diff --git a/.formatter.exs b/.formatter.exs
index 8b1926c..f5932ff 100644
--- a/.formatter.exs
+++ b/.formatter.exs
@@ -1,4 +1,11 @@
-spark_locals_without_parens = [attribute: 2, attribute: 3, factory: 1, factory: 2, factory: 3]
+spark_locals_without_parens = [
+  api: 1,
+  attribute: 2,
+  attribute: 3,
+  factory: 1,
+  factory: 2,
+  factory: 3
+]
 
 [
   import_deps: [:ash, :spark],
diff --git a/lib/smokestack.ex b/lib/smokestack.ex
index e6fe6a6..b84d461 100644
--- a/lib/smokestack.ex
+++ b/lib/smokestack.ex
@@ -20,38 +20,40 @@ defmodule Smokestack do
 
   use Dsl, default_extensions: [extensions: [Smokestack.Dsl]]
   alias Ash.Resource
-  alias Smokestack.Builder
+  alias Smokestack.{ParamBuilder, RecordBuilder}
 
   @type t :: module
 
+  @type recursive_atom_list :: atom | [atom | {atom, recursive_atom_list()}]
+
   @doc """
   Runs a factory and uses it to build a map or list of results.
 
   Automatically implemented by modules which `use Smokestack`.
 
-  See `Smokestack.Builder.params/5` for more information.
+  See `Smokestack.ParamBuilder.build/2` for more information.
   """
-  @callback params(Resource.t(), map, atom, Builder.param_options()) ::
-              {:ok, Builder.param_result()} | {:error, any}
+  @callback params(Resource.t(), ParamBuilder.param_options()) ::
+              {:ok, ParamBuilder.param_result()} | {:error, any}
 
   @doc """
-  Raising version of `params/4`.
+  Raising version of `params/2`.
 
   Automatically implemented by modules which `use Smokestack`.
 
-  See `Smokestack.Builder.params/5` for more information.
+  See `Smokestack.ParamBuilder.build/3` for more information.
   """
-  @callback params!(Resource.t(), map, atom, Builder.param_options()) ::
-              Builder.param_result() | no_return
+  @callback params!(Resource.t(), ParamBuilder.param_options()) ::
+              ParamBuilder.param_result() | no_return
 
   @doc """
-  Runs a factory and uses it to insert an Ash Resource into it's data layer. 
+  Runs a factory and uses it to insert an Ash Resource into it's data layer.
 
   Automatically implemented by modules which `use Smokestack`.
 
-  See `Smokestack.Builder.insert/5` for more information.
+  See `Smokestack.RecordBuilder.build/3` for more information.
   """
-  @callback insert(Resource.t(), map, atom, Builder.insert_options()) ::
+  @callback insert(Resource.t(), RecordBuilder.insert_options()) ::
               {:ok, Resource.record()} | {:error, any}
 
   @doc """
@@ -59,31 +61,11 @@ defmodule Smokestack do
 
   Automatically implemented by modules which `use Smokestack`.
 
-  See `Smokestack.Builder.insert/5` for more information.
+  See `Smokestack.RecordBuilder.build/3` for more information.
   """
-  @callback insert!(Resource.t(), map, atom, Builder.insert_options()) ::
+  @callback insert!(Resource.t(), RecordBuilder.insert_options()) ::
               Resource.record() | no_return
 
-  @doc """
-  Runs a factory a number of times and returns a list of created records.
-
-  Automatically implemented by modules which `use Smokestack`.
-
-  See `Smokestack.Builder.insert_many/5` for more information.
-  """
-  @callback insert_many(Resource.t(), pos_integer, atom, Builder.insert_options()) ::
-              {:ok, [Resource.record()]} | {:error, any}
-
-  @doc """
-  Raising version of `insert_many/4`.
-
-  Automatically implemented by modules which `use Smokestack`.
-
-  See `Smokestack.Builder.insert_many/5` for more information.
-  """
-  @callback insert_many!(Resource.t(), pos_integer, atom, Builder.insert_options()) ::
-              [Resource.record()] | no_return
-
   @doc false
   defmacro __using__(opts) do
     [
@@ -93,69 +75,47 @@ defmodule Smokestack do
         @doc """
         Execute the matching factory and return a map or list of params.
 
-        See `Smokestack.Builder.params/5` for more information.
+        See `Smokestack.ParamBuilder.build/3` for more information.
         """
-        @spec params(Resource.t(), map, atom, Builder.param_options()) ::
-                {:ok, Builder.param_result()} | {:error, any}
-        def params(resource, overrides \\ %{}, variant \\ :default, options \\ []),
-          do: Builder.params(__MODULE__, resource, overrides, variant, options)
+        @spec params(Resource.t(), ParamBuilder.param_options()) ::
+                {:ok, ParamBuilder.param_result()} | {:error, any}
+        def params(resource, options \\ []),
+          do: ParamBuilder.build(__MODULE__, resource, options)
 
         @doc """
-        Raising version of `params/4`.
+        Raising version of `params/2`.
 
