diff --git a/.formatter.exs b/.formatter.exs
index b32773d..3754057 100644
--- a/.formatter.exs
+++ b/.formatter.exs
@@ -1,6 +1,10 @@
 spark_locals_without_parens = [
+  after_build: 1,
+  after_build: 2,
   attribute: 2,
   attribute: 3,
+  before_build: 1,
+  before_build: 2,
   domain: 1,
   factory: 1,
   factory: 2,
diff --git a/documentation/dsls/DSL:-Smokestack.md b/documentation/dsls/DSL:-Smokestack.md
index fa2c3ec..2cc4c64 100644
--- a/documentation/dsls/DSL:-Smokestack.md
+++ b/documentation/dsls/DSL:-Smokestack.md
@@ -13,7 +13,9 @@ The DSL definition for the Smokestack DSL.
 
   * smokestack
     * factory
+      * after_build
       * attribute
+      * before_build
 
 ### Docs
 
@@ -22,7 +24,9 @@ The DSL definition for the Smokestack DSL.
 
 
  * [factory](#module-factory)
+   * after_build
    * attribute
+   * before_build
 
 
 
@@ -38,7 +42,9 @@ The DSL definition for the Smokestack DSL.
 
 Define factories for a resource
 
+    * after_build
     * attribute
+    * before_build
 
 
 
@@ -50,6 +56,26 @@ Define factories for a resource
 
 
 
+##### after_build
+
+Modify the record after building.
+
+Allows you to provide a function which can modify the built record before returning.
+
+These hooks are only applied when building records and not parameters.
+
+
+
+
+
+
+* `:hook` (mfa or function of arity 1) - Required. A function which returns an updated record
+
+
+
+
+
+
 ##### attribute
 
 
@@ -67,6 +93,24 @@ Define factories for a resource
 
 
 
+##### before_build
+
+Modify the attributes before building.
+
+Allows you to provide a function which can modify the the attributes before building.
+
+
+
+
+
+
+* `:hook` (mfa or function of arity 1) - Required. A function which returns an updated record
+
+
+
+
+
+
 
 
 
@@ -79,7 +123,9 @@ Define factories for a resource
 
 ### Nested DSLs
  * [factory](#smokestack-factory)
+   * after_build
    * attribute
+   * before_build
 
 
 
@@ -102,7 +148,9 @@ factory resource, variant \\ :default
 Define factories for a resource
 
 ### Nested DSLs
+ * [after_build](#smokestack-factory-after_build)
  * [attribute](#smokestack-factory-attribute)
+ * [before_build](#smokestack-factory-before_build)
 
 
 
@@ -120,6 +168,38 @@ Define factories for a resource
 | [`domain`](#smokestack-factory-domain){: #smokestack-factory-domain } | `module` |  | The Ash Domain to use when evaluating loads |
 
