diff --git a/config/config.exs b/config/config.exs
index 0a8e523..12dae8f 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -12,8 +12,9 @@ config :stripe_mock, StripeMockWeb.Endpoint,
   url: [host: "localhost"],
   http: [:inet6, port: System.get_env("PORT") || 12111],
   secret_key_base: "ug9ATr9o7f/N2inxnW+SlrNVP7Ok+f9gAP43yHfqqm/bgFZSLeY6vQOY+wp562Iz",
-  render_errors: [view: StripeMockWeb.ErrorView, accepts: ~w(json)],
-  pubsub: [name: StripeMock.PubSub, adapter: Phoenix.PubSub.PG2]
+  render_errors: [view: StripeMockWeb.ErrorView, accepts: ~w(json)]
+
+config :stripe_mock, ecto_repos: [StripeMock.Repo]
 
 # Configures Elixir's Logger
 config :logger, :console,
@@ -23,6 +24,20 @@ config :logger, :console,
 # Use Jason for JSON parsing in Phoenix
 config :phoenix, :json_library, Jason
 
+{uri, _} = System.cmd("pg_tmp", ["-t"])
+
+[username, host, port, database] =
+  Regex.scan(~r/(\w+)@([\w\d\.]+)\:(\d+)\/(\w+)/i, uri, capture: :all_but_first) |> List.flatten()
+
+config :stripe_mock, StripeMock.Repo,
+  username: username,
+  password: "",
+  database: database,
+  hostname: host,
+  port: port,
+  pool_size: 2,
+  migration_primary_key: [name: :id, type: :binary_id]
+
 # Import environment specific config. This must remain at the bottom
 # of this file so it overrides the configuration defined above.
 import_config "#{Mix.env()}.exs"
diff --git a/lib/stripe_mock/api/card.ex b/lib/stripe_mock/api/card.ex
index 0e2e67a..8359837 100644
--- a/lib/stripe_mock/api/card.ex
+++ b/lib/stripe_mock/api/card.ex
@@ -3,9 +3,8 @@ defmodule StripeMock.API.Card do
 
   schema "cards" do
     field :brand, :string
-    field :created, :integer
     field :deleted, :boolean
-    field :metadata, StripeMock.Type.Metadata, default: %{}
+    field :metadata, :map, default: %{}
     field :last4, :string
     field :source, :string
 
@@ -15,6 +14,8 @@ defmodule StripeMock.API.Card do
     field :cvc, :string
 
     belongs_to :customer, API.Customer
+
+    timestamps()
   end
 
   @doc false
diff --git a/lib/stripe_mock/api/charge.ex b/lib/stripe_mock/api/charge.ex
index 427e095..7cf1340 100644
--- a/lib/stripe_mock/api/charge.ex
+++ b/lib/stripe_mock/api/charge.ex
@@ -1,19 +1,22 @@
 defmodule StripeMock.API.Charge do
   use StripeMock.Schema
-  alias StripeMock.Repo
 
-  @foreign_key_type :binary_id
   schema "charges" do
     field :amount, :integer
     field :capture, :boolean, default: false
     field :currency, :string
     field :description, :string
-    field :metadata, StripeMock.Type.Metadata, default: %{}
+    field :metadata, :map, default: %{}
     field :statement_descriptor, :string
     field :transfer_group, :string
 
+    field :source, :string, virtual: true
+
     belongs_to :customer, API.Customer
-    belongs_to :source, API.Card
+    belongs_to :card, API.Card
+    belongs_to :token, API.Token
+
+    timestamps()
   end
 
   @doc false
@@ -26,25 +29,24 @@ defmodule StripeMock.API.Charge do
       :customer_id,
       :description,
       :metadata,
-      :source_id,
+      :source,
       :statement_descriptor,
       :transfer_group
     ])
-    |> validate_required([:amount, :currency])
     |> set_customer_and_source()
-    |> validate_required(:source_id)
+    |> validate_required([:amount, :currency, :card_id])
+    |> put_common_fields()
   end
 
   @doc false
   def update_changeset(charge, attrs) do
     charge
     |> cast(attrs, [
-      :customer_id,
       :description,
       :metadata,
       :transfer_group
     ])
-    |> validate_required([:amount, :currency])
+    |> put_common_fields()
   end
 
   @doc false
@@ -52,73 +54,38 @@ defmodule StripeMock.API.Charge do
   end
 
   defp set_customer_and_source(changeset) do
-    customer =
-      with customer_id when not is_nil(customer_id) <- get_field(changeset, :customer_id) do
-        case Repo.fetch(API.Customer, customer_id) do
-          {:ok, customer} -> customer
-          _ -> throw({:not_found, :customer_id})
-        end
-      else
-        _ -> nil
-      end
-
     source =
-      case fetch_source(get_field(changeset, :source_id)) do
-        :invalid -> throw({:not_found, :source_id})
+      case fetch_source(get_field(changeset, :source)) do
+        nil -> throw({:not_found, :source})
         source -> source
       end
 
