diff --git a/lib/graphql/resolvers/invitation.ex b/lib/graphql/resolvers/invitation.ex
index 1a473d3d6..ba293c154 100644
--- a/lib/graphql/resolvers/invitation.ex
+++ b/lib/graphql/resolvers/invitation.ex
@@ -5,6 +5,7 @@ defmodule Mobilizon.GraphQL.Resolvers.Invitation do
 
   alias Mobilizon.Actors
   alias Mobilizon.Actors.Actor
+  alias Mobilizon.Invitation
   alias Mobilizon.Invitations
   import Mobilizon.Web.Gettext
 
@@ -54,4 +55,33 @@ defmodule Mobilizon.GraphQL.Resolvers.Invitation do
       Invitations.delete_invitation_by_token(group_id, token)
     end
   end
+
+  def accept_invitation_token(
+        _parent,
+        %{group_id: group_id, token: token, actor_id: actor_id_chosen},
+        %{
+          context: %{current_actor: %Actor{id: actor_id_connected}}
+        }
+      ) do
+    with true <-
+           String.to_integer(actor_id_chosen) == actor_id_connected ||
+             {:error, "You can only accept invitations for your own account"},
+         %Invitation{} = _invitation <-
+           Invitations.find_invitation(group_id, token) ||
+             {:error, "Invalid invitation token for this group"},
+         false <-
+           Mobilizon.Actors.member?(actor_id_connected, group_id),
+         {:ok, member} <-
+           Mobilizon.Actors.create_member(%{
+             role: :member,
+             parent_id: group_id,
+             actor_id: actor_id_connected
+           }) do
+      {:ok, member}
+    else
+      {:error, _} = error -> error
+      true -> {:error, "You are already a member of this group"}
+      _ -> {:error, "Unexpected error"}
+    end
+  end
 end
diff --git a/lib/graphql/schema/invitation.ex b/lib/graphql/schema/invitation.ex
index bc8fbf74b..30e2d7b76 100644
--- a/lib/graphql/schema/invitation.ex
+++ b/lib/graphql/schema/invitation.ex
@@ -24,7 +24,7 @@ defmodule Mobilizon.GraphQL.Schema.InvitationType do
     @desc "Update an invitation for a group"
     field :update_invitation, type: :invitation do
       arg(:group_id, non_null(:id), description: "ID of the group")
-      arg(:token, :string, description: "Token")
+      arg(:token, non_null(:string), description: "Token")
       arg(:label, :string, description: "Label")
       middleware(Rajska.QueryAuthorization, permit: :user, scope: false)
       resolve(&Invitation.update_invitation/3)
@@ -33,10 +33,19 @@ defmodule Mobilizon.GraphQL.Schema.InvitationType do
     @desc "Delete an invitation for a group"
     field :delete_invitation, type: :invitation do
       arg(:group_id, non_null(:id), description: "ID of the group")
-      arg(:token, :string, description: "Token")
+      arg(:token, non_null(:string), description: "Token")
       middleware(Rajska.QueryAuthorization, permit: :user, scope: false)
       resolve(&Invitation.delete_invitation/3)
     end
+
+    @desc "Accept an invitation to join a group"
+    field :accept_invitation_token, type: :member do
+      arg(:actor_id, non_null(:id), description: "The ID of the actor that will join the group")
+      arg(:group_id, non_null(:id), description: "ID of the group")
+      arg(:token, :string, description: "Token")
+      middleware(Rajska.QueryAuthorization, permit: :user, scope: false)
+      resolve(&Invitation.accept_invitation_token/3)
+    end
   end
 
   object :invitation_queries do
diff --git a/lib/mobilizon/invitations/invitations.ex b/lib/mobilizon/invitations/invitations.ex
index 1b38ff6f3..e0b677034 100644
--- a/lib/mobilizon/invitations/invitations.ex
+++ b/lib/mobilizon/invitations/invitations.ex
@@ -39,4 +39,8 @@ defmodule Mobilizon.Invitations do
     |> where([i], i.group_id == ^group_id)
     |> Repo.all()
   end
+
+  def find_invitation(group_id, token) do
+    Repo.get_by(Invitation, group_id: group_id, token: token)
+  end
 end