 
+## smokestack.factory.after_build
+```elixir
+after_build hook
+```
+
+
+Modify the record after building.
+
+Allows you to provide a function which can modify the built record before returning.
+
+These hooks are only applied when building records and not parameters.
+
+
+
+
+
+
+### Arguments
+
+| Name | Type | Default | Docs |
+|------|------|---------|------|
+| [`hook`](#smokestack-factory-after_build-hook){: #smokestack-factory-after_build-hook .spark-required} | `(any -> any) \| mfa` |  | A function which returns an updated record |
+
+
+
+
+
+
+### Introspection
+
+Target: `Smokestack.Dsl.AfterBuild`
+
 ## smokestack.factory.attribute
 ```elixir
 attribute name, generator
@@ -148,6 +228,36 @@ attribute name, generator
 
 Target: `Smokestack.Dsl.Attribute`
 
+## smokestack.factory.before_build
+```elixir
+before_build hook
+```
+
+
+Modify the attributes before building.
+
+Allows you to provide a function which can modify the the attributes before building.
+
+
+
+
+
+
+### Arguments
+
+| Name | Type | Default | Docs |
+|------|------|---------|------|
+| [`hook`](#smokestack-factory-before_build-hook){: #smokestack-factory-before_build-hook .spark-required} | `(any -> any) \| mfa` |  | A function which returns an updated record |
+
+
+
+
+
+
+### Introspection
+
+Target: `Smokestack.Dsl.BeforeBuild`
+
 
 
 
diff --git a/lib/smokestack/builders/factory_builder.ex b/lib/smokestack/builders/factory_builder.ex
index 83098a7..43301ee 100644
--- a/lib/smokestack/builders/factory_builder.ex
+++ b/lib/smokestack/builders/factory_builder.ex
@@ -27,13 +27,22 @@ defmodule Smokestack.FactoryBuilder do
     overrides = Keyword.get(options, :attrs, %{})
 
     with {:ok, overrides} <- validate_overrides(factory, overrides) do
-      factory.attributes
-      |> remove_overridden_attrs(overrides)
-      |> Enum.reduce({:ok, overrides}, fn attr, {:ok, attrs} ->
-        generator = maybe_initialise_generator(attr)
-        value = Template.generate(generator, attr, options)
-        {:ok, Map.put(attrs, attr.name, value)}
-      end)
+      attrs =
+        factory.attributes
+        |> remove_overridden_attrs(overrides)
+        |> Enum.reduce(overrides, fn attr, attrs ->
+          generator = maybe_initialise_generator(attr)
+          value = Template.generate(generator, attr, options)
+          Map.put(attrs, attr.name, value)
+        end)
+
+      attrs =
+        factory.before_build
+        |> Enum.reduce(attrs, fn hook, attrs ->
+          hook.hook.(attrs)
+        end)
+
+      {:ok, attrs}
     end
   end
 
diff --git a/lib/smokestack/builders/record_builder.ex b/lib/smokestack/builders/record_builder.ex
index fc60913..8e02dec 100644
--- a/lib/smokestack/builders/record_builder.ex
+++ b/lib/smokestack/builders/record_builder.ex
@@ -100,7 +100,9 @@ defmodule Smokestack.RecordBuilder do
 
     with {:ok, attr_list} <- Builder.build(ManyBuilder, factory, options),
          {:ok, record_list} <- seed(attr_list, factory) do
-      maybe_load(record_list, factory, load)
+      record_list
+      |> maybe_hook(factory)
+      |> maybe_load(factory, load)
     end
   end
 
@@ -109,7 +111,9 @@ defmodule Smokestack.RecordBuilder do
 
     with {:ok, attrs} <- Builder.build(RelatedBuilder, factory, options),
          {:ok, record} <- seed(attrs, factory) do
-      maybe_load(record, factory, load)
+      record
+      |> maybe_hook(factory)
+      |> maybe_load(factory, load)
     end
   end
 
@@ -148,4 +152,18 @@ defmodule Smokestack.RecordBuilder do
 
