'
+        end
+      end
+
+      context 'given a block code' do
+        let(:text) { "test\n\n```\nint main(void) {\n  return 0; // https://joinmastodon.org/foo\n}\n```\n" }
+
+        it 'formats code using <pre> and <code>' do
+          is_expected.to include '<pre><code>int main'
+        end
+
+        it 'does not strip leading spaces' do
+          is_expected.to include '>  return 0'
+        end
+
+        it 'does not format links' do
+          is_expected.to include 'return 0; // https://joinmastodon.org/foo'
+        end
+      end
+
+      context 'given a link in inline code using backticks' do
+        let(:text) { 'test `https://foo.bar/bar` bar' }
+
+        it 'does not rewrite the link' do
+          is_expected.to include 'test <code>https://foo.bar/bar</code> bar'
+        end
+      end
+
+      context 'given text with a local-domain mention' do
+        let(:text) { 'foo https://cb6e6126.ngrok.io/about/more' }
+
+        it 'creates a link' do
+          is_expected.to include '<a href="https://cb6e6126.ngrok.io/about/more"'
+        end
+      end
+
+      context 'given text containing linkable mentions' do
+        let(:preloaded_accounts) { [Fabricate(:account, username: 'alice')] }
+        let(:text) { '@alice' }
+
+        it 'creates a mention link' do
+          is_expected.to include '<a href="https://cb6e6126.ngrok.io/@alice" class="u-url mention">@<span>alice</span></a></span>'
+        end
+      end
+
+      context 'given text containing unlinkable mentions' do
+        let(:preloaded_accounts) { [] }
+        let(:text) { '@alice' }
+
+        it 'does not create a mention link' do
+          is_expected.to include '@alice'
+        end
+      end
+
+      context 'given a stand-alone medium URL' do
+        let(:text) { 'https://hackernoon.com/the-power-to-build-communities-a-response-to-mark-zuckerberg-3f2cac9148a4' }
+
+        it 'matches the full URL' do
+          is_expected.to include 'href="https://hackernoon.com/the-power-to-build-communities-a-response-to-mark-zuckerberg-3f2cac9148a4"'
+        end
+      end
+
+      context 'given a stand-alone google URL' do
+        let(:text) { 'http://google.com' }
+
+        it 'matches the full URL' do
+          is_expected.to include 'href="http://google.com"'
+        end
+      end
+
+      context 'given a stand-alone URL with a newer TLD' do
+        let(:text) { 'http://example.gay' }
+
+        it 'matches the full URL' do
+          is_expected.to include 'href="http://example.gay"'
+        end
+      end
+
+      context 'given a stand-alone IDN URL' do
+        let(:text) { 'https://nic.みんな/' }
+
+        it 'matches the full URL' do
+          is_expected.to include 'href="https://nic.みんな/"'
+        end
+
+        it 'has display URL' do
+          is_expected.to include '<span class="">nic.みんな/</span>'
+        end
+      end
+
+      context 'given a URL with a trailing period' do
+        let(:text) { 'http://www.mcmansionhell.com/post/156408871451/50-states-of-mcmansion-hell-scottsdale-arizona. ' }
+
+        it 'matches the full URL but not the period' do
+          is_expected.to include 'href="http://www.mcmansionhell.com/post/156408871451/50-states-of-mcmansion-hell-scottsdale-arizona"'
+        end
+      end
+
+      context 'given a URL enclosed with parentheses' do
+        let(:text) { '(http://google.com/)' }
+
+        it 'matches the full URL but not the parentheses' do
+          is_expected.to include 'href="http://google.com/"'
+        end
+      end
+
+      context 'given a URL with a trailing exclamation point' do
+        let(:text) { 'http://www.google.com!' }
+
+        it 'matches the full URL but not the exclamation point' do
+          is_expected.to include 'href="http://www.google.com"'
+        end
+      end
+
+      context 'given a URL with a trailing single quote' do
+        let(:text) { "http://www.google.com'" }
+
+        it 'matches the full URL but not the single quote' do
+          is_expected.to include 'href="http://www.google.com"'
+        end
+      end
+    end
+
+    context 'given a URL with a trailing angle bracket' do
+      let(:text) { 'http://www.google.com>' }
+
+      it 'matches the full URL but not the angle bracket' do
+        is_expected.to include 'href="http://www.google.com"'
+      end
+    end
+
+    context 'given a URL with a query string' do
+      context 'with escaped unicode character' do
+        let(:text) { 'https://www.ruby-toolbox.com/search?utf8=%E2%9C%93&q=autolink' }
