diff --git a/config/dev.exs b/config/dev.exs
index 514e2e00..5a165620 100644
--- a/config/dev.exs
+++ b/config/dev.exs
@@ -73,3 +73,7 @@ config :tesla_mate, TeslaMate.Repo,
   database: "tesla_mate_dev",
   hostname: "localhost",
   pool_size: 10
+
+config :tesla_mate, :tesla_auth,
+  username: System.get_env("USERNAME"),
+  password: System.get_env("PASSWOrD")
diff --git a/lib/tesla_mate/api.ex b/lib/tesla_mate/api.ex
new file mode 100644
index 00000000..c791a6da
--- /dev/null
+++ b/lib/tesla_mate/api.ex
@@ -0,0 +1,97 @@
+defmodule TeslaMate.Api do
+  use GenServer
+
+  require Logger
+  import Core.Dependency, only: [call: 3]
+  alias TeslaApi.{Auth, Error, Vehicle}
+
+  defstruct auth: nil,
+            deps: %{}
+
+  alias __MODULE__, as: State
+
+  @name __MODULE__
+
+  if Mix.env() === :prod do
+    # API
+
+    def start_link(opts) do
+      GenServer.start_link(__MODULE__, opts, name: Keyword.get(opts, :name, @name))
+    end
+
+    def list_vehicles(name \\ @name) do
+      GenServer.call(name, :list_vehicles)
+    end
+
+    def charge_state(name \\ @name, vehicle_id) do
+      GenServer.call(name, {:charge_state, vehicle_id})
+    end
+
+    # Callbacks
+
+    @impl true
+    def init(opts) do
+      username = Keyword.fetch!(opts, :username)
+      password = Keyword.fetch!(opts, :password)
+
+      case Auth.login(username, password) do
+        %Error{error: error, message: reason, env: _env} ->
+          Logger.error("Login failed: #{inspect({error, reason})}")
+          {:stop, {error, reason}}
+
+        %Auth{} = auth ->
+          Logger.info("Login successful")
+          {:ok, %State{auth: auth}, {:continue, :schedule_refresh}}
+      end
+    end
+
+    @impl true
+    def handle_call({:charge_state, vehicle_id}, _from, state) do
+      case Vehicle.State.charge_state(state.auth, vehicle_id) do
+        %Vehicle.State.Charge{} = charge_state -> {:reply, charge_state, state}
+        %Error{message: reason} -> {:reply, {:error, reason}, state}
+      end
+    end
+
+    def handle_call(:list_vehicles, _from, state) do
+      case Vehicle.list(state.auth) do
+        vehicles when is_list(vehicles) -> {:reply, {:ok, vehicles}, state}
+        %Error{message: reason} -> {:reply, {:error, reason}, state}
+      end
+    end
+
+    @impl true
+    def handle_info(:refresh_auth, %State{auth: auth} = state) do
+      case Auth.refresh(auth) do
+        %Auth{} = auth -> {:noreply, %State{state | auth: auth}, {:continue, :schedule_refresh}}
+        %Error{error: error, message: reason, env: _} -> {:stop, {error, reason}}
+      end
+    end
+
+    @impl true
+    def handle_continue(:schedule_refresh, state) do
+      Process.send_after(self(), :refresh_auth, :timer.hours(24 * 30))
+      {:noreply, state}
+    end
+  else
+    # API
+
+    def start_link(opts) do
+      GenServer.start_link(__MODULE__, opts, name: Keyword.get(opts, :name, @name))
+    end
+
+    def charge_state(vehicle_id) do
+      {:ok, %Vehicle.State.Charge{}}
+    end
+
+    def list_vehicles do
+      {:ok,
+       [%Vehicle{vehicle_id: 0, display_name: "Tesla!M3", option_codes: ["MDL3", "BT37", "DV4W"]}]}
+    end
+
+    @impl true
+    def init(opts) do
+      {:ok, nil}
+    end
+  end
+end
diff --git a/lib/tesla_mate/application.ex b/lib/tesla_mate/application.ex
index 2d5386a8..d48f2e4b 100644
--- a/lib/tesla_mate/application.ex
+++ b/lib/tesla_mate/application.ex
@@ -6,20 +6,14 @@ defmodule TeslaMate.Application do
   use Application
 
   def start(_type, _args) do
-    # List all child processes to be supervised
     children = [
-      # Start the Ecto repository
       TeslaMate.Repo,
-      # Start the endpoint when the application starts
-      TeslaMateWeb.Endpoint
-      # Starts a worker by calling: TeslaMate.Worker.start_link(arg)
-      # {TeslaMate.Worker, arg},
