diff --git a/lib/mobilizon/actors/actor.ex b/lib/mobilizon/actors/actor.ex
index b264eee4a..0c9804ec2 100644
--- a/lib/mobilizon/actors/actor.ex
+++ b/lib/mobilizon/actors/actor.ex
@@ -213,7 +213,7 @@ defmodule Mobilizon.Actors.Actor do
   @doc """
   Get a public key for a given ActivityPub actor ID (url)
   """
-  @spec get_public_key_for_url(String.t()) :: {:ok, String.t()}
+  @spec get_public_key_for_url(String.t()) :: {:ok, String.t()} | {:error, atom()}
   def get_public_key_for_url(url) do
     with {:ok, %Actor{keys: keys}} <- Actors.get_or_fetch_by_url(url),
          {:ok, public_key} <- prepare_public_key(keys) do
diff --git a/lib/mobilizon/events/events.ex b/lib/mobilizon/events/events.ex
index 0e50ee4ee..6fc784991 100644
--- a/lib/mobilizon/events/events.ex
+++ b/lib/mobilizon/events/events.ex
@@ -579,6 +579,7 @@ defmodule Mobilizon.Events do
   @doc """
   Create a relation between two tags
   """
+  @spec create_tag_relation(map()) :: {:ok, TagRelation.t()} | {:error, Ecto.Changeset.t()}
   def create_tag_relation(attrs \\ {}) do
     %TagRelation{}
     |> TagRelation.changeset(attrs)
diff --git a/lib/mobilizon_web/api/groups.ex b/lib/mobilizon_web/api/groups.ex
index 96e891851..ac630b2a8 100644
--- a/lib/mobilizon_web/api/groups.ex
+++ b/lib/mobilizon_web/api/groups.ex
@@ -51,7 +51,7 @@ defmodule MobilizonWeb.API.Groups do
       {:existing_group, _} ->
         {:error, :existing_group_name}
 
-      {:bad_actor} ->
+      {:bad_actor, _} ->
         {:error, :bad_admin_actor}
     end
   end
diff --git a/lib/mobilizon_web/http_signature.ex b/lib/mobilizon_web/http_signature.ex
index a10b8c123..01aef6018 100644
--- a/lib/mobilizon_web/http_signature.ex
+++ b/lib/mobilizon_web/http_signature.ex
@@ -32,8 +32,7 @@ defmodule MobilizonWeb.HTTPSignaturePlug do
     [signature | _] = get_req_header(conn, "signature")
 
     cond do
-      # Dialyzer doesn't like this line
-      signature && String.contains?(signature, actor) ->
+      String.contains?(signature, actor) ->
         conn =
           conn
           |> put_req_header(
diff --git a/lib/service/activity_pub/activity_pub.ex b/lib/service/activity_pub/activity_pub.ex
index 015f11c70..bf6e6da0c 100644
--- a/lib/service/activity_pub/activity_pub.ex
+++ b/lib/service/activity_pub/activity_pub.ex
@@ -36,9 +36,8 @@ defmodule Mobilizon.Service.ActivityPub do
 
   @doc """
   Wraps an object into an activity
-
-  TODO: Rename me
   """
+  # TODO: Rename me
   @spec insert(map(), boolean()) :: {:ok, %Activity{}} | {:error, any()}
   def insert(map, local \\ true) when is_map(map) do
     with map <- lazy_put_activity_defaults(map),
@@ -113,6 +112,9 @@ defmodule Mobilizon.Service.ActivityPub do
     end
   end
 
+  @doc """
+  Create an activity of type "Create"
+  """
   def create(%{to: to, actor: actor, object: object} = params) do
     Logger.debug("creating an activity")
     Logger.debug(inspect(params))
@@ -240,6 +242,9 @@ defmodule Mobilizon.Service.ActivityPub do
   #   end
   # end
 
+  @doc """
+  Make an actor follow another
+  """
   def follow(%Actor{} = follower, %Actor{} = followed, activity_id \\ nil, local \\ true) do
     with {:ok, %Follower{} = follow} <- Actor.follow(followed, follower, true),
          activity_follow_id <- activity_id || Follower.url(follow),
@@ -253,6 +258,9 @@ defmodule Mobilizon.Service.ActivityPub do
     end
   end
 
+  @doc """
+  Make an actor unfollow another
+  """
   @spec unfollow(Actor.t(), Actor.t(), String.t(), boolean()) :: {:ok, map()} | any()
   def unfollow(%Actor{} = followed, %Actor{} = follower, activity_id \\ nil, local \\ true) do
     with {:ok, %Follower{id: follow_id}} <- Actor.unfollow(followed, follower),
@@ -337,7 +345,7 @@ defmodule Mobilizon.Service.ActivityPub do
   end
 
   @doc """
-  Find an actor in our local database or call Webfinger to find what's its AP ID is and then fetch it
+  Find an actor in our local database or call WebFinger to find what's its AP ID is and then fetch it
   """
   @spec find_or_make_actor_from_nickname(String.t(), atom() | nil) :: tuple()
   def find_or_make_actor_from_nickname(nickname, type \\ nil) do
@@ -355,7 +363,7 @@ defmodule Mobilizon.Service.ActivityPub do
   def find_or_make_group_from_nickname(nick), do: find_or_make_actor_from_nickname(nick, :Group)
 
   @doc """
-  Create an actor inside our database from username, using Webfinger to find out it's AP ID and then fetch it
+  Create an actor inside our database from username, using WebFinger to find out it's AP ID and then fetch it
   """
   @spec make_actor_from_nickname(String.t()) :: {:ok, %Actor{}} | {:error, any()}
   def make_actor_from_nickname(nickname) do
@@ -366,6 +374,9 @@ defmodule Mobilizon.Service.ActivityPub do
     end
   end
 