-    case {get_field(changeset, :customer_id), get_field(changeset, :source_id)} do
-      {nil, nil} ->
-        validate_required(changeset, :source_id)
-
-      {nil, _source_id} ->
-        case source do
-          %{card: %{customer_id: nil}} -> changeset
-          _ -> validate_required(changeset, :customer_id)
-        end
-
-      {customer_id, nil} ->
-        # TODO: Get the default payment method.
-        API.Card
-        |> Repo.all()
-        |> Enum.filter(&(&1.customer_id == customer_id))
-        |> case do
-          [source | _] -> put_change(changeset, :source_id, source.id)
-          [] -> throw({:not_found, :source_id})
-        end
-
-      {nil, "card_" <> _} ->
-        throw({:not_found, :source_id})
-
-      {_customer_id, "card_" <> _} ->
-        if source.customer_id != customer.id do
-          throw({:not_found, :source_id})
-        else
-          changeset
-        end
+    case source do
+      nil ->
+        add_error(changeset, :base, "either source or customer is required")
 
-      {_customer_id, "tok_" <> _} ->
+      %API.Card{} ->
         changeset
+        |> put_change(:card_id, source.id)
+        |> validate_required(:customer_id)
 
-      _ ->
-        add_error(changeset, :base, "either source or customer is required")
+      %API.Token{} ->
+        changeset
+        |> put_change(:token_id, source.id)
+        |> put_change(:card_id, source.card_id)
     end
-    |> ensure_source()
   catch
     {:not_found, field} -> add_error(changeset, field, "not found")
   end
 
-  defp ensure_source(changeset) do
-    with source when is_map(source) <- fetch_source(get_field(changeset, :source_id)) do
-      changeset
-    else
-      _ -> add_error(changeset, :source, "is invalid")
-    end
+  defp fetch_source(nil) do
+    nil
   end
 
-  defp fetch_source("tok_" <> _ = token_id), do: Repo.get(API.Token, token_id)
-  defp fetch_source("card_" <> _ = card_id), do: Repo.get(API.Card, card_id)
-  defp fetch_source(nil), do: nil
-  defp fetch_source(_), do: :invalid
+  defp fetch_source(source) do
+    card = Repo.get(API.Card, source)
+    token = Repo.get(API.Token, source)
+
+    card || token
+  end
 end
diff --git a/lib/stripe_mock/api/customer.ex b/lib/stripe_mock/api/customer.ex
index 29685c1..c57d655 100644
--- a/lib/stripe_mock/api/customer.ex
+++ b/lib/stripe_mock/api/customer.ex
@@ -1,16 +1,16 @@
 defmodule StripeMock.API.Customer do
   use StripeMock.Schema
 
-  @primary_key {:id, :binary_id, autogenerate: false}
   schema "customers" do
-    field :created, :integer
     field :currency, :string, default: "usd"
     field :deleted, :boolean, default: false
     field :description, :string
     field :email, :string
-    field :metadata, StripeMock.Type.Metadata, default: %{}
+    field :metadata, :map, default: %{}
     field :name, :string
     field :phone, :string
+
+    timestamps()
   end
 
   @doc false
diff --git a/lib/stripe_mock/api/operations/card.ex b/lib/stripe_mock/api/operations/card.ex
index 7c9a292..5e0a136 100644
--- a/lib/stripe_mock/api/operations/card.ex
+++ b/lib/stripe_mock/api/operations/card.ex
@@ -1,26 +1,38 @@
 defmodule StripeMock.API.Operations.Card do
+  import Ecto.Query
+  alias Ecto.Multi
   alias StripeMock.Repo
-  alias StripeMock.API.Card
+  alias StripeMock.API.{Card, Source}
 
   def list_cards(customer) do
     Card
+    |> where([c], not c.deleted)
+    |> where([c], c.customer_id == ^customer.id)
     |> Repo.all()
-    |> Enum.filter(&(&1.customer_id == customer.id))
   end
 
   def get_card(id), do: Repo.fetch(Card, id)
   def get_card!(id), do: Repo.get!(Card, id)
 
   def create_card(customer, attrs) do
-    %Card{customer_id: customer.id}
-    |> Card.create_changeset(attrs)
-    |> Repo.insert()
+    Multi.new()
+    |> Multi.insert(:card, Card.create_changeset(%Card{customer_id: customer.id}, attrs))
+    |> Multi.run(:source, fn _repo, %{card: card} ->
+      %Source{}
+      |> Source.changeset(%{card_id: card.id})
+      |> Repo.insert()
+    end)
+    |> Repo.transaction()
+    |> case do
+      {:ok, %{card: card}} -> {:ok, card}
+      {:error, _, value, _} -> {:error, value}
+    end
   end
 
   def create_customer_card_from_source(customer, source, metadata) do
     result =
       source.card
-      |> Ecto.Changeset.change(%{customer_id: customer.id, metadata: metadata})
+      |> Ecto.Changeset.change(%{customer_id: customer.id, metadata: metadata || %{}})
       |> Repo.update()
 
     source
diff --git a/lib/stripe_mock/api/operations/charge.ex b/lib/stripe_mock/api/operations/charge.ex
index 18faa66..3767c27 100644
--- a/lib/stripe_mock/api/operations/charge.ex
+++ b/lib/stripe_mock/api/operations/charge.ex
@@ -1,6 +1,6 @@
 defmodule StripeMock.API.Operations.Charge do
   alias StripeMock.Repo
-  alias StripeMock.API.{Card, Charge, Token}
+  alias StripeMock.API.Charge
 
   def list_charges() do
     Charge
@@ -14,20 +14,6 @@ defmodule StripeMock.API.Operations.Charge do
     end
   end
 