-        See `Smokestack.Builder.params/5` for more information.
+        See `Smokestack.ParamBuilder.build/3` for more information.
         """
-        @spec params!(Resource.t(), map, atom, Builder.param_options()) ::
-                Builder.param_result() | no_return
-        def params!(resource, overrides \\ %{}, variant \\ :default, options \\ []),
-          do: Builder.params!(__MODULE__, resource, overrides, variant, options)
+        @spec params!(Resource.t(), ParamBuilder.param_options()) ::
+                ParamBuilder.param_result() | no_return
+        def params!(resource, options \\ []),
+          do: ParamBuilder.build!(__MODULE__, resource, options)
 
         @doc """
         Execute the matching factory and return an inserted Ash Resource record.
 
-        See `Smokestack.Builder.insert/5` for more information.
+        See `Smokestack.RecordBuilder.build/3` for more information.
         """
-        @spec insert(Resource.t(), map, atom, Builder.insert_options()) ::
+        @spec insert(Resource.t(), RecordBuilder.insert_options()) ::
                 {:ok, Resource.record()} | {:error, any}
-        def insert(resource, overrides \\ %{}, variant \\ :default, options \\ []),
-          do: Builder.insert(__MODULE__, resource, overrides, variant, options)
+        def insert(resource, options \\ []),
+          do: RecordBuilder.build(__MODULE__, resource, options)
 
         @doc """
-        Raising version of `insert/4`.
+        Raising version of `insert/2`.
 
-        See `Smokestack.Builder.insert/5` for more information.
+        See `Smokestack.RecordBuilder.build/3` for more information.
         """
-        @spec insert!(Resource.t(), map, atom, Builder.insert_options()) ::
+        @spec insert!(Resource.t(), RecordBuilder.insert_options()) ::
                 Resource.record() | no_return
-        def insert!(resource, overrides \\ %{}, variant \\ :default, options \\ []),
-          do: Builder.insert!(__MODULE__, resource, overrides, variant, options)
+        def insert!(resource, options \\ []),
+          do: RecordBuilder.build!(__MODULE__, resource, options)
 
