diff --git a/lib/cgrates_web_jsonapi/cdrs.ex b/lib/cgrates_web_jsonapi/cdrs.ex
index aae7df6..d5f7d85 100644
--- a/lib/cgrates_web_jsonapi/cdrs.ex
+++ b/lib/cgrates_web_jsonapi/cdrs.ex
@@ -58,6 +58,16 @@ defmodule CgratesWebJsonapi.Cdrs do
     |> Enum.map(&CdrsStats.new/1)
   end
 
+  def extra do
+    request = "SELECT DISTINCT extra_fields
+        FROM (
+          SELECT jsonb_object_keys(extra_fields) AS extra_fields
+          FROM cdrs
+        ) AS subquery"
+
+    request |> Repo.query() |> elem(1) |> Map.get(:rows) |> List.flatten()
+  end
+
   defp group_by_created_at(q, :daily) do
     q |> group_by([r], fragment("date_trunc('day', ?)", r.created_at))
   end
diff --git a/lib/cgrates_web_jsonapi/ets_cache.ex b/lib/cgrates_web_jsonapi/ets_cache.ex
new file mode 100644
index 0000000..6100b7e
--- /dev/null
+++ b/lib/cgrates_web_jsonapi/ets_cache.ex
@@ -0,0 +1,46 @@
+defmodule CgratesWebJsonapi.EtsCache do
+  @moduledoc """
+  Cache via ETS.
+  """
+
+  @spec get(any, atom | :ets.tid(), any) :: list(any)
+  def get(args, table_name, opts \\ []) do
+    case lookup(args, table_name) do
+      nil ->
+        ttl = Keyword.get(opts, :ttl, 86400)
+        cache_apply(args.(), ttl)
+
+      result ->
+        result
+    end
+  end
+
+  defp lookup(args, table_name) do
+    maybe_create_table(table_name)
+
+    case :ets.lookup(table_name, [args]) do
+      [result | _] -> check_freshness(result)
+      [] -> nil
+    end
+  end
+
+  defp check_freshness({result, expiration}) do
+    cond do
+      expiration > :os.system_time(:seconds) -> result
+      :else -> nil
+    end
+  end
+
+  defp cache_apply(args, ttl) do
+    result = args
+    expiration = :os.system_time(:seconds) + ttl
+    :ets.insert(:extra_fields, {args, result, expiration})
+    result
+  end
+
+  defp maybe_create_table(table_name) do
+    if Enum.member?(:ets.all(), table_name) == false do
+      :ets.new(table_name, [:public, :named_table])
+    end
+  end
+end
diff --git a/lib/cgrates_web_jsonapi/tenants.ex b/lib/cgrates_web_jsonapi/tenants.ex
index 811d472..84d2d33 100644
--- a/lib/cgrates_web_jsonapi/tenants.ex
+++ b/lib/cgrates_web_jsonapi/tenants.ex
@@ -101,4 +101,100 @@ defmodule CgratesWebJsonapi.Tenants do
   def change_tenant(%Tenant{} = tenant, attrs \\ %{}) do
     Tenant.update_changeset(tenant, attrs)
   end
+
+  alias CgratesWebJsonapi.Tenants.Membership
+
+  @doc """
+  Returns the list of memberships.
+
+  ## Examples
+
+      iex> list_memberships()
+      [%Membership{}, ...]
+
+  """
+  def list_memberships do
+    Repo.all(Membership)
+  end
+
+  @doc """
+  Gets a single membership.
+
+  Raises `Ecto.NoResultsError` if the Membership does not exist.
+
+  ## Examples
+
+      iex> get_membership!(123)
+      %Membership{}
+
+      iex> get_membership!(456)
+      ** (Ecto.NoResultsError)
+
+  """
+  def get_membership!(id), do: Repo.get!(Membership, id)
+
+  @doc """
+  Creates a membership.
+
+  ## Examples
+
+      iex> create_membership(%{field: value})
+      {:ok, %Membership{}}
+
+      iex> create_membership(%{field: bad_value})
+      {:error, %Ecto.Changeset{}}
+
+  """
+  def create_membership(attrs \\ %{}) do
+    %Membership{}
+    |> Membership.changeset(attrs)
+    |> Repo.insert()
+  end
+
+  @doc """
+  Updates a membership.