-  defp preload_source(charges) when is_list(charges) do
-    Enum.map(charges, &preload_source/1)
-  end
-
-  defp preload_source({:ok, charge}) do
-    {:ok, preload_source(charge)}
-  end
-
-  defp preload_source(%Charge{} = charge) do
-    %{charge | source: fetch_source(charge.source_id)}
-  end
-
-  defp preload_source(any), do: any
-
   def create_charge(attrs \\ %{}) do
     %Charge{}
     |> Charge.create_changeset(attrs)
@@ -37,19 +23,22 @@ defmodule StripeMock.API.Operations.Charge do
 
   def update_charge(%Charge{} = charge, attrs) do
     charge
-    |> Charge.create_changeset(attrs)
+    |> Charge.update_changeset(attrs)
     |> Repo.update()
     |> preload_source()
   end
 
-  defp fetch_source("card_" <> _ = card_id), do: Repo.get(Card, card_id)
+  defp preload_source({:ok, charge}) do
+    {:ok, preload_source(charge)}
+  end
 
-  defp fetch_source("tok_" <> _ = token_id) do
-    case Repo.get(Token, token_id) do
-      %{card_id: card_id} -> fetch_source(card_id)
-      _ -> nil
-    end
+  defp preload_source(%Charge{} = charge) do
+    Repo.preload(charge, [:card, :token])
+  end
+
+  defp preload_source([_ | _] = charges) do
+    Repo.preload(charges, [:card, :token])
   end
 
-  defp fetch_source(nil), do: nil
+  defp preload_source(arg), do: arg
 end
diff --git a/lib/stripe_mock/api/operations/token.ex b/lib/stripe_mock/api/operations/token.ex
index 52ea324..f12e1ca 100644
--- a/lib/stripe_mock/api/operations/token.ex
+++ b/lib/stripe_mock/api/operations/token.ex
@@ -1,14 +1,28 @@
 defmodule StripeMock.API.Operations.Token do
+  import Ecto.Query
+
+  alias Ecto.Multi
   alias StripeMock.Repo
-  alias StripeMock.API.Token
+  alias StripeMock.API.{Token, Source}
 
   def get_token(id) do
-    Repo.fetch(Token, id)
+    Token
+    |> preload(:card)
+    |> Repo.fetch(id)
   end
 
   def create_token(attrs) do
-    %Token{}
-    |> Token.changeset(attrs)
-    |> Repo.insert()
+    Multi.new()
+    |> Multi.insert(:token, Token.changeset(%Token{}, attrs))
+    |> Multi.run(:source, fn _repo, %{token: token} ->
+      %Source{}
+      |> Source.changeset(%{token_id: token.id})
+      |> Repo.insert()
+    end)
+    |> Repo.transaction()
+    |> case do
+      {:ok, %{token: token}} -> {:ok, token}
+      {:error, _, value, _} -> {:error, value}
+    end
   end
 end
diff --git a/lib/stripe_mock/api/refund.ex b/lib/stripe_mock/api/refund.ex
index 8aa5d7f..5ff58bf 100644
--- a/lib/stripe_mock/api/refund.ex
+++ b/lib/stripe_mock/api/refund.ex
@@ -2,14 +2,14 @@ defmodule StripeMock.API.Refund do
   use StripeMock.Schema
   alias StripeMock.Repo
 
-  @foreign_key_type :binary_id
   schema "refunds" do
     field :amount, :integer
-    field :created, :integer
-    field :metadata, StripeMock.Type.Metadata, default: %{}
+    field :metadata, :map, default: %{}
     field :reason, :string
 
     belongs_to :charge, API.Charge
+
+    timestamps()
   end
 
   @doc false
diff --git a/lib/stripe_mock/api/source.ex b/lib/stripe_mock/api/source.ex
new file mode 100644
index 0000000..dffbd2d
--- /dev/null
+++ b/lib/stripe_mock/api/source.ex
@@ -0,0 +1,14 @@
+defmodule StripeMock.API.Source do
+  use StripeMock.Schema
+
+  schema "sources" do
+    belongs_to :card, API.Card
+    belongs_to :token, API.Card
+  end
+
+  @doc false
+  def changeset(token, attrs) do
+    token
+    |> cast(attrs, [:card_id, :token_id])
+  end
+end
diff --git a/lib/stripe_mock/api/token.ex b/lib/stripe_mock/api/token.ex
index f37e7c3..a3cced2 100644
--- a/lib/stripe_mock/api/token.ex
+++ b/lib/stripe_mock/api/token.ex
@@ -1,14 +1,14 @@
 defmodule StripeMock.API.Token do
   use StripeMock.Schema
 