-        @doc """
-        Execute the matching factory a number of times and return a list of Ash Resource records.
-
-        See `Smokestack.Builder.insert_many/5` for more information.
-        """
-        @spec insert_many(Resource.t(), pos_integer, atom, Builder.insert_options()) ::
-                {:ok, [Resource.record()]} | {:error, any}
-        def insert_many(resource, count, variant \\ :default, options \\ []),
-          do: Builder.insert_many(__MODULE__, resource, count, variant, options)
-
-        @doc """
-        Raising version of `insert_many/4`.
-
-        See `Smokestack.Builder.insert_many/5` for more information.
-        """
-        @spec insert_many!(Resource.t(), pos_integer, atom, Builder.insert_options()) ::
-                [Resource.record()] | no_return
-        def insert_many!(resource, count, variant \\ :default, options \\ []),
-          do: Builder.insert_many!(__MODULE__, resource, count, variant, options)
-
-        defoverridable params: 4,
-                       params!: 4,
-                       insert: 4,
-                       insert!: 4,
-                       insert_many: 4,
-                       insert_many!: 4
+        defoverridable params: 2,
+                       params!: 2,
+                       insert: 2,
+                       insert!: 2
       end
     ] ++ super(opts)
   end
diff --git a/lib/smokestack/builder.ex b/lib/smokestack/builder.ex
deleted file mode 100644
index 1d704e2..0000000
--- a/lib/smokestack/builder.ex
+++ /dev/null
@@ -1,216 +0,0 @@
-defmodule Smokestack.Builder do
-  @moduledoc """
-  Handles the building of parameters and records.
-  """
-
-  alias Ash.{Resource, Seed}
-  alias Smokestack.{Dsl.Attribute, Dsl.Info, Template}
-
-  @param_option_defaults [keys: :atom, as: :map]
-
-  @typedoc "Options that can be passed to `params/4`."
-  @type param_options :: [param_keys_option | param_as_option | build_option]
-
-  @typedoc "Key type in the result. Defaults to `#{inspect(@param_option_defaults[:keys])}`."
-  @type param_keys_option :: {:keys, :atom | :string | :dasherise}
-
-  @typedoc "Result type. Defaults to `#{inspect(@param_option_defaults[:as])}`"
-  @type param_as_option :: {:as, :map | :list}
-
-  @type param_result ::
-          %{required(atom | String.t()) => any}
-          | [{atom | String.t(), any}]
-
-  @type insert_options :: [build_option]
-
-  @typedoc "A nested keyword list of associations that should also be built"
-  @type build_option :: {:build, Keyword.t(atom | Keyword.t())}
-
-  @type insert_result :: Resource.record()
-
-  @doc """
-  Build parameters for a resource with a factory.
-  """
-  @spec params(Smokestack.t(), Resource.t(), map, atom, param_options) ::
-          {:ok, param_result} | {:error, any}
-  def params(factory_module, resource, overrides \\ %{}, variant \\ :default, options \\ [])
-      when is_atom(factory_module) and is_atom(resource) and is_atom(variant) and is_list(options) do
-    with {:ok, factory} <- get_factory(factory_module, resource, variant),
-         {:ok, params} <- build_params(factory, overrides, options) do
-      params =
-        params
-        |> maybe_stringify_keys(options)
-        |> maybe_dasherise_keys(options)
-        |> maybe_listify_result(options)
-
-      {:ok, params}
-    end
-  end
-
-  @doc "Raising version of `params/2..5`."
-  @spec params!(Smokestack.t(), Resource.t(), map, atom, param_options) ::
-          param_result | no_return
-  def params!(factory_module, resource, overrides \\ %{}, variant \\ :default, options \\ []) do
-    case params(factory_module, resource, overrides, variant, options) do
-      {:ok, params} -> params
-      {:error, reason} -> raise reason
-    end
-  end
-
-  @doc """
-  Build a resource and insert it into it's datalayer.
-  """
-  @spec insert(Smokestack.t(), Resource.t(), map, atom, insert_options) ::
-          {:ok, insert_result} | {:error, any}
-  def insert(factory_module, resource, overrides \\ %{}, variant \\ :default, options \\ [])
-      when is_atom(factory_module) and is_atom(resource) and is_atom(Variant) and is_list(options) do
-    with {:ok, factory} <- get_factory(factory_module, resource, variant),
-         {:ok, params} <- build_params(factory, overrides, options) do
-      record =
-        resource
-        |> Seed.seed!(params)
-        |> Resource.put_metadata(:factory, factory_module)
-        |> Resource.put_metadata(:variant, variant)
-
-      {:ok, record}
-    end
-  rescue
-    error -> {:error, error}
-  end
-
-  @doc "Raising version of `insert/2..5`"
-  @spec insert!(Smokestack.t(), Resource.t(), map, atom, insert_options) ::
-          insert_result | no_return
-  def insert!(factory_module, resource, overrides \\ %{}, variant \\ :default, options \\ [])
-      when is_atom(factory_module) and is_atom(resource) and is_atom(variant) and
-             is_map(overrides) and is_list(options) do