+
+        it 'matches the full URL' do
+          is_expected.to include 'href="https://www.ruby-toolbox.com/search?utf8=%E2%9C%93&amp;q=autolink"'
+        end
+      end
+
+      context 'with unicode character' do
+        let(:text) { 'https://www.ruby-toolbox.com/search?utf8=✓&q=autolink' }
+
+        it 'matches the full URL' do
+          is_expected.to include 'href="https://www.ruby-toolbox.com/search?utf8=✓&amp;q=autolink"'
+        end
+      end
+
+      context 'with unicode character at the end' do
+        let(:text) { 'https://www.ruby-toolbox.com/search?utf8=✓' }
+
+        it 'matches the full URL' do
+          is_expected.to include 'href="https://www.ruby-toolbox.com/search?utf8=✓"'
+        end
+      end
+
+      context 'with escaped and not escaped unicode characters' do
+        let(:text) { 'https://www.ruby-toolbox.com/search?utf8=%E2%9C%93&utf81=✓&q=autolink' }
+
+        it 'preserves escaped unicode characters' do
+          is_expected.to include 'href="https://www.ruby-toolbox.com/search?utf8=%E2%9C%93&amp;utf81=✓&amp;q=autolink"'
+        end
+      end
+
+      context 'given a URL with parentheses in it' do
+        let(:text) { 'https://en.wikipedia.org/wiki/Diaspora_(software)' }
+
+        it 'matches the full URL' do
+          is_expected.to include 'href="https://en.wikipedia.org/wiki/Diaspora_(software)"'
+        end
+      end
+
+      context 'given a URL in quotation marks' do
+        let(:text) { '"https://example.com/"' }
+
+        it 'does not match the quotation marks' do
+          is_expected.to include 'href="https://example.com/"'
+        end
+      end
+
+      context 'given a URL in angle brackets' do
+        let(:text) { '<https://example.com/>' }
+
+        it 'does not match the angle brackets' do
+          is_expected.to include 'href="https://example.com/"'
+        end
+      end
+
+      context 'given a URL containing unsafe code (XSS attack, invisible part)' do
+        let(:text) { %q{http://example.com/blahblahblahblah/a<script>alert("Hello")</script>} }
+
+        it 'does not include the HTML in the URL' do
+          is_expected.to include '"http://example.com/blahblahblahblah/a"'
+        end
+
+        it 'does not include a script tag' do
+          is_expected.to_not include '<script>'
+        end
+      end
+
+      context 'given text containing HTML code (script tag)' do
+        let(:text) { '<script>alert("Hello")</script>' }
+
+        it 'does not include a script tag' do
+          is_expected.to_not include '<script>'
+        end
+      end
+
+      context 'given text containing HTML (XSS attack)' do
+        let(:text) { %q{<img src="javascript:alert('XSS');">} }
+
+        it 'does not include the javascript' do
+          is_expected.to_not include 'href="javascript:'
+        end
+      end
+
+      context 'given an invalid URL' do
+        let(:text) { 'http://www\.google\.com' }
+
+        it 'outputs the raw URL' do
+          is_expected.to eq '<p>http://www\.google\.com</p>'
+        end
+      end
+
+      context 'given text containing a hashtag' do
+        let(:text)  { '#hashtag' }
+
+        it 'creates a hashtag link' do
+          is_expected.to include '/tags/hashtag" class="mention hashtag" rel="tag">#<span>hashtag</span></a>'
+        end
+      end
+
+      context 'given text containing a hashtag with Unicode chars' do
+        let(:text)  { '#hashtagタグ' }
+
+        it 'creates a hashtag link' do
+          is_expected.to include '/tags/hashtag%E3%82%BF%E3%82%B0" class="mention hashtag" rel="tag">#<span>hashtagタグ</span></a>'
+        end
+      end
+
+      context 'given text with a stand-alone xmpp: URI' do
+        let(:text) { 'xmpp:[email protected]' }
+
+        it 'matches the full URI' do
+          is_expected.to include 'href="xmpp:[email protected]"'
+        end
+      end
+
+      context 'given text with an xmpp: URI with a query-string' do
+        let(:text) { 'please join xmpp:[email protected]?join right now' }
+
+        it 'matches the full URI' do
+          is_expected.to include 'href="xmpp:[email protected]?join"'
+        end
+      end
+
+      context 'given text containing a magnet: URI' do
+        let(:text) { 'wikipedia gives this example of a magnet uri: magnet:?xt=urn:btih:c12fe1c06bba254a9dc9f519b335aa7c1367a88a' }
+
+        it 'matches the full URI' do
+          is_expected.to include 'href="magnet:?xt=urn:btih:c12fe1c06bba254a9dc9f519b335aa7c1367a88a"'
+        end
+      end
+    end
+  end
+end