+
+  ## Examples
+
+      iex> update_membership(membership, %{field: new_value})
+      {:ok, %Membership{}}
+
+      iex> update_membership(membership, %{field: bad_value})
+      {:error, %Ecto.Changeset{}}
+
+  """
+  def update_membership(%Membership{} = membership, attrs) do
+    membership
+    |> Membership.changeset(attrs)
+    |> Repo.update()
+  end
+
+  @doc """
+  Deletes a membership.
+
+  ## Examples
+
+      iex> delete_membership(membership)
+      {:ok, %Membership{}}
+
+      iex> delete_membership(membership)
+      {:error, %Ecto.Changeset{}}
+
+  """
+  def delete_membership(%Membership{} = membership) do
+    Repo.delete(membership)
+  end
+
+  @doc """
+  Returns an `%Ecto.Changeset{}` for tracking membership changes.
+
+  ## Examples
+
+      iex> change_membership(membership)
+      %Ecto.Changeset{data: %Membership{}}
+
+  """
+  def change_membership(%Membership{} = membership, attrs \\ %{}) do
+    Membership.changeset(membership, attrs)
+  end
 end
diff --git a/lib/cgrates_web_jsonapi/tenants/membership.ex b/lib/cgrates_web_jsonapi/tenants/membership.ex
new file mode 100644
index 0000000..0e81299
--- /dev/null
+++ b/lib/cgrates_web_jsonapi/tenants/membership.ex
@@ -0,0 +1,22 @@
+defmodule CgratesWebJsonapi.Tenants.Membership do
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  alias CgratesWebJsonapi.Tenants.Tenant
+  alias CgratesWebJsonapi.Auth.User
+
+  schema "memberships" do
+    field :role, :integer
+    belongs_to :tenant, Tenant, type: :string
+    belongs_to :user, User
+
+    timestamps()
+  end
+
+  @doc false
+  def changeset(membership, attrs) do
+    membership
+    |> cast(attrs, [:role])
+    |> validate_required([:role])
+  end
+end
diff --git a/lib/cgrates_web_jsonapi_web/controllers/cdr_extra_field_controller.ex b/lib/cgrates_web_jsonapi_web/controllers/cdr_extra_field_controller.ex
new file mode 100644
index 0000000..8c0ce5d
--- /dev/null
+++ b/lib/cgrates_web_jsonapi_web/controllers/cdr_extra_field_controller.ex
@@ -0,0 +1,22 @@
+defmodule CgratesWebJsonapiWeb.CdrExtraFieldController do
+  use CgratesWebJsonapiWeb, :controller
+  use PhoenixSwagger
+
+  alias CgratesWebJsonapi.Cdrs
+  alias CgratesWebJsonapi.EtsCache
+
+  swagger_path :index do
+    get("/api/cdr-extra-fields")
+    CommonSwaggerParams.authorization()
+    CommonSwaggerParams.content_type()
+
+    description("An array of string values of used extra_fields")
+
+    response(200, "OK")
+  end
+
+  def index(conn, _) do
+    extra_fields = fn -> Cdrs.extra() end
+    render(conn, "extra_fields.json", data: EtsCache.get(extra_fields, :extra_fields))
+  end
+end
diff --git a/lib/cgrates_web_jsonapi_web/controllers/membership_controller.ex b/lib/cgrates_web_jsonapi_web/controllers/membership_controller.ex
new file mode 100644
index 0000000..eb8b206
--- /dev/null
+++ b/lib/cgrates_web_jsonapi_web/controllers/membership_controller.ex
@@ -0,0 +1,42 @@
+defmodule CgratesWebJsonapiWeb.MembershipController do
+  use CgratesWebJsonapiWeb, :controller
+
+  alias CgratesWebJsonapi.Tenants
+  alias CgratesWebJsonapi.Tenants.Membership
+
+  def index(conn, _params) do
+    memberships = Tenants.list_memberships()
+    render(conn, "index.json", memberships: memberships)
+  end
+
+  def create(conn, %{"membership" => membership_params}) do
+    with {:ok, %Membership{} = membership} <- Tenants.create_membership(membership_params) do
+      conn
+      |> put_status(:created)
+      |> put_resp_header("location", Routes.membership_path(conn, :show, membership))
+      |> render("show.json", membership: membership)
+    end
+  end
+
+  def show(conn, %{"id" => id}) do
+    membership = Tenants.get_membership!(id)
+    render(conn, "show.json", membership: membership)
+  end
+
+  def update(conn, %{"id" => id, "membership" => membership_params}) do