-    with {:ok, factory} <- get_factory(factory_module, resource, variant),
-         {:ok, params} <- build_params(factory, overrides, options) do
-      resource
-      |> Seed.seed!(params)
-      |> Resource.put_metadata(:factory, factory_module)
-      |> Resource.put_metadata(:variant, variant)
-    else
-      {:error, reason} -> raise reason
-    end
-  end
-
-  @doc """
-  Build a number of resources and insert them into their datalayer.
-  """
-  @spec insert_many(Smokestack.t(), Resource.t(), pos_integer, atom, insert_options) ::
-          {:ok, [insert_result]} | {:error, any}
-  def insert_many(factory_module, resource, count, variant \\ :default, options \\ [])
-      when is_atom(factory_module) and is_atom(resource) and is_integer(count) and count > 0 and
-             is_atom(variant) and is_list(options) do
-    with {:ok, factory} <- get_factory(factory_module, resource, variant),
-         {:ok, params_list} <- build_many_params(factory, count, options) do
-      records =
-        resource
-        |> Seed.seed!(params_list)
-        |> Enum.map(fn record ->
-          record
-          |> Resource.put_metadata(:factory, factory_module)
-          |> Resource.put_metadata(:variant, variant)
-        end)
-
-      {:ok, records}
-    end
-  rescue
-    error -> {:error, error}
-  end
-
-  @doc "Raising version of `insert_many/5`."
-  @spec insert_many!(Smokestack.t(), Resource.t(), pos_integer, atom, insert_options) ::
-          [insert_result] | no_return
-  def insert_many!(factory_module, resource, count, variant \\ :default, options \\ [])
-      when is_atom(factory_module) and is_atom(resource) and is_integer(count) and count > 0 and
-             is_atom(variant) and is_list(options) do
-    with {:ok, factory} <- get_factory(factory_module, resource, variant),
-         {:ok, params_list} <- build_many_params(factory, count, options) do
-      resource
-      |> Seed.seed!(params_list)
-      |> Enum.map(fn record ->
-        record
-        |> Resource.put_metadata(:factory, factory_module)
-        |> Resource.put_metadata(:variant, variant)
-      end)
-    else
-      {:error, reason} -> raise reason
-    end
-  end
-
-  defp build_many_params(factory, count, options) do
-    Enum.reduce_while(1..count, {:ok, []}, fn _, {:ok, params_list} ->
-      case build_params(factory, %{}, options) do
-        {:ok, params} -> {:cont, {:ok, [params | params_list]}}
-        {:error, reason} -> {:halt, {:error, reason}}
-      end
-    end)
-  end
-
-  defp get_factory(factory_module, resource, variant) do
-    with :error <- Info.factory(factory_module, resource, variant) do
-      {:error,
-       ArgumentError.exception(
-         message: "Factory for `#{inspect(resource)}` variant `#{inspect(variant)}` not found."
-       )}
-    end
-  end
-
-  defp build_params(factory, overrides, options) do
-    factory
-    |> Map.get(:attributes, [])
-    |> Enum.filter(&is_struct(&1, Attribute))
-    |> Enum.reduce({:ok, %{}}, fn attr, {:ok, attrs} ->
-      case Map.fetch(overrides, attr.name) do
-        {:ok, override} ->
-          {:ok, Map.put(attrs, attr.name, override)}
-
-        :error ->
-          generator = maybe_initialise_generator(attr)
-          value = Template.generate(generator, attrs, options)
-          {:ok, Map.put(attrs, attr.name, value)}
-      end
-    end)
-  end
-
-  defp maybe_initialise_generator(attr) do
-    with nil <- Process.get(attr.__identifier__),
-         generator <- Template.init(attr.generator) do
-      Process.put(attr.__identifier__, generator)
-      generator
-    end
-  end
-
-  defp maybe_stringify_keys(attrs, options) do
-    if Keyword.get(options, :keys, @param_option_defaults[:keys]) == :string do
-      Map.new(attrs, fn {key, value} -> {Atom.to_string(key), value} end)
-    else
-      attrs
-    end
-  end
-
-  defp maybe_dasherise_keys(attrs, options) do
-    if Keyword.get(options, :keys, @param_option_defaults[:keys]) == :dasherise do
-      Map.new(attrs, fn {key, value} ->
-        key =
-          key
-          |> Atom.to_string()
-          |> String.replace("_", "-")
-
-        {key, value}
-      end)
-    else
-      attrs
-    end
-  end
-
-  defp maybe_listify_result(attrs, options) do
-    if Keyword.get(options, :as, @param_option_defaults[:as]) == :list do
-      Enum.to_list(attrs)
-    else
-      attrs
-    end
-  end
-end
diff --git a/lib/smokestack/dsl.ex b/lib/smokestack/dsl.ex
index 5ecdcfe..a07da2a 100644
--- a/lib/smokestack/dsl.ex
+++ b/lib/smokestack/dsl.ex
@@ -5,7 +5,14 @@ defmodule Smokestack.Dsl do
   @section %Section{
     name: :smokestack,
     top_level?: true,
-    entities: Factory.__entities__()
+    entities: Factory.__entities__(),
+    schema: [
+      api: [
+        type: {:behaviour, Ash.Api},
+        required: false,
+        doc: "The default Ash API to use when evaluating loads"
+      ]
+    ]
   }
 