-  @foreign_key_type :binary_id
   schema "tokens" do
     field :client_ip, :string
-    field :created, :integer
     field :type, :string
     field :used, :boolean, default: false
 
     belongs_to :card, API.Card
+
+    timestamps()
   end
 
   @doc false
diff --git a/lib/stripe_mock/repo.ex b/lib/stripe_mock/repo.ex
index 843d2d9..187555f 100644
--- a/lib/stripe_mock/repo.ex
+++ b/lib/stripe_mock/repo.ex
@@ -1,172 +1,31 @@
 defmodule StripeMock.Repo do
-  @moduledoc """
-  This is where we store everything. Obviously, don't call any of these
-  functions yourself.
-
-  State structure is:
-
-      %{
-        customer: %{
-          "cus_123123" => %Customer{}
-        }
-      }
-  """
-  use GenServer
+  use Ecto.Repo, otp_app: :stripe_mock, adapter: Ecto.Adapters.Postgres
   import Ecto.Changeset
   alias Ecto.Changeset
   alias StripeMock.API
 
-  def start_link(opts \\ []) do
-    GenServer.start_link(__MODULE__, %{}, [name: __MODULE__] ++ opts)
-  end
-
-  def all(schema), do: GenServer.call(pid(), {:all, schema})
-  def insert(changeset), do: GenServer.call(pid(), {:save, changeset})
-  def update(changeset), do: GenServer.call(pid(), {:save, changeset})
-  def get(schema, id), do: GenServer.call(pid(), {:get, schema, id})
-
-  def get!(schema, id) do
-    case GenServer.call(pid(), {:get, schema, id}) do
-      nil ->
-        raise Ecto.NoResultsError, message: "No #{schema} found with id #{id}.", queryable: schema
-
-      record ->
-        record
-    end
-  end
-
   def fetch(schema, id) do
-    case get(schema, id) do
-      nil -> {:error, :not_found}
-      object -> {:ok, object}
-    end
-  end
-
-  def delete(%Changeset{} = changeset) do
-    changeset = put_change(changeset, :deleted, true)
-    GenServer.call(pid(), {:save, changeset})
-  end
-
-  def delete(object), do: GenServer.call(pid(), {:save, %{object | deleted: true}})
-
-  defp pid(), do: GenServer.whereis(__MODULE__)
-
-  @impl true
-  def init(state) do
-    {:ok, state}
-  end
-
-  @impl true
-  def handle_call({:all, schema}, _from, state) do
-    with schemas when is_map(schemas) <- Map.get(state, type(schema)),
-         objects <- Map.values(schemas),
-         not_deleted <-
-           Enum.filter(objects, fn
-             %{deleted: true} -> false
-             _ -> true
-           end) do
-      {:reply, not_deleted, state}
+    with true <- valid_id?(id),
+         %{} = object <- get(schema, id) do
+      {:ok, object}
     else
-      _ -> {:reply, [], state}
+      _ -> {:error, :not_found}
     end
   end
 
-  @impl true
-  def handle_call({:save, changeset}, _from, state) do
-    case save(changeset, state) do
-      {:ok, term, new_state} -> {:reply, {:ok, term}, new_state}
-      {:error, _} = error -> {:reply, error, state}
+  defp valid_id?(id) do
+    case Ecto.UUID.cast(id) do
+      {:ok, _} -> true
+      _ -> false
     end
   end
 
-  @impl true
-  def handle_call({:get, schema, id}, _from, state) do
-    object =
-      with schemas when is_map(schemas) <- Map.get(state, type(schema)),
-           object when is_map(object) <- Map.get(schemas, id) do
-        object
-      else
-        _ -> nil
-      end
-
-    {:reply, object, state}
-  end
-
-  @spec save(Changeset.t(), map()) :: {:ok, any(), map()} | {:error, Changeset.t()}
-  defp save(changeset, state) do
-    changeset = change(changeset)
-
-    changeset =
-      case get_field(changeset, :id) do
-        nil -> put_change(changeset, :id, generate_id(changeset.data))
-        id when is_bitstring(id) -> changeset
-      end
-
-    changeset =
-      cond do
-        Map.has_key?(changeset.data, :created) ->
-          case get_field(changeset, :created) do
-            nil -> put_change(changeset, :created, :os.system_time(:seconds))
-            _ -> changeset
-          end
-
-        true ->
-          changeset
-      end
-
-    changeset =
-      if Map.has_key?(changeset.data, :object) do
-        put_change(changeset, :object, type(changeset.data))
-      else
-        changeset
-      end
-
-    changeset = set_client_ip(changeset)
-
-    # Run through changed assocs and save
-    {changeset, state} =
-      Enum.reduce_while(changeset.changes, {changeset, state}, fn
-        {key, %Changeset{} = assoc_change}, {changeset, state} ->
-          case save(assoc_change, state) do
-            {:ok, saved_assoc, new_state} ->
-              changeset =
-                changeset
-                |> put_change(key, saved_assoc)
-                |> put_change(String.to_atom("#{key}_id"), saved_assoc.id)
-
-              {:cont, {changeset, new_state}}
-
-            {:error, failed_assoc} ->
-              changeset = put_change(changeset, key, failed_assoc)
-              throw({:invalid_changeset, changeset})
-          end
-
-        _, acc ->
-          {:cont, acc}
-      end)
-
-    if !changeset.valid? do
-      throw({:invalid_changeset, changeset})
-    end
-
-    object = apply_changes(changeset)
-
-    # Put the object into the new state
-    type = type(object)
-
-    type_map =
-      case Map.get(state, type) do
-        %{} = s -> s
-        _ -> %{}
-      end
-      |> Map.put(object.id, object)
-
-    new_state = Map.put(state, type, type_map)
+  defoverridable delete: 1, delete: 2
 