+      TeslaMateWeb.Endpoint,
+      {TeslaMate.Api, auth()},
+      TeslaMate.Vehicles
     ]
 
-    # See https://hexdocs.pm/elixir/Supervisor.html
-    # for other strategies and supported options
-    opts = [strategy: :one_for_one, name: TeslaMate.Supervisor]
-    Supervisor.start_link(children, opts)
+    Supervisor.start_link(children, strategy: :one_for_one, name: TeslaMate.Supervisor)
   end
 
   # Tell Phoenix to update the endpoint configuration
@@ -28,4 +22,8 @@ defmodule TeslaMate.Application do
     TeslaMateWeb.Endpoint.config_change(changed, removed)
     :ok
   end
+
+  defp auth do
+    Application.get_env(:tesla_mate, :tesla_auth)
+  end
 end
diff --git a/lib/tesla_mate/dependency.ex b/lib/tesla_mate/dependency.ex
new file mode 100644
index 00000000..0b65860e
--- /dev/null
+++ b/lib/tesla_mate/dependency.ex
@@ -0,0 +1,4 @@
+defmodule Core.Dependency do
+  def call({m, a}, fun, args), do: apply(m, fun, [a] ++ args)
+  def call(m, f, a), do: apply(m, f, a)
+end
diff --git a/lib/tesla_mate/vehicles.ex b/lib/tesla_mate/vehicles.ex
new file mode 100644
index 00000000..45011a9c
--- /dev/null
+++ b/lib/tesla_mate/vehicles.ex
@@ -0,0 +1,28 @@
+defmodule TeslaMate.Vehicles do
+  use Supervisor
+
+  alias __MODULE__.Vehicle
+
+  @name __MODULE__
+
+  def start_link(opts) do
+    Supervisor.start_link(__MODULE__, opts, name: @name)
+  end
+
+  @impl true
+  def init(opts) do
+    vehicles =
+      Keyword.get_lazy(opts, :vehicles, fn ->
+        {:ok, vehicles} = TeslaMate.Api.list_vehicles()
+        vehicles
+      end)
+
+    children =
+      vehicles
+      |> Enum.map(fn %TeslaApi.Vehicle{} = vehicle ->
+        {Vehicle, vehicle}
+      end)
+
+    Supervisor.init(children, strategy: :one_for_one, max_restarts: 5, max_seconds: 60)
+  end
+end
diff --git a/lib/tesla_mate/vehicles/vehicle.ex b/lib/tesla_mate/vehicles/vehicle.ex
new file mode 100644
index 00000000..a9bca424
--- /dev/null
+++ b/lib/tesla_mate/vehicles/vehicle.ex
@@ -0,0 +1,35 @@
+defmodule TeslaMate.Vehicles.Vehicle do
+  use GenServer
+
+  require Logger
+
+  alias __MODULE__.Identification
+
+  # import Core.Dependency, only: [call: 3]
+
+  defstruct id: nil,
+            properties: nil,
+            deps: %{}
+
+  alias __MODULE__, as: State
+
+  def start_link(opts) do
+    GenServer.start_link(__MODULE__, opts, [])
+  end
+
+  @impl true
+  def init(%TeslaApi.Vehicle{} = vehicle) do
+    properties = Identification.properties(vehicle)
+
+    Logger.info("Found Vehicle '#{vehicle.display_name}' [#{inspect(properties)}]")
+
+    {:ok, %State{id: vehicle.vehicle_id, properties: properties}, {:continue, :init}}
+  end
+
+  @impl true
+  def handle_continue(:init, state) do
+    {:noreply, state}
+  end
+
+  # Private
+end
diff --git a/lib/tesla_mate/vehicles/vehicle/identification.ex b/lib/tesla_mate/vehicles/vehicle/identification.ex
new file mode 100644
index 00000000..5dec6dac
--- /dev/null
+++ b/lib/tesla_mate/vehicles/vehicle/identification.ex
@@ -0,0 +1,62 @@
+defmodule TeslaMate.Vehicles.Vehicle.Identification do
+  def properties(%TeslaApi.Vehicle{} = vehicle) do
+    performance = vehicle.option_codes |> Enum.find(false, &is_performance/1)
+    battery = vehicle.option_codes |> Enum.find_value(&which_battery/1)
+    model = vehicle.option_codes |> Enum.find_value(&which_model/1)
+    awd = vehicle.option_codes |> Enum.member?("DV4W")
+
+    {name, efficiency} = get_efficiency(model, battery, performance, awd)
+
+    %{
+      name: name,
+      model: model,
+      battery: battery,
+      awd: awd,
+      performance: performance,
+      efficiency: efficiency
+    }
+  end
+
+  defp which_model("MDLS"), do: "MS"
+  defp which_model("MS01"), do: "MS"
+  defp which_model("MS02"), do: "MS"
+  defp which_model("MS03"), do: "MS"
+  defp which_model("MDLX"), do: "MX"
+  defp which_model("MDL3"), do: "M3"