   @moduledoc """
diff --git a/lib/smokestack/dsl/factory.ex b/lib/smokestack/dsl/factory.ex
index 97305d1..0d1a85e 100644
--- a/lib/smokestack/dsl/factory.ex
+++ b/lib/smokestack/dsl/factory.ex
@@ -5,7 +5,12 @@ defmodule Smokestack.Dsl.Factory do
   See `d:Smokestack.factory` for more information.
   """
 
-  defstruct __identifier__: nil, attributes: [], resource: nil, variant: :default
+  defstruct __identifier__: nil,
+            api: nil,
+            attributes: [],
+            module: nil,
+            resource: nil,
+            variant: :default
 
   alias Ash.Resource
   alias Smokestack.Dsl.{Attribute, Template}
@@ -13,8 +18,10 @@ defmodule Smokestack.Dsl.Factory do
 
   @type t :: %__MODULE__{
           __identifier__: any,
+          api: nil,
           attributes: [Attribute.t()],
           resource: Resource.t(),
+          module: module,
           variant: atom
         }
 
@@ -30,6 +37,11 @@ defmodule Smokestack.Dsl.Factory do
         imports: [Template],
         identifier: {:auto, :unique_integer},
         schema: [
+          api: [
+            type: {:behaviour, Ash.Api},
+            required: false,
+            doc: "The Ash API to use when evaluating loads"
+          ],
           resource: [
             type: {:behaviour, Ash.Resource},
             required: true,
diff --git a/lib/smokestack/dsl/info.ex b/lib/smokestack/dsl/info.ex
index aa50bc5..e65e6c4 100644
--- a/lib/smokestack/dsl/info.ex
+++ b/lib/smokestack/dsl/info.ex
@@ -10,14 +10,20 @@ defmodule Smokestack.Dsl.Info do
   @doc """
   Retrieve a variant for a specific resource.
   """
-  @spec factory(Smokestack.t(), Resource.t(), atom) :: {:ok, Factory.t()} | :error
+  @spec factory(Smokestack.t(), Resource.t(), atom) :: {:ok, Factory.t()} | {:error, any}
   def factory(factory, resource, variant) do
     factory
     |> Extension.get_entities([:smokestack])
     |> Enum.find(&(is_struct(&1, Factory) && &1.resource == resource && &1.variant == variant))
     |> case do
-      nil -> :error
-      factory -> {:ok, factory}
+      nil ->
+        {:error,
+         ArgumentError.exception(
+           message: "Factory for `#{inspect(resource)}` variant `#{inspect(variant)}` not found."
+         )}
+
+      factory ->
+        {:ok, factory}
     end
   end
 end
diff --git a/lib/smokestack/dsl/transformer.ex b/lib/smokestack/dsl/transformer.ex
index 0093f5f..a3a5f8f 100644
--- a/lib/smokestack/dsl/transformer.ex
+++ b/lib/smokestack/dsl/transformer.ex
@@ -1,12 +1,35 @@
 defmodule Smokestack.Dsl.Transformer do
   @moduledoc false
 