+    membership = Tenants.get_membership!(id)
+
+    with {:ok, %Membership{} = membership} <-
+           Tenants.update_membership(membership, membership_params) do
+      render(conn, "show.json", membership: membership)
+    end
+  end
+
+  def delete(conn, %{"id" => id}) do
+    membership = Tenants.get_membership!(id)
+
+    with {:ok, %Membership{}} <- Tenants.delete_membership(membership) do
+      send_resp(conn, :no_content, "")
+    end
+  end
+end
diff --git a/lib/cgrates_web_jsonapi_web/router.ex b/lib/cgrates_web_jsonapi_web/router.ex
index 13b7baa..a0e03db 100644
--- a/lib/cgrates_web_jsonapi_web/router.ex
+++ b/lib/cgrates_web_jsonapi_web/router.ex
@@ -104,8 +104,10 @@ defmodule CgratesWebJsonapiWeb.Router do
     post("/tp-timings/delete_all", TpTimingController, :delete_all)
     resources("/tp-timings", TpTimingController, except: [:new, :edit])
     resources("/users", UserController, except: [:new, :edit])
+    resources("/cdr-extra-fields", CdrExtraFieldController, only: [:index])
     resources("/cdr-stats", CdrStatController, only: [:index])
     resources("/tenants", TenantController, only: [:show, :update])
+    resources("/memberships", MembershipController)
   end
 
   scope "/uploaders", CgratesWebJsonapiWeb do
diff --git a/lib/cgrates_web_jsonapi_web/views/cdr_extra_field_view.ex b/lib/cgrates_web_jsonapi_web/views/cdr_extra_field_view.ex
new file mode 100644
index 0000000..3770c84
--- /dev/null
+++ b/lib/cgrates_web_jsonapi_web/views/cdr_extra_field_view.ex
@@ -0,0 +1,6 @@
+defmodule CgratesWebJsonapiWeb.CdrExtraFieldView do
+  use CgratesWebJsonapiWeb, :view
+  use JaSerializer.PhoenixView
+
+  def render("extra_fields.json", %{data: data}), do: data
+end
diff --git a/lib/cgrates_web_jsonapi_web/views/membership_view.ex b/lib/cgrates_web_jsonapi_web/views/membership_view.ex
new file mode 100644
index 0000000..79f4736
--- /dev/null
+++ b/lib/cgrates_web_jsonapi_web/views/membership_view.ex
@@ -0,0 +1,16 @@
+defmodule CgratesWebJsonapiWeb.MembershipView do
+  use CgratesWebJsonapiWeb, :view
+  alias CgratesWebJsonapiWeb.MembershipView
+
+  def render("index.json", %{memberships: memberships}) do
+    %{data: render_many(memberships, MembershipView, "membership.json")}
+  end
+
+  def render("show.json", %{membership: membership}) do
+    %{data: render_one(membership, MembershipView, "membership.json")}
+  end
+
+  def render("membership.json", %{membership: membership}) do
+    %{id: membership.id, role: membership.role}
+  end
+end
diff --git a/priv/repo/migrations/20210517174717_create_memberships.exs b/priv/repo/migrations/20210517174717_create_memberships.exs
new file mode 100644
index 0000000..54aaf51
--- /dev/null
+++ b/priv/repo/migrations/20210517174717_create_memberships.exs
@@ -0,0 +1,16 @@
+defmodule CgratesWebJsonapi.Repo.Migrations.CreateMemberships do
+  use Ecto.Migration
+
+  def change do
+    create table(:memberships) do
+      add(:role, :integer)
+      add(:tenant_id, references(:tenants, on_delete: :nothing, type: :string))
+      add(:user_id, references(:users, on_delete: :nothing))
+
+      timestamps()
+    end
+
+    create(index(:memberships, [:tenant_id]))
+    create(index(:memberships, [:user_id]))
+  end
+end
diff --git a/priv/static/swagger.json b/priv/static/swagger.json
index 5a4b2e5..7571ecf 100644
--- a/priv/static/swagger.json
+++ b/priv/static/swagger.json
@@ -384,6 +384,33 @@
           "Call"
         ]
       }
+    },
+    "/api/cdr-extra-fields": {
+      "get": {
+        "description": "An array of string values of used extra_fields",
+        "operationId": "CgratesWebJsonapiWeb.CdrExtraFieldController.index",
+        "parameters": [
+          {
+            "description": "OAuth2 access token",
+            "in": "header",