-    {:ok, object, new_state}
-  catch
-    {:invalid_changeset, changeset} ->
-      {:error, changeset}
+  def delete(struct) do
+    struct
+    |> change(%{deleted: true})
+    |> update()
   end
 
   if Mix.env() == :test do
diff --git a/lib/stripe_mock/schema.ex b/lib/stripe_mock/schema.ex
index aec9302..e232b1c 100644
--- a/lib/stripe_mock/schema.ex
+++ b/lib/stripe_mock/schema.ex
@@ -3,7 +3,22 @@ defmodule StripeMock.Schema do
     quote do
       use Ecto.Schema
       import Ecto.Changeset, warn: false
-      alias StripeMock.API
+      import Ecto.Query
+      import unquote(__MODULE__)
+      alias StripeMock.{API, Repo}
+
+      Module.put_attribute(__MODULE__, :primary_key, {:id, :binary_id, autogenerate: true})
+      Module.put_attribute(__MODULE__, :foreign_key_type, :binary_id)
+      Module.put_attribute(__MODULE__, :timestamps_opts, inserted_at: :created, updated_at: false)
+    end
+  end
+
+  import Ecto.Changeset
+
+  def put_common_fields(changeset) do
+    case get_field(changeset, :metadata) do
+      nil -> put_change(changeset, :metadata, %{})
+      _ -> changeset
     end
   end
 end
diff --git a/lib/stripe_mock/type/metadata.ex b/lib/stripe_mock/type/metadata.ex
deleted file mode 100644
index a903918..0000000
--- a/lib/stripe_mock/type/metadata.ex
+++ /dev/null
@@ -1,27 +0,0 @@
-defmodule StripeMock.Type.Metadata do
-  @behaviour Ecto.Type
-
-  def type(), do: :map
-
-  def cast(nil), do: {:ok, %{}}
-  def cast(""), do: {:ok, %{}}
-
-  def cast(metadata) when is_map(metadata) do
-    value =
-      for {k, v} <- metadata,
-          is_bitstring(k) and String.length(k) <= 40,
-          is_bitstring(v) and String.length(v) <= 500,
-          into: %{},
-          do: {k, v}
-
-    {:ok, value}
-  end
-
-  def cast(_), do: :error
-
-  def dump(value) when is_map(value), do: {:ok, value}
-  def dump(_), do: :error
-
-  def load(value) when is_map(value), do: {:ok, value}
-  def load(_), do: :error
-end
diff --git a/lib/stripe_mock_web.ex b/lib/stripe_mock_web.ex
index 5e90271..7276f33 100644
--- a/lib/stripe_mock_web.ex
+++ b/lib/stripe_mock_web.ex
@@ -44,6 +44,7 @@ defmodule StripeMockWeb do
       import StripeMockWeb.ViewHelpers
       import StripeMockWeb.Gettext
       alias StripeMockWeb.Router.Helpers, as: Routes
+      alias StripeMock.API
     end
   end
 
diff --git a/lib/stripe_mock_web/controllers/charge_controller.ex b/lib/stripe_mock_web/controllers/charge_controller.ex
index 9de5c85..9fb07a6 100644
--- a/lib/stripe_mock_web/controllers/charge_controller.ex
+++ b/lib/stripe_mock_web/controllers/charge_controller.ex
@@ -4,8 +4,7 @@ defmodule StripeMockWeb.ChargeController do
   alias StripeMock.API
   alias StripeMock.API.Charge
 
-  plug SMPlug.ConvertParams,
-       %{"customer" => "customer_id", "source" => "source_id"} when action in [:create, :update]
+  plug SMPlug.ConvertParams, %{"customer" => "customer_id"} when action in [:create, :update]
 
   action_fallback StripeMockWeb.FallbackController
 
diff --git a/lib/stripe_mock_web/view_helpers.ex b/lib/stripe_mock_web/view_helpers.ex
index 5ed8ff7..236c4d5 100644
--- a/lib/stripe_mock_web/view_helpers.ex
+++ b/lib/stripe_mock_web/view_helpers.ex
@@ -1,7 +1,21 @@
 defmodule StripeMockWeb.ViewHelpers do
   def as_map(struct) do
     struct
+    |> update_created()
     |> Map.delete(:__struct__)
     |> Map.delete(:__meta__)
   end
+
+  defp update_created(%{created: %{} = timestamp} = struct) do
+    created =
+      timestamp
+      |> NaiveDateTime.to_erl()
+      |> :calendar.datetime_to_gregorian_seconds()
+
+    %{struct | created: created}
+  end
+
+  defp update_created(struct) do
+    struct
+  end
 end
diff --git a/lib/stripe_mock_web/views/card_view.ex b/lib/stripe_mock_web/views/card_view.ex
index da8578c..dfcfe01 100644
--- a/lib/stripe_mock_web/views/card_view.ex
+++ b/lib/stripe_mock_web/views/card_view.ex
@@ -15,6 +15,7 @@ defmodule StripeMockWeb.CardView do
     |> Map.take(~w(id created deleted exp_month exp_year metadata last4 brand)a)
     |> Map.put("object", "card")
     |> Map.put("customer", card.customer_id)
+    |> as_map()
   end
 