+  alias Smokestack.Dsl.Factory
   alias Spark.{Dsl, Dsl.Transformer, Error.DslError}
   use Transformer
 
   @doc false
   @spec transform(Dsl.t()) :: {:ok, Dsl.t()} | {:error, DslError.t()}
   def transform(dsl_state) do
+    module = Transformer.get_persisted(dsl_state, :module)
+    api = Transformer.get_option(dsl_state, [:smokestack], :api)
+
+    dsl_state =
+      dsl_state
+      |> Transformer.get_entities([:smokestack])
+      |> Enum.reduce(dsl_state, fn
+        entity, dsl_state when is_struct(entity, Factory) ->
+          entity =
+            entity
+            |> Map.put(:module, module)
+            |> Map.update(:api, api, fn
+              nil -> api
+              api -> api
+            end)
+
+          Transformer.replace_entity(dsl_state, [:smokestack], entity)
+
+        _, dsl_state ->
+          dsl_state
+      end)
+
     {:ok, dsl_state}
   end
 end
diff --git a/lib/smokestack/param_builder.ex b/lib/smokestack/param_builder.ex
new file mode 100644
index 0000000..d419bba
--- /dev/null
+++ b/lib/smokestack/param_builder.ex
@@ -0,0 +1,201 @@
+defmodule Smokestack.ParamBuilder do
+  @moduledoc """
+  Handles the building of parameters.
+  """
+
+  alias Ash.Resource
+  alias Smokestack.{Dsl.Attribute, Dsl.Factory, Dsl.Info, Template}
+
+  @param_option_defaults %{keys: :atom, as: :map, build: [], attrs: %{}, variant: :default}
+
+  @typedoc "Options that can be passed to `params/4`."
+  @type param_options :: [param_keys_option | param_as_option | build_option | param_variant]
+
+  @typedoc "Key type in the result. Defaults to `#{inspect(@param_option_defaults[:keys])}`."
+  @type param_keys_option :: {:keys, :atom | :string | :dasherise}
+
+  @typedoc "Result type. Defaults to `#{inspect(@param_option_defaults[:as])}`"
+  @type param_as_option :: {:as, :map | :list}
+
+  @typedoc "Choose a specific factory variant. Defaults to `:default`."
+  @type param_variant :: {:variant, atom}
+
+  @typedoc "Specify attribute overrides."
+  @type param_attrs :: {:attrs, Enumerable.t({atom, any})}
+
+  @type param_result ::
+          %{required(atom | String.t()) => any}
+          | [{atom | String.t(), any}]
+
+  @typedoc "A nested keyword list of associations that should also be built"
+  @type build_option :: {:build, Smokestack.recursive_atom_list()}
+
+  @doc """
+  Build parameters for a resource with a factory.
+  """
+  @spec build(Smokestack.t(), Resource.t(), param_options) :: {:ok, param_result} | {:error, any}
+  def build(factory_module, resource, options \\ [])
+      when is_atom(factory_module) and is_atom(resource) and is_list(options) do
+    with {:ok, options} <- validate_options(options),
+         {:ok, factory} <- Info.factory(factory_module, resource, options[:variant]) do
+      build_factory(factory, options)
+    end
+  end
+
+  @doc "Raising version of `build/2..5`."
+  @spec build!(Smokestack.t(), Resource.t(), param_options) :: param_result | no_return
+  def build!(factory_module, resource, options \\ []) do
+    case build(factory_module, resource, options) do
+      {:ok, params} -> params
+      {:error, reason} -> raise reason
+    end
+  end
+
+  @doc false
+  @spec build_factory(Factory.t(), param_options) :: {:ok, param_result()} | {:error, any}
+  def build_factory(factory, options \\ []) do
+    with {:ok, params} <- build_params(factory, options) do
+      params =
+        params
+        |> maybe_stringify_keys(options)
+        |> maybe_dasherise_keys(options)
+        |> maybe_listify_result(options)
+
+      {:ok, params}
+    end
+  end
+
+  @doc false
+  @spec validate_options(Enumerable.t({atom, any})) :: {:ok, param_options()}
+  def validate_options(options) do
+    opt_map = Map.new(options)
+
+    Enum.reduce(@param_option_defaults, {:ok, []}, fn
+      {key, _}, {:ok, options} when is_map_key(opt_map, key) ->
+        {:ok, [{key, Map.get(opt_map, key)} | options]}
+
+      {key, value}, {:ok, options} ->
+        {:ok, [{key, value} | options]}
+    end)
+  end
+
+  defp build_params(factory, options) do
+    overrides = Map.new(options[:attrs])
+
+    factory
+    |> Map.get(:attributes, [])
+    |> Enum.filter(&is_struct(&1, Attribute))
+    |> Enum.reduce(%{}, fn
+      attr, attrs when is_map_key(overrides, attr.name) ->
+        Map.put(attrs, attr.name, Map.get(overrides, attr.name))
+
+      attr, attrs ->
+        generator = maybe_initialise_generator(attr)
+        value = Template.generate(generator, attrs, options)
+        Map.put(attrs, attr.name, value)
+    end)
+    |> maybe_build_related(factory, options)
+  end
+
+  defp maybe_build_related(params, factory, options) do
+    options
+    |> Keyword.get(:build, [])
+    |> List.wrap()
+    |> Enum.map(fn
+      {key, value} -> {key, value}
+      key when is_atom(key) -> {key, []}
+    end)
+    |> Enum.reduce_while({:ok, params}, fn {relationship, nested_builds}, {:ok, params} ->
+      case build_related(
+             params,
+             relationship,
+             factory,
+             Keyword.put(options, :build, nested_builds)
+           ) do
+        {:ok, params} -> {:cont, {:ok, params}}
+        {:error, reason} -> {:halt, {:error, reason}}
+      end
+    end)
+  end
+
+  defp build_related(params, relationship, factory, options) do
+    ash_relationship = Resource.Info.relationship(factory.resource, relationship)
+    build_related(params, relationship, factory, options, ash_relationship)
+  end
+
+  defp build_related(_params, relationship, factory, _options, nil),
+    do:
+      {:error,
+       "Relationship `#{inspect(relationship)}` not defined in resource `#{inspect(factory.resource)}`."}
+
+  defp build_related(params, _, factory, options, relationship)
+       when relationship.cardinality == :one do
+    with {:ok, related_factory} <-