+            "name": "Authorization",
+            "required": true,
+            "type": "string"
+          }
+        ],
+        "produces": [
+          "application/vnd.api+json"
+        ],
+        "responses": {
+          "200": {
+            "description": "OK"
+          }
+        },
+        "summary": "",
+        "tags": [
+          "CdrExtraField"
+        ]
+      }
     }
   },
   "swagger": "2.0",
diff --git a/test/cgrates_web_jsonapi/tenants_test.exs b/test/cgrates_web_jsonapi/tenants_test.exs
index 1f072d0..f032bc3 100644
--- a/test/cgrates_web_jsonapi/tenants_test.exs
+++ b/test/cgrates_web_jsonapi/tenants_test.exs
@@ -66,4 +66,63 @@ defmodule CgratesWebJsonapi.TenantsTest do
       assert %Ecto.Changeset{} = Tenants.change_tenant(tenant)
     end
   end
+
+  describe "memberships" do
+    alias CgratesWebJsonapi.Tenants.Membership
+
+    @valid_attrs %{role: 42}
+    @update_attrs %{role: 43}
+    @invalid_attrs %{role: nil}
+
+    def membership_fixture(attrs \\ %{}) do
+      {:ok, membership} =
+        attrs
+        |> Enum.into(@valid_attrs)
+        |> Tenants.create_membership()
+
+      membership
+    end
+
+    test "list_memberships/0 returns all memberships" do
+      membership = membership_fixture()
+      assert Tenants.list_memberships() == [membership]
+    end
+
+    test "get_membership!/1 returns the membership with given id" do
+      membership = membership_fixture()
+      assert Tenants.get_membership!(membership.id) == membership
+    end
+
+    test "create_membership/1 with valid data creates a membership" do
+      assert {:ok, %Membership{} = membership} = Tenants.create_membership(@valid_attrs)
+      assert membership.role == 42
+    end
+
+    test "create_membership/1 with invalid data returns error changeset" do
+      assert {:error, %Ecto.Changeset{}} = Tenants.create_membership(@invalid_attrs)
+    end
+
+    test "update_membership/2 with valid data updates the membership" do
+      membership = membership_fixture()
+      assert {:ok, %Membership{} = membership} = Tenants.update_membership(membership, @update_attrs)
+      assert membership.role == 43
+    end
+
+    test "update_membership/2 with invalid data returns error changeset" do
+      membership = membership_fixture()
+      assert {:error, %Ecto.Changeset{}} = Tenants.update_membership(membership, @invalid_attrs)
+      assert membership == Tenants.get_membership!(membership.id)
+    end
+
+    test "delete_membership/1 deletes the membership" do
+      membership = membership_fixture()
+      assert {:ok, %Membership{}} = Tenants.delete_membership(membership)
+      assert_raise Ecto.NoResultsError, fn -> Tenants.get_membership!(membership.id) end
+    end
+
+    test "change_membership/1 returns a membership changeset" do
+      membership = membership_fixture()
+      assert %Ecto.Changeset{} = Tenants.change_membership(membership)
+    end
+  end
 end
diff --git a/test/cgrates_web_jsonapi_web/controllers/cdr_extra_field_controller_test.exs b/test/cgrates_web_jsonapi_web/controllers/cdr_extra_field_controller_test.exs
new file mode 100644
index 0000000..ee411c2
--- /dev/null
+++ b/test/cgrates_web_jsonapi_web/controllers/cdr_extra_field_controller_test.exs
@@ -0,0 +1,36 @@
+defmodule CgratesWebJsonapiWeb.CdrExtraFieldControllerTest do
+  use CgratesWebJsonapi.ConnCase
+
+  alias CgratesWebJsonapi.Cdrs.Cdr
+  alias CgratesWebJsonapi.Repo
+
+  import CgratesWebJsonapi.Factory
+  import CgratesWebJsonapi.Guardian
+
+  setup do
+    user = insert(:user)
+
+    {:ok, token, _} = encode_and_sign(user, %{}, token_type: :access)
+
+    conn =
+      build_conn()
+      |> put_req_header("accept", "application/vnd.api+json")
+      |> put_req_header("content-type", "application/vnd.api+json")
+      |> put_req_header("authorization", "bearer: " <> token)