   def render("delete.json", %{card: card}) do
diff --git a/lib/stripe_mock_web/views/charge_view.ex b/lib/stripe_mock_web/views/charge_view.ex
index 92826f3..705ce20 100644
--- a/lib/stripe_mock_web/views/charge_view.ex
+++ b/lib/stripe_mock_web/views/charge_view.ex
@@ -21,10 +21,11 @@ defmodule StripeMockWeb.ChargeView do
       metadata: charge.metadata,
       object: "charge",
       outcome: render_outcome(charge),
-      source: render(StripeMockWeb.CardView, "card.json", card: charge.source),
+      payment_method: render(StripeMockWeb.CardView, "card.json", card: charge.card),
       statement_descriptor: charge.statement_descriptor,
       transfer_group: charge.transfer_group
     }
+    |> as_map()
   end
 
   defp render_outcome(_charge) do
diff --git a/lib/stripe_mock_web/views/source_view.ex b/lib/stripe_mock_web/views/source_view.ex
index e0a607b..cb2e5e5 100644
--- a/lib/stripe_mock_web/views/source_view.ex
+++ b/lib/stripe_mock_web/views/source_view.ex
@@ -2,9 +2,6 @@ defmodule StripeMockWeb.SourceView do
   use StripeMockWeb, :view
 