+  @doc """
+  Publish an activity to all appropriated audiences inboxes
+  """
   def publish(actor, activity) do
     Logger.debug("Publishing an activity")
 
@@ -395,6 +406,9 @@ defmodule Mobilizon.Service.ActivityPub do
     end)
   end
 
+  @doc """
+  Publish an activity to a specific inbox
+  """
   def publish_one(%{inbox: inbox, json: json, actor: actor, id: id}) do
     Logger.info("Federating #{id} to #{inbox}")
     %URI{host: host, path: path} = URI.parse(inbox)
@@ -425,7 +439,7 @@ defmodule Mobilizon.Service.ActivityPub do
     )
   end
 
-  # Fetching a remote actor's informations through it's AP ID
+  # Fetching a remote actor's information through it's AP ID
   @spec fetch_and_prepare_actor_from_url(String.t()) :: {:ok, struct()} | {:error, atom()} | any()
   defp fetch_and_prepare_actor_from_url(url) do
     Logger.debug("Fetching and preparing actor from url")
@@ -447,6 +461,9 @@ defmodule Mobilizon.Service.ActivityPub do
 
   @doc """
   Creating proper actor data struct from AP data
+
+
+  Convert ActivityPub data to our internal format
   """
   @spec actor_data_from_actor_object(map()) :: {:ok, map()}
   def actor_data_from_actor_object(data) when is_map(data) do
@@ -533,7 +550,7 @@ defmodule Mobilizon.Service.ActivityPub do
 
   # Create an activity from a comment
   @spec comment_to_activity(%Comment{}, boolean()) :: Activity.t()
-  def comment_to_activity(%Comment{} = comment, local \\ true) do
+  defp comment_to_activity(%Comment{} = comment, local \\ true) do
     %Activity{
       recipients: ["https://www.w3.org/ns/activitystreams#Public"],
       actor: comment.actor.url,
@@ -590,8 +607,9 @@ defmodule Mobilizon.Service.ActivityPub do
     nil
   end
 
-  def is_public?(activity) do
-    "https://www.w3.org/ns/activitystreams#Public" in (activity.data["to"] ++
-                                                         (activity.data["cc"] || []))
-  end
+  #  # Whether the Public audience is in the activity's audience
+  #  defp is_public?(activity) do
+  #    "https://www.w3.org/ns/activitystreams#Public" in (activity.data["to"] ++
+  #                                                         (activity.data["cc"] || []))
+  #  end
 end
diff --git a/lib/service/activity_pub/transmogrifier.ex b/lib/service/activity_pub/transmogrifier.ex
index 965446348..d11d60613 100644
--- a/lib/service/activity_pub/transmogrifier.ex
+++ b/lib/service/activity_pub/transmogrifier.ex
@@ -498,8 +498,10 @@ defmodule Mobilizon.Service.ActivityPub.Transmogrifier do
 
   @spec normalize(map()) :: struct() | nil
   def normalize(obj) when is_map(obj), do: get_anything_by_url(obj["id"])
+
   @spec normalize(String.t()) :: struct() | nil
   def normalize(url) when is_binary(url), do: get_anything_by_url(url)
+
   @spec normalize(any()) :: nil
   def normalize(_), do: nil
 
diff --git a/lib/service/activity_pub/utils.ex b/lib/service/activity_pub/utils.ex
index 0c243054f..637b1c132 100644
--- a/lib/service/activity_pub/utils.ex
+++ b/lib/service/activity_pub/utils.ex
@@ -188,7 +188,7 @@ defmodule Mobilizon.Service.ActivityPub.Utils do
               |> Map.put("in_reply_to_comment_id", id)
               |> Map.put("origin_comment_id", comment |> Comment.get_thread_id())
 
-            # Anthing else is kind of a MP
+            # Anything else is kind of a MP
             {:error, object} ->
               Logger.debug("Parent object is something we don't handle")
               Logger.debug(inspect(object))
@@ -239,6 +239,16 @@ defmodule Mobilizon.Service.ActivityPub.Utils do
   @doc """
   Make an AP event object from an set of values
   """
+  @spec make_event_data(
+          String.t(),
+          String.t(),
+          String.t(),
+          String.t(),
+          list(),
+          list(),
+          map(),
+          String.t()
+        ) :: map()
   def make_event_data(
         actor,
         to,
@@ -271,6 +281,7 @@ defmodule Mobilizon.Service.ActivityPub.Utils do
     }
   end
 
+  @spec make_event_data(Event.t(), list(String.t())) :: map()
   def make_event_data(
         %Event{title: title, organizer_actor: actor, uuid: uuid},
         to \\ ["https://www.w3.org/ns/activitystreams#Public"]
diff --git a/lib/service/web_finger/web_finger.ex b/lib/service/web_finger/web_finger.ex
index 4e453bf59..5e765efd6 100644
--- a/lib/service/web_finger/web_finger.ex
+++ b/lib/service/web_finger/web_finger.ex
@@ -55,6 +55,7 @@ defmodule Mobilizon.Service.WebFinger do
   @spec represent_actor(Actor.t()) :: struct()
   def represent_actor(actor), do: represent_actor(actor, "JSON")
 
+  @spec represent_actor(Actor.t(), String.t()) :: struct()
   def represent_actor(actor, "JSON") do
     %{
       "subject" => "acct:#{actor.preferred_username}@#{MobilizonWeb.Endpoint.host()}",