+           find_related_factory(relationship.destination, factory),
+         {:ok, related_params} <- build_params(related_factory, Keyword.put(options, :attrs, %{})) do
+      {:ok, Map.put(params, relationship.name, related_params)}
+    end
+  end
+
+  defp build_related(params, _, factory, options, relationship)
+       when relationship.cardinality == :many do
+    with {:ok, related_factory} <-
+           find_related_factory(relationship.destination, factory),
+         {:ok, related_params} <- build_params(related_factory, Keyword.put(options, :attrs, %{})) do
+      {:ok, Map.put(params, relationship.name, [related_params])}
+    end
+  end
+
+  defp find_related_factory(resource, factory) when factory.variant == :default,
+    do: Info.factory(factory.module, resource, :default)
+
+  defp find_related_factory(resource, factory) do
+    with {:error, _} <- Info.factory(factory.module, resource, factory.variant),
+         {:error, _} <- Info.factory(factory.module, resource, :default) do
+      {:error,
+       ArgumentError.exception(
+         message:
+           "Factory for `#{inspect(resource)}` no variant named `#{inspect(factory.variant)}` or `:default` found."
+       )}
+    end
+  end
+
+  defp maybe_initialise_generator(attr) do
+    with nil <- Process.get(attr.__identifier__),
+         generator <- Template.init(attr.generator) do
+      Process.put(attr.__identifier__, generator)
+      generator
+    end
+  end
+
+  defp maybe_stringify_keys(attrs, options) do
+    if Keyword.get(options, :keys, @param_option_defaults[:keys]) == :string do
+      Map.new(attrs, fn {key, value} -> {Atom.to_string(key), value} end)
+    else
+      attrs
+    end
+  end
+
+  defp maybe_dasherise_keys(attrs, options) do
+    if Keyword.get(options, :keys, @param_option_defaults[:keys]) == :dasherise do
+      Map.new(attrs, fn {key, value} ->
+        key =
+          key
+          |> Atom.to_string()
+          |> String.replace("_", "-")
+
+        {key, value}
+      end)
+    else
+      attrs
+    end
+  end
+
+  defp maybe_listify_result(attrs, options) do
+    if Keyword.get(options, :as, @param_option_defaults[:as]) == :list do
+      Enum.to_list(attrs)
+    else
+      attrs
+    end
+  end
+end
diff --git a/lib/smokestack/record_builder.ex b/lib/smokestack/record_builder.ex
new file mode 100644
index 0000000..b049059
--- /dev/null
+++ b/lib/smokestack/record_builder.ex
@@ -0,0 +1,89 @@
+defmodule Smokestack.RecordBuilder do
+  @moduledoc """
+  Handles the insertion of new records.
+  """
+
+  alias Ash.{Resource, Seed}
+  alias Smokestack.{Dsl.Info, ParamBuilder}
+
+  @insert_option_defaults %{load: [], attrs: %{}, variant: :default}
+
+  @type insert_options :: ParamBuilder.param_options() | [load_option()]
+
+  @typedoc "A nested keyword list of associations, calculations and aggregates to load"
+  @type load_option :: {:load, Smokestack.recursive_atom_list()}
+
+  @type insert_result :: Resource.record()
+
+  @doc """
+  Insert a resource record with a factory.
+  """
+  @spec build(Smokestack.t(), Resource.t(), insert_options) ::
+          {:ok, insert_result()} | {:error, any}
+  def build(factory_module, resource, options \\ [])
+      when is_atom(factory_module) and is_atom(resource) and is_list(options) do
+    with {:ok, insert_opts, param_opts} <- split_options(options),
+         {:ok, factory} <- Info.factory(factory_module, resource, insert_opts[:variant]),
+         {:ok, params} <- ParamBuilder.build_factory(factory, param_opts),
+         {:ok, record} <- do_seed(resource, params, factory_module, insert_opts[:variant]) do
+      maybe_load(factory, record, insert_opts)
+    end
+  end
+
+  @doc "Raising version of `build/3`"
+  @spec build!(Smokestack.t(), Resource.t(), insert_options) ::
+          insert_result() | no_return
+  def build!(factory_module, resource, options \\ []) do
+    case build(factory_module, resource, options) do
+      {:ok, params} -> params
+      {:error, reason} -> raise reason
+    end
+  end
+
+  defp maybe_load(factory, record, options) do
+    options
+    |> Keyword.get(:load, [])
+    |> List.wrap()
+    |> case do
+      [] ->
+        {:ok, record}
+
+      _loads when is_nil(factory.api) ->
+        {:error, "Unable to perform `load` operation without an API."}
+
+      loads ->
+        factory.api.load(record, loads, [])
+    end
+  end
+
+  defp do_seed(resource, params, factory_module, variant) do
+    record =
+      resource
+      |> Seed.seed!(params)
+      |> Resource.put_metadata(:factory, factory_module)
+      |> Resource.put_metadata(:variant, variant)
+
+    {:ok, record}
+  rescue
+    error -> {:error, error}
+  end
+
+  defp split_options(options) do
+    with {:ok, param_options} <- ParamBuilder.validate_options(options),
+         {:ok, insert_options} <- validate_options(options) do
+      {:ok, insert_options, param_options}
+    end
+  end
+
+  defp validate_options(options) do
+    opt_map = Map.new(options)
+
+    Enum.reduce(@insert_option_defaults, {:ok, []}, fn
+      {key, _}, {:ok, options} when is_map_key(opt_map, key) ->
+        {:ok, [{key, Map.get(opt_map, key)} | options]}
+
+      {key, value}, {:ok, options} ->
+        {:ok, [{key, value} | options]}
+    end)
+  end
+end
diff --git a/test/smokestack/builder_test.exs b/test/smokestack/builder_test.exs
deleted file mode 100644
index affacf4..0000000
--- a/test/smokestack/builder_test.exs
+++ /dev/null
@@ -1,54 +0,0 @@
-defmodule Smokestack.BuilderTest do
-  @moduledoc false
-  use ExUnit.Case, async: true
-
-  alias Smokestack.Builder
-  alias Support.{Factory, Post}
-
-  describe "params/2..5" do
-    test "it builds params" do
-      assert {:ok, params} = Builder.params(Factory, Post)
-      assert params |> Map.keys() |> Enum.sort() == ~w[body sub_title tags title]a