   def render("show.json", %{source: source}) do
-    case source.id do
-      "card_" <> _ -> render_one(source, StripeMockWeb.CardView, "card.json")
-      _ -> raise "Weird ID"
-    end
+    render_one(source, StripeMockWeb.CardView, "card.json")
   end
 end
diff --git a/lib/stripe_mock_web/views/token_view.ex b/lib/stripe_mock_web/views/token_view.ex
index 8df98ce..24cf890 100644
--- a/lib/stripe_mock_web/views/token_view.ex
+++ b/lib/stripe_mock_web/views/token_view.ex
@@ -26,5 +26,6 @@ defmodule StripeMockWeb.TokenView do
     else
       object
     end
+    |> as_map()
   end
 end
diff --git a/mix.exs b/mix.exs
index 1e5da9a..025c135 100644
--- a/mix.exs
+++ b/mix.exs
@@ -10,6 +10,7 @@ defmodule StripeMock.MixProject do
       compilers: [:phoenix, :gettext] ++ Mix.compilers(),
       start_permanent: false,
       description: description(),
+      aliases: aliases(),
       package: package(),
       deps: deps()
     ]
@@ -51,11 +52,18 @@ defmodule StripeMock.MixProject do
   defp deps do
     [
       {:phoenix, ">= 0.0.0"},
+      {:phoenix_ecto, ">= 0.0.0"},
       {:gettext, "~> 0.11"},
       {:jason, "~> 1.0"},
       {:plug_cowboy, "~> 2.0"},
-      {:ecto, "~> 3.1"},
+      {:postgrex, ">= 0.0.0"},
+      {:ecto, "~> 3.2"},
+      {:ecto_sql, "~> 3.2"},
       {:ex_doc, ">= 0.0.0", only: :dev}
     ]
   end
+
+  defp aliases do
+    [test: ["ecto.migrate", "test"]]
+  end
 end
diff --git a/mix.lock b/mix.lock
index 10fc0e2..51e8ed2 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,9 +1,12 @@
 %{
+  "connection": {:hex, :connection, "1.0.4", "a1cae72211f0eef17705aaededacac3eb30e6625b04a6117c1b2db6ace7d5976", [:mix], [], "hexpm"},
   "cowboy": {:hex, :cowboy, "2.6.3", "99aa50e94e685557cad82e704457336a453d4abcb77839ad22dbe71f311fcc06", [:rebar3], [{:cowlib, "~> 2.7.3", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "~> 1.7.1", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm"},
   "cowlib": {:hex, :cowlib, "2.7.3", "a7ffcd0917e6d50b4d5fb28e9e2085a0ceb3c97dea310505f7460ff5ed764ce9", [:rebar3], [], "hexpm"},
-  "decimal": {:hex, :decimal, "1.7.0", "30d6b52c88541f9a66637359ddf85016df9eb266170d53105f02e4a67e00c5aa", [:mix], [], "hexpm"},
+  "db_connection": {:hex, :db_connection, "2.1.1", "a51e8a2ee54ef2ae6ec41a668c85787ed40cb8944928c191280fe34c15b76ae5", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}], "hexpm"},
+  "decimal": {:hex, :decimal, "1.8.0", "ca462e0d885f09a1c5a342dbd7c1dcf27ea63548c65a65e67334f4b61803822e", [:mix], [], "hexpm"},
   "earmark": {:hex, :earmark, "1.3.2", "b840562ea3d67795ffbb5bd88940b1bed0ed9fa32834915125ea7d02e35888a5", [:mix], [], "hexpm"},
-  "ecto": {:hex, :ecto, "3.1.4", "69d852da7a9f04ede725855a35ede48d158ca11a404fe94f8b2fb3b2162cd3c9", [:mix], [{:decimal, "~> 1.6", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}], "hexpm"},
+  "ecto": {:hex, :ecto, "3.2.2", "bb6d1dbcd7ef975b60637e63182e56f3d7d0b5dd9c46d4b9d6183a5c455d65d1", [:mix], [{:decimal, "~> 1.6", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}], "hexpm"},
+  "ecto_sql": {:hex, :ecto_sql, "3.2.0", "751cea597e8deb616084894dd75cbabfdbe7255ff01e8c058ca13f0353a3921b", [:mix], [{:db_connection, "~> 2.1", [hex: :db_connection, repo: "hexpm", optional: false]}, {:ecto, "~> 3.2.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:myxql, "~> 0.2.0", [hex: :myxql, repo: "hexpm", optional: true]}, {:postgrex, "~> 0.15.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm"},
   "ex_doc": {:hex, :ex_doc, "0.20.2", "1bd0dfb0304bade58beb77f20f21ee3558cc3c753743ae0ddbb0fd7ba2912331", [:mix], [{:earmark, "~> 1.3", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.10", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
   "gettext": {:hex, :gettext, "0.16.1", "e2130b25eebcbe02bb343b119a07ae2c7e28bd4b146c4a154da2ffb2b3507af2", [:mix], [], "hexpm"},
   "jason": {:hex, :jason, "1.1.2", "b03dedea67a99223a2eaf9f1264ce37154564de899fd3d8b9a21b1a6fd64afe7", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm"},
@@ -12,9 +15,12 @@
   "mime": {:hex, :mime, "1.3.1", "30ce04ab3175b6ad0bdce0035cba77bba68b813d523d1aac73d9781b4d193cf8", [:mix], [], "hexpm"},
   "nimble_parsec": {:hex, :nimble_parsec, "0.5.0", "90e2eca3d0266e5c53f8fbe0079694740b9c91b6747f2b7e3c5d21966bba8300", [:mix], [], "hexpm"},
   "phoenix": {:hex, :phoenix, "1.4.6", "8535f4a01291f0fbc2c30c78c4ca6a2eacc148db5178ad76e8b2fc976c590115", [: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_pubsub": {:hex, :phoenix_pubsub, "1.1.2", "496c303bdf1b2e98a9d26e89af5bba3ab487ba3a3735f74bf1f4064d2a845a3e", [:mix], [], "hexpm"},
   "plug": {:hex, :plug, "1.8.0", "9d2685cb007fe5e28ed9ac27af2815bc262b7817a00929ac10f56f169f43b977", [:mix], [{:mime, "~> 1.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: true]}], "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, "0.15.1", "23ce3417de70f4c0e9e7419ad85bdabcc6860a6925fe2c6f3b1b5b1e8e47bf2f", [:mix], [{:connection, "~> 1.0", [hex: :connection, repo: "hexpm", optional: false]}, {:db_connection, "~> 2.1", [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"},
+  "telemetry": {:hex, :telemetry, "0.4.0", "8339bee3fa8b91cb84d14c2935f8ecf399ccd87301ad6da6b71c09553834b2ab", [:rebar3], [], "hexpm"},
 }
diff --git a/priv/repo/migrations/20191015221147_create_tables.exs b/priv/repo/migrations/20191015221147_create_tables.exs
new file mode 100644
index 0000000..dabfa63
--- /dev/null
+++ b/priv/repo/migrations/20191015221147_create_tables.exs
@@ -0,0 +1,76 @@
+defmodule StripeMock.Repo.Migrations.CreateTables do
+  use Ecto.Migration
+
+  defmacro common_fields() do
+    quote do
+      add(:deleted, :boolean, null: false, default: false)
+      add(:description, :string)
+      add(:metadata, :map, null: false, default: %{})
+      timestamps(inserted_at: :created, updated_at: false)
+    end
+  end
+
+  def change do
+    create table(:customers) do
+      add(:currency, :string, default: "usd")
+      add(:email, :string)
+      add(:name, :string)
+      add(:phone, :string)
+
+      common_fields()
+    end
+
+    create table(:cards) do
+      add(:brand, :string)
+      add(:last4, :string)
+      add(:source, :string)
+
+      add(:number, :string)
+      add(:exp_month, :integer)
+      add(:exp_year, :integer)
+      add(:cvc, :string)
+
+      add(:customer_id, references(:customers))
+
+      common_fields()
+    end
+
+    create table(:tokens) do
+      add(:client_ip, :string)
+      add(:type, :string)
+      add(:used, :boolean, default: false)
+
+      add(:card_id, references(:cards))
+
+      common_fields()
+    end
+
+    create table(:sources) do
+      add(:card_id, references(:cards))
+      add(:token_id, references(:tokens))
+    end
+
+    create table(:charges) do
+      add(:amount, :integer)
+      add(:capture, :boolean, default: false)
+      add(:currency, :string)
+      add(:statement_descriptor, :string)
+      add(:transfer_group, :string)
+
+      add(:customer_id, references(:customers))
+      add(:card_id, references(:cards))
+      add(:token_id, references(:tokens))
+
+      common_fields()
+    end
+
+    create table(:refunds) do
+      add(:amount, :integer)
+      add(:reason, :string)
+
+      add(:charge_id, references(:charges))
+
+      common_fields()
+    end
+  end
+end
diff --git a/test/stripe_mock_web/controllers/charge_controller_test.exs b/test/stripe_mock_web/controllers/charge_controller_test.exs
index 7e79b31..eb77903 100644
--- a/test/stripe_mock_web/controllers/charge_controller_test.exs
+++ b/test/stripe_mock_web/controllers/charge_controller_test.exs
@@ -36,7 +36,7 @@ defmodule StripeMockWeb.ChargeControllerTest do
                "amount" => 5000,
                "capture" => true,
                "currency" => "some currency",
-               "customer" => "cus_" <> _,
+               "customer" => _,
                "description" => "some description",
                "metadata" => %{},
                "statement_descriptor" => "some statement_descriptor",
@@ -87,11 +87,6 @@ defmodule StripeMockWeb.ChargeControllerTest do
                "metadata" => %{"key" => "val"}
              } = json_response(conn, 200)
     end
-
-    test "renders errors when data is invalid", %{conn: conn, charge: charge} do
-      conn = put(conn, Routes.charge_path(conn, :update, charge), invalid_attrs())
-      assert json_response(conn, 422)["errors"] != %{}
-    end
   end
 
