diff --git a/lib/pleroma/web/activity_pub/object_validator.ex b/lib/pleroma/web/activity_pub/object_validator.ex
index 24f340539..5edae934b 100644
--- a/lib/pleroma/web/activity_pub/object_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validator.ex
@@ -43,9 +43,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidator do
   end
 
   def stringify_keys(object) do
-    object
-    |> Enum.map(fn {key, val} -> {to_string(key), val} end)
-    |> Enum.into(%{})
+    Map.new(object, fn {key, val} -> {to_string(key), val} end)
   end
 
   def fetch_actor_and_object(object) do
diff --git a/lib/pleroma/web/activity_pub/object_validators/like_validator.ex b/lib/pleroma/web/activity_pub/object_validators/like_validator.ex
index ccbc7d071..981996d49 100644
--- a/lib/pleroma/web/activity_pub/object_validators/like_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/like_validator.ex
@@ -30,8 +30,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.LikeValidator do
   end
 
   def cast_data(data) do
-    %__MODULE__{}
-    |> cast(data, [:id, :type, :object, :actor, :context, :to, :cc])
+    cast(%__MODULE__{}, data, [:id, :type, :object, :actor, :context, :to, :cc])
   end
 
   def validate_data(data_cng) do
diff --git a/lib/pleroma/web/activity_pub/object_validators/note_validator.ex b/lib/pleroma/web/activity_pub/object_validators/note_validator.ex
index 279d2d065..4c433ceb8 100644
--- a/lib/pleroma/web/activity_pub/object_validators/note_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/note_validator.ex
@@ -27,11 +27,9 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.NoteValidator do
     field(:attributedTo, Types.ObjectID)
     field(:summary, :string)
     field(:published, Types.DateTime)
-    # TODO: Write type
-    field(:emoji, :map, default: %{})
+    field(:emoji, Types.Emoji, default: %{})
     field(:sensitive, :boolean, default: false)
-    # TODO: Write type
-    field(:attachment, {:array, :map}, default: [])
+    field(:attachment, Types.Attachments, default: [])
     field(:replies_count, :integer, default: 0)
     field(:like_count, :integer, default: 0)
     field(:announcement_count, :integer, default: 0)
diff --git a/lib/pleroma/web/activity_pub/object_validators/types/attachments.ex b/lib/pleroma/web/activity_pub/object_validators/types/attachments.ex
new file mode 100644
index 000000000..40c930011
--- /dev/null
+++ b/lib/pleroma/web/activity_pub/object_validators/types/attachments.ex
@@ -0,0 +1,47 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.ObjectValidators.Types.Attachments do
+  use Ecto.Type
+
+  def type, do: {:array, :map}
+
+  # Note based on Transmogrifier.prepare_attachments/1
+  def cast(attachments_list) when is_list(attachments_list) do
+    if Enum.all?(attachments_list, &is_map/1) do
+      casted_attachments =
+        Enum.map(
+          attachments_list,
+          fn data ->
+            {media_type, href} =
+              with [%{"mediaType" => media_type, "href" => href} | _] <- data["url"] do
+                {media_type, href}
+              else
+                _ -> {nil, data["url"]}
+              end
+
+            %{"mediaType" => media_type, "type" => "Document"}
+            |> Map.merge(data)
+            |> Map.put("url", href)
+          end
+        )
+
+      {:ok, casted_attachments}
+    else
+      :error
+    end
+  end
+
+  def cast(_) do
+    :error
+  end
+
+  def dump(data) do
+    {:ok, data}
+  end
+
+  def load(data) do
+    {:ok, data}
+  end
+end
diff --git a/lib/pleroma/web/activity_pub/object_validators/types/emoji.ex b/lib/pleroma/web/activity_pub/object_validators/types/emoji.ex
new file mode 100644
index 000000000..f3e114fc3
--- /dev/null
+++ b/lib/pleroma/web/activity_pub/object_validators/types/emoji.ex
@@ -0,0 +1,27 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.ObjectValidators.Types.Emoji do
+  use Ecto.Type
+
+  def type, do: :map
+
+  @doc "Casts to %{name => url} format"
+  def cast(emoji) when is_map(emoji) do
+    # To do: validate that all values are URIs?
+    {:ok, emoji}
+  end
+
+  def cast(_) do
+    :error
+  end
+
+  def dump(data) do
+    {:ok, data}
+  end
+
+  def load(data) do
+    {:ok, data}
+  end
+end
diff --git a/lib/pleroma/web/activity_pub/object_validators/types/tags.ex b/lib/pleroma/web/activity_pub/object_validators/types/tags.ex
index b46743bf3..3d4158b2f 100644
--- a/lib/pleroma/web/activity_pub/object_validators/types/tags.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/types/tags.ex
@@ -3,14 +3,15 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 
 defmodule Pleroma.Web.ActivityPub.ObjectValidators.Types.Tags do
+  alias Pleroma.Web.ActivityPub.Transmogrifier
+
   use Ecto.Type
 