+  defp which_model(______), do: false
+
+  defp is_performance("PX01"), do: true
+  defp is_performance("P85D"), do: true
+  defp is_performance("PX6D"), do: true
+  defp is_performance("X024"), do: true
+  defp is_performance("PBT8"), do: true
+  defp is_performance(______), do: nil
+
+  defp which_battery("BT" <> _ = battery), do: battery
+  defp which_battery(_), do: nil
+
+  defp get_efficiency("MS", "BTX5", _, true), do: {"S 75D", 0.186}
+  defp get_efficiency("MS", "BTX5", _, false), do: {"S 75", 0.185}
+  defp get_efficiency("MS", "BTX4", true, _), do: {"S P90D", 0.200}
+  defp get_efficiency("MS", "BTX4", false, _), do: {"S 90D", 0.189}
+  defp get_efficiency("MS", "BTX6", true, _), do: {"S P100D", 0.200}
+  defp get_efficiency("MS", "BTX6", false, _), do: {"S 100D", 0.189}
+  defp get_efficiency("MS", "BTX8", _, true), do: {"S 75D (85kWh)", 0.186}
+  defp get_efficiency("MS", "BTX8", _, false), do: {"S 75 (85kWh)", 0.185}
+  defp get_efficiency("MS", "BT85", _, _), do: {"S 85 ?", 0.200}
+  defp get_efficiency("MS", "BT70", _, _), do: {"S 70 ?", 0.200}
+  defp get_efficiency("MS", "BT60", _, _), do: {"S 60 ?", 0.200}
+  defp get_efficiency("MS", _, _, _), do: {"S ???", 0.200}
+
+  defp get_efficiency("MX", "BTX5", _, _), do: {"X 75D", 0.208}
+  defp get_efficiency("MX", "BTX4", true, _), do: {"X 90D", 0.208}
+  defp get_efficiency("MX", "BTX4", false, _), do: {"X P90D", 0.217}
+  defp get_efficiency("MX", "BTX6", true, _), do: {"X P100D", 0.226}
+  defp get_efficiency("MX", "BTX6", false, _), do: {"X 100D", 0.208}
+  defp get_efficiency("MX", _, _, _), do: {"X ???", 0.208}
+
+  defp get_efficiency("M3", "BT37", _, _), do: {"M3 LR", 0.153}
+  defp get_efficiency("M3", _, _, _), do: {"M3 ???", 0.153}
+
+  defp get_efficiency(_, _, _, _), do: {"???", nil}
+end
diff --git a/mix.exs b/mix.exs
index 58a9fc77..ca20daaf 100644
--- a/mix.exs
+++ b/mix.exs
@@ -33,6 +33,7 @@ defmodule TeslaMate.MixProject do
   # Type `mix help deps` for examples and options.
   defp deps do
     [
+      # Default
       {:phoenix, "~> 1.4.3"},
       {:phoenix_pubsub, "~> 1.1"},
       {:phoenix_ecto, "~> 4.0"},
@@ -43,6 +44,8 @@ defmodule TeslaMate.MixProject do
       {:gettext, "~> 0.11"},
       {:jason, "~> 1.0"},
       {:plug_cowboy, "~> 2.0"},
+      # Custom
+      {:tesla_api, git: "https://github.com/mgwidmann/tesla_api"}
     ]
   end
 
diff --git a/mix.lock b/mix.lock
new file mode 100644
index 00000000..a768eabf
--- /dev/null
+++ b/mix.lock
@@ -0,0 +1,34 @@
+%{
+  "certifi": {:hex, :certifi, "2.4.2", "75424ff0f3baaccfd34b1214184b6ef616d89e420b258bb0a5ea7d7bc628f7f0", [:rebar3], [{:parse_trans, "~>3.3", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm"},
+  "connection": {:hex, :connection, "1.0.4", "a1cae72211f0eef17705aaededacac3eb30e6625b04a6117c1b2db6ace7d5976", [:mix], [], "hexpm"},
+  "cowboy": {:hex, :cowboy, "2.6.1", "f2e06f757c337b3b311f9437e6e072b678fcd71545a7b2865bdaa154d078593f", [:rebar3], [{:cowlib, "~> 2.7.0", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "~> 1.7.1", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm"},