+
+    {:ok, conn: conn}
+  end
+
+  test "cdrs extra fields list", %{conn: conn} do
+    cdr1 = insert(:cdr, destination: "123", account: "1")
+    cdr2 = insert(:cdr, destination: "987", account: "2")
+
+    conn =
+      conn
+      |> get(Routes.cdr_extra_field_path(conn, :index))
+
+    response = json_response(conn, 200)
+
+    assert response == ["cost"]
+  end
+end
diff --git a/test/cgrates_web_jsonapi_web/controllers/membership_controller_test.exs b/test/cgrates_web_jsonapi_web/controllers/membership_controller_test.exs
new file mode 100644
index 0000000..38e2fec
--- /dev/null
+++ b/test/cgrates_web_jsonapi_web/controllers/membership_controller_test.exs
@@ -0,0 +1,93 @@
+defmodule CgratesWebJsonapiWeb.MembershipControllerTest do
+  use CgratesWebJsonapi.ConnCase
+
+  alias CgratesWebJsonapi.Tenants
+  alias CgratesWebJsonapi.Tenants.Membership
+
+  alias CgratesWebJsonapi.Cdrs.Cdr
+  alias CgratesWebJsonapi.Repo
+
+  import CgratesWebJsonapi.Factory
+  import CgratesWebJsonapi.Guardian
+
+  @create_attrs %{
+    role: 42
+  }
+
+  @update_attrs %{
+    role: 43
+  }
+
+  setup do
+    user = insert(:user)
+
+    {:ok, token, _} = encode_and_sign(user, %{}, token_type: :access)
+
+    conn =
+      build_conn()
+      |> put_req_header("accept", "application/vnd.api+json")
+      |> put_req_header("content-type", "application/vnd.api+json")
+      |> put_req_header("authorization", "bearer: " <> token)
+
+    {:ok, conn: conn}
+  end
+
+  describe "index" do
+    test "lists all memberships", %{conn: conn} do
+      insert(:membership)
+      conn = get(conn, Routes.membership_path(conn, :index))
+
+      assert length(json_response(conn, 200)["data"]) == 1
+    end
+  end
+
+  describe "show" do
+    test "show one memberships", %{conn: conn} do
+      membership = insert(:membership, role: 1)
+      conn = get(conn, Routes.membership_path(conn, :show, membership)) |> doc
+
+      data = json_response(conn, 200)["data"]
+      assert data["id"] == membership.id
+      assert data["role"] == 1
+    end
+  end
+
+  describe "create membership" do
+    test "renders membership when data is valid", %{conn: conn} do
+      conn = post(conn, Routes.membership_path(conn, :create), membership: @create_attrs)
+      assert %{"id" => id} = json_response(conn, 201)["data"]
+
+      conn = get(conn, Routes.membership_path(conn, :show, id))
+
+      assert %{
+               "id" => id,
+               "role" => 42
+             } = json_response(conn, 200)["data"]
+    end
+  end
+
+  describe "update membership" do
+    test "update chosen membership", %{conn: conn} do
+      membership = insert(:membership, role: 1)
+
+      id = membership.id
+      conn = put(conn, Routes.membership_path(conn, :update, id), membership: @update_attrs)
+      assert json_response(conn, 200)["data"]["id"]
+
+      assert json_response(conn, 200)["data"]["role"] == @update_attrs[:role]
+    end
+  end
+
+  describe "delete membership" do
+    test "deletes chosen membership", %{conn: conn} do
+      membership = insert(:membership, role: 1)
+
+      conn = delete(conn, Routes.membership_path(conn, :delete, membership))
+      assert response(conn, 204)
+
+      assert_error_sent 404, fn ->
+        get(conn, Routes.membership_path(conn, :show, membership))
+      end
+    end
+  end
+end
diff --git a/test/support/factory.ex b/test/support/factory.ex
index 9de0454..6267059 100644
--- a/test/support/factory.ex
+++ b/test/support/factory.ex
@@ -310,4 +310,12 @@ defmodule CgratesWebJsonapi.Factory do
       id: UUID.uuid4()
     }
   end
+
+  def membership_factory do
+    %CgratesWebJsonapi.Tenants.Membership{
+      id: sequence(:id, fn n -> n end),
+      tenant_id: insert(:tenant).id,
+      user_id: insert(:user).id
+    }
+  end
 end