   def create_attrs() do
diff --git a/test/stripe_mock_web/controllers/refund_controller_test.exs b/test/stripe_mock_web/controllers/refund_controller_test.exs
index 835844a..d29daf0 100644
--- a/test/stripe_mock_web/controllers/refund_controller_test.exs
+++ b/test/stripe_mock_web/controllers/refund_controller_test.exs
@@ -16,21 +16,23 @@ defmodule StripeMockWeb.RefundControllerTest do
 
   describe "create refund" do
     test "renders refund when data is valid", %{conn: conn, charge: charge} do
+      charge_id = charge.id
       conn = post(conn, Routes.refund_path(conn, :create), create_attrs(charge.id))
       assert %{"id" => id} = json_response(conn, 201)
 
       conn = get(conn, Routes.refund_path(conn, :show, id))
 
       assert %{
-               "id" => "re_" <> _,
+               "id" => _,
                "amount" => 5000,
-               "charge" => "ch_" <> _,
+               "charge" => ^charge_id,
                "created" => _,
                "metadata" => %{}
              } = json_response(conn, 200)
     end
 
     test "amount defaults to full amount of the charge", %{conn: conn, charge: charge} do
+      charge_id = charge.id
       params = %{create_attrs(charge.id) | amount: nil}
       conn = post(conn, Routes.refund_path(conn, :create), params)
       amount = charge.amount
@@ -40,9 +42,9 @@ defmodule StripeMockWeb.RefundControllerTest do
       conn = get(conn, Routes.refund_path(conn, :show, id))
 
       assert %{
-               "id" => "re_" <> _,
+               "id" => _,
                "amount" => ^amount,
-               "charge" => "ch_" <> _,
+               "charge" => ^charge_id,
                "metadata" => %{}
              } = json_response(conn, 200)
     end
diff --git a/test/stripe_mock_web/controllers/source_controller_test.exs b/test/stripe_mock_web/controllers/source_controller_test.exs
index 1d7f200..8cd8a0f 100644
--- a/test/stripe_mock_web/controllers/source_controller_test.exs
+++ b/test/stripe_mock_web/controllers/source_controller_test.exs
@@ -40,7 +40,7 @@ defmodule StripeMockWeb.SourceControllerTest do
         |> post(Routes.customer_source_path(conn, :create, customer.id), source: token)
         |> json_response(201)
 
-      assert id =~ ~r/^card_/
+      assert id
     end
 
     test "renders errors when data is invalid", %{conn: conn, customer: customer} do
diff --git a/test/stripe_mock_web/controllers/token_controller_test.exs b/test/stripe_mock_web/controllers/token_controller_test.exs
index a38802a..ba85aee 100644
--- a/test/stripe_mock_web/controllers/token_controller_test.exs
+++ b/test/stripe_mock_web/controllers/token_controller_test.exs
@@ -12,13 +12,13 @@ defmodule StripeMockWeb.TokenControllerTest do
       conn = get(conn, Routes.token_path(conn, :show, id))
 
       assert %{
-               "id" => "tok_" <> _,
+               "id" => _,
                "client_ip" => "127.0.0.1",
                "created" => created,
                "object" => "token",
                "type" => "card",
                "used" => false,
-               "card" => %{"id" => "card_" <> _}
+               "card" => %{"id" => _}
              } = json_response(conn, 200)
 
       assert is_integer(created)
diff --git a/test/test_helper.exs b/test/test_helper.exs
index 984ed98..6ba4291 100644
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -37,7 +37,7 @@ defmodule StripeMock.TestHelper do
         customer_id: customer.id,
         description: "some description",
         metadata: %{},
-        source_id: token.id,
+        source: token.id,
         statement_descriptor: "some statement_descriptor",
         transfer_group: "some transfer_group"
       })