+  "cowlib": {:hex, :cowlib, "2.7.0", "3ef16e77562f9855a2605900cedb15c1462d76fb1be6a32fc3ae91973ee543d2", [:rebar3], [], "hexpm"},
+  "db_connection": {:hex, :db_connection, "2.0.6", "bde2f85d047969c5b5800cb8f4b3ed6316c8cb11487afedac4aa5f93fd39abfa", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}], "hexpm"},
+  "decimal": {:hex, :decimal, "1.7.0", "30d6b52c88541f9a66637359ddf85016df9eb266170d53105f02e4a67e00c5aa", [:mix], [], "hexpm"},
+  "ecto": {:hex, :ecto, "3.0.8", "9eb6a1fcfc593e6619d45ef51afe607f1554c21ca188a1cd48eecc27223567f1", [:mix], [{:decimal, "~> 1.6", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:poison, "~> 2.2 or ~> 3.0", [hex: :poison, repo: "hexpm", optional: true]}], "hexpm"},
+  "ecto_sql": {:hex, :ecto_sql, "3.0.5", "7e44172b4f7aca4469f38d7f6a3da394dbf43a1bcf0ca975e958cb957becd74e", [:mix], [{:db_connection, "~> 2.0", [hex: :db_connection, repo: "hexpm", optional: false]}, {:ecto, "~> 3.0.6", [hex: :ecto, repo: "hexpm", optional: false]}, {:mariaex, "~> 0.9.1", [hex: :mariaex, repo: "hexpm", optional: true]}, {:postgrex, "~> 0.14.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.3.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm"},
+  "file_system": {:hex, :file_system, "0.2.6", "fd4dc3af89b9ab1dc8ccbcc214a0e60c41f34be251d9307920748a14bf41f1d3", [:mix], [], "hexpm"},
+  "gettext": {:hex, :gettext, "0.16.1", "e2130b25eebcbe02bb343b119a07ae2c7e28bd4b146c4a154da2ffb2b3507af2", [:mix], [], "hexpm"},
+  "hackney": {:hex, :hackney, "1.14.3", "b5f6f5dcc4f1fba340762738759209e21914516df6be440d85772542d4a5e412", [:rebar3], [{:certifi, "2.4.2", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "6.0.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "1.0.2", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.4", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
+  "idna": {:hex, :idna, "6.0.0", "689c46cbcdf3524c44d5f3dde8001f364cd7608a99556d8fbd8239a5798d4c10", [:rebar3], [{:unicode_util_compat, "0.4.1", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm"},
+  "jason": {:hex, :jason, "1.1.2", "b03dedea67a99223a2eaf9f1264ce37154564de899fd3d8b9a21b1a6fd64afe7", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm"},
+  "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm"},
+  "mime": {:hex, :mime, "1.3.1", "30ce04ab3175b6ad0bdce0035cba77bba68b813d523d1aac73d9781b4d193cf8", [:mix], [], "hexpm"},
+  "mimerl": {:hex, :mimerl, "1.0.2", "993f9b0e084083405ed8252b99460c4f0563e41729ab42d9074fd5e52439be88", [:rebar3], [], "hexpm"},
+  "parse_trans": {:hex, :parse_trans, "3.3.0", "09765507a3c7590a784615cfd421d101aec25098d50b89d7aa1d66646bc571c1", [:rebar3], [], "hexpm"},
+  "phoenix": {:hex, :phoenix, "1.4.3", "8eed4a64ff1e12372cd634724bddd69185938f52c18e1396ebac76375d85677d", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 1.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:plug, "~> 1.7", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 1.0 or ~> 2.0", [hex: :plug_cowboy, repo: "hexpm", optional: true]}], "hexpm"},