   defp maybe_load(record_or_records, factory, load),
     do: Ash.load(record_or_records, load, domain: factory.domain)
+
+  defp maybe_hook(records, factory) when is_list(records) do
+    Enum.map(records, fn record ->
+      Enum.reduce(factory.after_build, record, fn hook, record ->
+        hook.(record)
+      end)
+    end)
+  end
+
+  defp maybe_hook(record, factory) when is_map(record) do
+    Enum.reduce(factory.after_build, record, fn hook, record ->
+      hook.hook.(record)
+    end)
+  end
 end
diff --git a/lib/smokestack/dsl/after_build.ex b/lib/smokestack/dsl/after_build.ex
new file mode 100644
index 0000000..f6d6ba0
--- /dev/null
+++ b/lib/smokestack/dsl/after_build.ex
@@ -0,0 +1,43 @@
+defmodule Smokestack.Dsl.AfterBuild do
+  @moduledoc """
+  The `after_build` DSL entity.
+
+  See `d:Smokestack.factory.after_build` for more information.
+  """
+
+  defstruct __identifier__: nil, hook: nil
+
+  alias Ash.Resource
+  alias Spark.Dsl.Entity
+
+  @type t :: %__MODULE__{
+          __identifier__: any,
+          hook: mfa | (Resource.record() -> Resource.record())
+        }
+
+  @doc false
+  @spec __entities__ :: [Entity.t()]
+  def __entities__,
+    do: [
+      %Entity{
+        name: :after_build,
+        describe: """
+        Modify the record after building.
+
+        Allows you to provide a function which can modify the built record before returning.
+
+        These hooks are only applied when building records and not parameters.
+        """,
+        target: __MODULE__,
+        args: [:hook],
+        identifier: {:auto, :unique_integer},
+        schema: [
+          hook: [
+            type: {:mfa_or_fun, 1},
+            required: true,
+            doc: "A function which returns an updated record"
+          ]
+        ]
+      }
+    ]
+end
diff --git a/lib/smokestack/dsl/attribute.ex b/lib/smokestack/dsl/attribute.ex
index 305854b..7b05363 100644
--- a/lib/smokestack/dsl/attribute.ex
+++ b/lib/smokestack/dsl/attribute.ex
@@ -2,7 +2,7 @@ defmodule Smokestack.Dsl.Attribute do
   @moduledoc """
   The `attribute ` DSL entity.
 
-  See `d:Smokestack.factory.default.attribute` for more information.
+  See `d:Smokestack.factory.attribute` for more information.
   """
 
   defstruct __identifier__: nil, generator: nil, name: nil
@@ -11,7 +11,7 @@ defmodule Smokestack.Dsl.Attribute do
   alias Spark.Dsl.Entity
 
   @type t :: %__MODULE__{
-          __identifier__: nil,
+          __identifier__: any,
           generator:
             mfa | (-> any) | (Resource.record() -> any) | (Resource.record(), keyword -> any),
           name: atom
diff --git a/lib/smokestack/dsl/before_build.ex b/lib/smokestack/dsl/before_build.ex
new file mode 100644
index 0000000..8428230
--- /dev/null
+++ b/lib/smokestack/dsl/before_build.ex
@@ -0,0 +1,41 @@
+defmodule Smokestack.Dsl.BeforeBuild do
+  @moduledoc """
+  The `before_build` DSL entity.
+
+  See `d:Smokestack.factory.before_build` for more information.
+  """
+
+  defstruct __identifier__: nil, hook: nil
+
+  alias Spark.Dsl.Entity
+
+  @type attrs :: %{required(String.t() | atom) => any}
+  @type t :: %__MODULE__{
+          __identifier__: any,
+          hook: mfa | (attrs -> attrs)
+        }
+
+  @doc false
+  @spec __entities__ :: [Entity.t()]
+  def __entities__,
+    do: [
+      %Entity{
+        name: :before_build,
+        describe: """
+        Modify the attributes before building.
+