   def type, do: {:array, :map}
 
-  # Note: supporting binaries and maps as list elements
-  def cast(list) when is_list(list) do
-    if Enum.all?(list, &(is_map(&1) || is_binary(&1))) do
-      {:ok, list}
+  def cast(tags_list) when is_list(tags_list) do
+    if Enum.all?(tags_list, &(is_map(&1) || is_binary(&1))) do
+      {:ok, Transmogrifier.as2_tags(tags_list)}
     else
       :error
     end
diff --git a/lib/pleroma/web/activity_pub/transmogrifier.ex b/lib/pleroma/web/activity_pub/transmogrifier.ex
index ba12d9853..ac070e895 100644
--- a/lib/pleroma/web/activity_pub/transmogrifier.ex
+++ b/lib/pleroma/web/activity_pub/transmogrifier.ex
@@ -31,17 +31,17 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   """
   def fix_object(object, options \\ []) do
     object
-    |> strip_internal_fields
-    |> fix_actor
-    |> fix_url
-    |> fix_attachments
-    |> fix_context
+    |> strip_internal_fields()
+    |> fix_actor()
+    |> fix_url()
+    |> fix_attachments()
+    |> fix_context()
     |> fix_in_reply_to(options)
-    |> fix_emoji
-    |> fix_tag
-    |> fix_content_map
-    |> fix_addressing
-    |> fix_summary
+    |> fix_emoji()
+    |> fix_tag()
+    |> fix_content_map()
+    |> fix_addressing()
+    |> fix_summary()
     |> fix_type(options)
   end
 
@@ -931,17 +931,17 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   # Prepares the object of an outgoing create activity.
   def prepare_object(object) do
     object
-    |> set_sensitive
-    |> add_hashtags
-    |> add_mention_tags
-    |> add_emoji_tags
-    |> add_attributed_to
-    |> prepare_attachments
-    |> set_conversation
-    |> set_reply_to_uri
-    |> strip_internal_fields
-    |> strip_internal_tags
-    |> set_type
+    |> set_sensitive()
+    |> add_hashtags()
+    |> add_mention_tags()
+    |> add_emoji_tags()
+    |> add_attributed_to()
+    |> prepare_attachments()
+    |> set_conversation()
+    |> set_reply_to_uri()
+    |> strip_internal_fields()
+    |> strip_internal_tags()
+    |> set_type()
   end
 
   #  @doc
@@ -955,7 +955,7 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
       object_id
       |> Object.normalize()
       |> Map.get(:data)
-      |> prepare_object
+      |> prepare_object()
 
     data =
       data
@@ -975,12 +975,12 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
       if Visibility.is_private?(object) && object.data["actor"] == ap_id do
         data |> Map.put("object", object |> Map.get(:data) |> prepare_object)
       else
-        data |> maybe_fix_object_url
+        maybe_fix_object_url(data)
       end
 
     data =
       data
-      |> strip_internal_fields
+      |> strip_internal_fields()
       |> Map.merge(Utils.make_json_ld_header())
       |> Map.delete("bcc")
 
@@ -1028,8 +1028,8 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   def prepare_outgoing(%{"type" => _type} = data) do
     data =
       data
-      |> strip_internal_fields
-      |> maybe_fix_object_url
+      |> strip_internal_fields()
+      |> maybe_fix_object_url()
       |> Map.merge(Utils.make_json_ld_header())
 
     {:ok, data}
@@ -1054,9 +1054,15 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   def maybe_fix_object_url(data), do: data
 
   def add_hashtags(object) do
-    tags =
-      (object["tag"] || [])
-      |> Enum.map(fn
+    tags = as2_tags(object["tag"] || [])
+    Map.put(object, "tag", tags)
+  end
+
+  @doc "Converts `tag` list to ActivityStreams 2.0 format"
+  def as2_tags(tags) when is_list(tags) do
+    Enum.map(
+      tags,
+      fn
         # Expand internal representation tags into AS2 tags.
         tag when is_binary(tag) ->
           %{
@@ -1068,9 +1074,8 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
         # Do not process tags which are already AS2 tag objects.
         tag when is_map(tag) ->
           tag
-      end)
-
-    Map.put(object, "tag", tags)
+      end
+    )
   end
 
   def add_mention_tags(object) do