-      assert is_binary(params.body)
-      assert Enum.all?(params.tags, &is_binary/1)
-      assert is_binary(params.title)
-    end
-
-    test "it honours the `as: :list` option" do
-      assert {:ok, params} = Builder.params(Factory, Post, %{}, :default, as: :list)
-      assert is_list(params)
-      assert is_binary(params[:body])
-      assert Enum.all?(params[:tags], &is_binary/1)
-      assert is_binary(params[:title])
-    end
-
-    test "it honours the `keys: :string` option" do
-      assert {:ok, params} = Builder.params(Factory, Post, %{}, :default, keys: :string)
-      assert is_binary(params["body"])
-      assert Enum.all?(params["tags"], &is_binary/1)
-      assert is_binary(params["title"])
-    end
-
-    test "it honours the `keys: :dasherise` option" do
-      assert {:ok, params} = Builder.params(Factory, Post, %{}, :default, keys: :dasherise)
-      assert is_binary(params["sub-title"])
-    end
-  end
-
-  describe "insert/2..5" do
-    test "it inserts the resource" do
-      assert {:ok, record} = Builder.insert(Factory, Post)
-      assert is_struct(record, Post)
-      assert record.inserted_at
-      assert is_binary(record.title)
-      assert is_binary(record.sub_title)
-      assert Enum.all?(record.tags, &is_struct(&1, Ash.CiString))
-    end
-  end
-
-  describe "insert_many/3..5" do
-    assert {:ok, records} = Builder.insert_many(Factory, Post, 3)
-    assert length(records) == 3
-    assert Enum.all?(records, &is_struct(&1, Post))
-  end
-end
diff --git a/test/smokestack/param_builder_test.exs b/test/smokestack/param_builder_test.exs
new file mode 100644
index 0000000..4f2d708
--- /dev/null
+++ b/test/smokestack/param_builder_test.exs
@@ -0,0 +1,58 @@
+defmodule Smokestack.ParamBuilderTest do
+  @moduledoc false
+  use ExUnit.Case, async: true
+
+  alias Smokestack.ParamBuilder
+  alias Support.{Author, Factory, Post}
+
+  describe "build/2..5" do
+    test "it builds params" do
+      assert {:ok, params} = ParamBuilder.build(Factory, Post)
+      assert params |> Map.keys() |> Enum.sort() == ~w[body sub_title tags title]a
+      assert params.body
+      assert Enum.all?(params.tags, &is_binary/1)
+      assert params.title
+    end
+
+    test "it honours the `as: :list` option" do
+      assert {:ok, params} = ParamBuilder.build(Factory, Post, as: :list)
+      assert is_list(params)
+      assert params[:body]
+      assert Enum.all?(params[:tags], &is_binary/1)
+      assert params[:title]
+    end
+
+    test "it honours the `keys: :string` option" do
+      assert {:ok, params} = ParamBuilder.build(Factory, Post, keys: :string)
+      assert params["body"]
+      assert Enum.all?(params["tags"], &is_binary/1)
+      assert params["title"]
+    end
+
+    test "it honours the `keys: :dasherise` option" do
+      assert {:ok, params} = ParamBuilder.build(Factory, Post, keys: :dasherise)
+      assert params["sub-title"]
+    end
+
+    test "it honours the `build` option for single relationships" do
+      assert {:ok, params} = ParamBuilder.build(Factory, Post, build: :author)
+      assert params.author.name
+      assert params.author.email
+    end
+
+    test "it honours the `build` option for many relationships" do
+      assert {:ok, params} = ParamBuilder.build(Factory, Author, build: :posts)
+      assert [post] = params.posts
+      assert post.title
+    end
+
+    test "it honours nested `build` options" do
+      assert {:ok, params} =
+               ParamBuilder.build(Factory, Author, build: [posts: [:author]])
+
+      assert [post] = params.posts
+      assert post.author.name
+      assert params.name != post.author.name
+    end
+  end
+end
diff --git a/test/smokestack/record_builder_test.exs b/test/smokestack/record_builder_test.exs
new file mode 100644
index 0000000..872066b
--- /dev/null
+++ b/test/smokestack/record_builder_test.exs
@@ -0,0 +1,33 @@
+defmodule Smokestack.RecordBuilderTest do
+  @moduledoc false
+  use ExUnit.Case, async: true
+  alias Smokestack.RecordBuilder
+
+  describe "record/2..5" do
+    test "it can insert a record" do
+      assert {:ok, record} = RecordBuilder.build(Support.Factory, Support.Post)
+
+      assert record.__struct__ == Support.Post
+      assert record.__meta__.state == :loaded
+      refute record.author.__struct__ == Support.Author
+    end
+
+    test "it can insert related records" do
+      assert {:ok, record} =
+               RecordBuilder.build(Support.Factory, Support.Post, build: [:author])
+
+      assert record.__struct__ == Support.Post
+      assert record.__meta__.state == :loaded
+      assert record.author.__struct__ == Support.Author
+      assert record.author.__meta__.state == :loaded
+    end
+
+    test "it can perform a load on a record" do
+      assert {:ok, record} =
+               RecordBuilder.build(Support.Factory, Support.Post, load: :full_title)
+
+      assert record.__struct__ == Support.Post
+      assert record.full_title =~ ":"
+    end
+  end
+end
diff --git a/test/support/factory.ex b/test/support/factory.ex
index 64e32d9..a5d4ed8 100644
--- a/test/support/factory.ex
+++ b/test/support/factory.ex
@@ -20,6 +20,8 @@ defmodule Support.Factory do
   end
 
   factory Support.Post do
+    api Support.Api
+
     attribute :title, &Faker.Commerce.product_name/0
     attribute :tags, n_times(3..20, &Faker.Lorem.word/0)
     attribute :body, &Faker.Markdown.markdown/0
diff --git a/test/support/post.ex b/test/support/post.ex
index 3cb4c95..8afce4a 100644
--- a/test/support/post.ex
+++ b/test/support/post.ex
@@ -39,4 +39,8 @@ defmodule Support.Post do
   actions do
     defaults [:create, :read, :update, :destroy]
   end
+
+  calculations do
+    calculate :full_title, :string, concat([:title, :sub_title], ": ")
+  end
 end