+        Allows you to provide a function which can modify the the attributes before building.
+        """,
+        target: __MODULE__,
+        args: [:hook],
+        identifier: {:auto, :unique_integer},
+        schema: [
+          hook: [
+            type: {:mfa_or_fun, 1},
+            required: true,
+            doc: "A function which returns an updated record"
+          ]
+        ]
+      }
+    ]
+end
diff --git a/lib/smokestack/dsl/factory.ex b/lib/smokestack/dsl/factory.ex
index 16e31d4..d4b1081 100644
--- a/lib/smokestack/dsl/factory.ex
+++ b/lib/smokestack/dsl/factory.ex
@@ -6,19 +6,23 @@ defmodule Smokestack.Dsl.Factory do
   """
 
   defstruct __identifier__: nil,
+            after_build: [],
             attributes: [],
+            before_build: [],
             domain: nil,
             module: nil,
             resource: nil,
             variant: :default
 
   alias Ash.Resource
-  alias Smokestack.Dsl.{Attribute, Template}
+  alias Smokestack.Dsl.{AfterBuild, Attribute, BeforeBuild, Template}
   alias Spark.Dsl.Entity
 
   @type t :: %__MODULE__{
           __identifier__: any,
+          after_build: [AfterBuild.t()],
           attributes: [Attribute.t()],
+          before_build: [BeforeBuild.t()],
           domain: nil,
           module: module,
           resource: Resource.t(),
@@ -54,7 +58,11 @@ defmodule Smokestack.Dsl.Factory do
             default: :default
           ]
         ],
-        entities: [attributes: Attribute.__entities__()]
+        entities: [
+          after_build: AfterBuild.__entities__(),
+          attributes: Attribute.__entities__(),
+          before_build: BeforeBuild.__entities__()
+        ]
       }
     ]
 end
diff --git a/mix.lock b/mix.lock
index 079d709..94fb018 100644
--- a/mix.lock
+++ b/mix.lock
@@ -19,14 +19,14 @@
   "git_ops": {:hex, :git_ops, "2.6.1", "cc7799a68c26cf814d6d1a5121415b4f5bf813de200908f930b27a2f1fe9dad5", [:mix], [{:git_cli, "~> 0.2", [hex: :git_cli, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "ce62d07e41fe993ec22c35d5edb11cf333a21ddaead6f5d9868fcb607d42039e"},
   "jason": {:hex, :jason, "1.4.1", "af1504e35f629ddcdd6addb3513c3853991f694921b1b9368b0bd32beb9f1b63", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "fbb01ecdfd565b56261302f7e1fcc27c4fb8f32d56eab74db621fc154604a7a1"},
   "libgraph": {:hex, :libgraph, "0.16.0", "3936f3eca6ef826e08880230f806bfea13193e49bf153f93edcf0239d4fd1d07", [:mix], [], "hexpm", "41ca92240e8a4138c30a7e06466acc709b0cbb795c643e9e17174a178982d6bf"},
-  "makeup": {:hex, :makeup, "1.1.2", "9ba8837913bdf757787e71c1581c21f9d2455f4dd04cfca785c70bbfff1a76a3", [], [{:nimble_parsec, "~> 1.2.2 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "cce1566b81fbcbd21eca8ffe808f33b221f9eee2cbc7a1706fc3da9ff18e6cac"},
+  "makeup": {:hex, :makeup, "1.1.2", "9ba8837913bdf757787e71c1581c21f9d2455f4dd04cfca785c70bbfff1a76a3", [:mix], [{:nimble_parsec, "~> 1.2.2 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "cce1566b81fbcbd21eca8ffe808f33b221f9eee2cbc7a1706fc3da9ff18e6cac"},
   "makeup_elixir": {:hex, :makeup_elixir, "0.16.2", "627e84b8e8bf22e60a2579dad15067c755531fea049ae26ef1020cad58fe9578", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.2.3 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "41193978704763f6bbe6cc2758b84909e62984c7752b3784bd3c218bb341706b"},
   "makeup_erlang": {:hex, :makeup_erlang, "1.0.0", "6f0eff9c9c489f26b69b61440bf1b238d95badae49adac77973cbacae87e3c2e", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "ea7a9307de9d1548d2a72d299058d1fd2339e3d398560a0e46c27dab4891e4d2"},