+  "phoenix_ecto": {:hex, :phoenix_ecto, "4.0.0", "c43117a136e7399ea04ecaac73f8f23ee0ffe3e07acfcb8062fe5f4c9f0f6531", [:mix], [{:ecto, "~> 3.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 2.9", [hex: :phoenix_html, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm"},
+  "phoenix_html": {:hex, :phoenix_html, "2.13.2", "f5d27c9b10ce881a60177d2b5227314fc60881e6b66b41dfe3349db6ed06cf57", [:mix], [{:plug, "~> 1.5", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm"},
+  "phoenix_live_reload": {:hex, :phoenix_live_reload, "1.2.0", "3bb31a9fbd40ffe8652e60c8660dffd72dd231efcdf49b744fb75b9ef7db5dd2", [:mix], [{:file_system, "~> 0.2.1 or ~> 0.3", [hex: :file_system, repo: "hexpm", optional: false]}, {:phoenix, "~> 1.4", [hex: :phoenix, repo: "hexpm", optional: false]}], "hexpm"},
+  "phoenix_pubsub": {:hex, :phoenix_pubsub, "1.1.2", "496c303bdf1b2e98a9d26e89af5bba3ab487ba3a3735f74bf1f4064d2a845a3e", [:mix], [], "hexpm"},
+  "plug": {:hex, :plug, "1.7.2", "d7b7db7fbd755e8283b6c0a50be71ec0a3d67d9213d74422d9372effc8e87fd1", [:mix], [{:mime, "~> 1.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}], "hexpm"},
+  "plug_cowboy": {:hex, :plug_cowboy, "2.0.2", "6055f16868cc4882b24b6e1d63d2bada94fb4978413377a3b32ac16c18dffba2", [:mix], [{:cowboy, "~> 2.5", [hex: :cowboy, repo: "hexpm", optional: false]}, {:plug, "~> 1.7", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm"},
+  "plug_crypto": {:hex, :plug_crypto, "1.0.0", "18e49317d3fa343f24620ed22795ec29d4a5e602d52d1513ccea0b07d8ea7d4d", [:mix], [], "hexpm"},
+  "postgrex": {:hex, :postgrex, "0.14.1", "63247d4a5ad6b9de57a0bac5d807e1c32d41e39c04b8a4156a26c63bcd8a2e49", [:mix], [{:connection, "~> 1.0", [hex: :connection, repo: "hexpm", optional: false]}, {:db_connection, "~> 2.0", [hex: :db_connection, repo: "hexpm", optional: false]}, {:decimal, "~> 1.5", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}], "hexpm"},
+  "ranch": {:hex, :ranch, "1.7.1", "6b1fab51b49196860b733a49c07604465a47bdb78aa10c1c16a3d199f7f8c881", [:rebar3], [], "hexpm"},
+  "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.4", "f0eafff810d2041e93f915ef59899c923f4568f4585904d010387ed74988e77b", [:make, :mix, :rebar3], [], "hexpm"},
+  "telemetry": {:hex, :telemetry, "0.3.0", "099a7f3ce31e4780f971b4630a3c22ec66d22208bc090fe33a2a3a6a67754a73", [:rebar3], [], "hexpm"},
+  "tesla": {:hex, :tesla, "1.2.1", "864783cc27f71dd8c8969163704752476cec0f3a51eb3b06393b3971dc9733ff", [:mix], [{:exjsx, ">= 3.0.0", [hex: :exjsx, repo: "hexpm", optional: true]}, {:fuse, "~> 2.4", [hex: :fuse, repo: "hexpm", optional: true]}, {:hackney, "~> 1.6", [hex: :hackney, repo: "hexpm", optional: true]}, {:ibrowse, "~> 4.4.0", [hex: :ibrowse, repo: "hexpm", optional: true]}, {:jason, ">= 1.0.0", [hex: :jason, repo: "hexpm", optional: true]}, {:mime, "~> 1.0", [hex: :mime, repo: "hexpm", optional: false]}, {:poison, ">= 1.0.0", [hex: :poison, repo: "hexpm", optional: true]}], "hexpm"},
+  "tesla_api": {:git, "https://github.com/mgwidmann/tesla_api", "15001942824940b808b6d67672d2b47bf2297623", []},
+  "unicode_util_compat": {:hex, :unicode_util_compat, "0.4.1", "d869e4c68901dd9531385bb0c8c40444ebf624e60b6962d95952775cac5e90cd", [:rebar3], [], "hexpm"},
+}