   "mix_audit": {:hex, :mix_audit, "2.1.3", "c70983d5cab5dca923f9a6efe559abfb4ec3f8e87762f02bab00fa4106d17eda", [:make, :mix], [{:jason, "~> 1.1", [hex: :jason, repo: "hexpm", optional: false]}, {:yaml_elixir, "~> 2.9", [hex: :yaml_elixir, repo: "hexpm", optional: false]}], "hexpm", "8c3987100b23099aea2f2df0af4d296701efd031affb08d0746b2be9e35988ec"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.0", "51f9b613ea62cfa97b25ccc2c1b4216e81df970acd8e16e8d1bdc58fef21370d", [:mix], [], "hexpm", "9c565862810fb383e9838c1dd2d7d2c437b3d13b267414ba6af33e50d2d1cf28"},
   "reactor": {:hex, :reactor, "0.8.2", "b2be82b1c3402537d06a8f85bb1849f72cb6b4be140495cb8956de7aec2fdebd", [:mix], [{:libgraph, "~> 0.16", [hex: :libgraph, repo: "hexpm", optional: false]}, {:spark, "~> 2.0", [hex: :spark, repo: "hexpm", optional: false]}, {:splode, "~> 0.2", [hex: :splode, repo: "hexpm", optional: false]}, {:telemetry, "~> 1.2", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "c35eb23b77cc77ba922af108722ac93257899e35cfdd18882f0e659ad2cac9f3"},
   "recase": {:hex, :recase, "0.7.0", "3f2f719f0886c7a3b7fe469058ec539cb7bbe0023604ae3bce920e186305e5ae", [:mix], [], "hexpm", "36f5756a9f552f4a94b54a695870e32f4e72d5fad9c25e61bc4a3151c08a4e0c"},
-  "sourceror": {:hex, :sourceror, "1.2.1", "b415255ad8bd05f0e859bb3d7ea617f6c2a4a405f2a534a231f229bd99b89f8b", [], [], "hexpm", "e4d97087e67584a7585b5fe3d5a71bf8e7332f795dd1a44983d750003d5e750c"},
+  "sourceror": {:hex, :sourceror, "1.2.1", "b415255ad8bd05f0e859bb3d7ea617f6c2a4a405f2a534a231f229bd99b89f8b", [:mix], [], "hexpm", "e4d97087e67584a7585b5fe3d5a71bf8e7332f795dd1a44983d750003d5e750c"},
   "spark": {:hex, :spark, "2.1.22", "a36400eede64c51af578de5fdb5a5aaa3e0811da44bcbe7545fce059bd2a990b", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:sourceror, "~> 1.0", [hex: :sourceror, repo: "hexpm", optional: false]}], "hexpm", "f764611d0b15ac132e72b2326539acc11fc4e63baa3e429f541bca292b5f7064"},
   "splode": {:hex, :splode, "0.2.4", "71046334c39605095ca4bed5d008372e56454060997da14f9868534c17b84b53", [:mix], [], "hexpm", "ca3b95f0d8d4b482b5357954fec857abd0fa3ea509d623334c1328e7382044c2"},
   "stream_data": {:hex, :stream_data, "1.0.0", "c1380747a4650902732696861d5cb66ad3cb1cc93f31c2c8498bf87cddbabe2d", [:mix], [], "hexpm", "acd53e27c66c617d466f42ec77a7f59e5751f6051583c621ccdb055b9690435d"},
diff --git a/test/smokestack/dsl_test.exs b/test/smokestack/dsl_test.exs
index 6c95d78..3d23c78 100644
--- a/test/smokestack/dsl_test.exs
+++ b/test/smokestack/dsl_test.exs
@@ -107,4 +107,42 @@ defmodule Smokestack.DslTest do
     assert %Post{title: title} = FactoryUser.test()
     assert title =~ ~r/[a-z]+/i
   end
+
+  test "before build hooks can be applied" do
+    defmodule BeforeBuildFactory do
+      @moduledoc false
+      use Smokestack
+
+      factory Post do
+        attribute :title, &Faker.Company.catch_phrase/0
+        before_build &capitalise_title/1
+      end
+
+      def capitalise_title(record) do
+        %{record | title: String.upcase(record.title)}
+      end
+    end
+
+    title = Faker.Company.catch_phrase()
+    upper_title = String.upcase(title)
+    assert %Post{title: ^upper_title} = BeforeBuildFactory.insert!(Post, attrs: %{title: title})
+  end
+
+  test "after build hooks can be applied" do
+    defmodule AfterBuildFactory do
+      @moduledoc false
+      use Smokestack
+
+      factory Post do
+        attribute :title, &Faker.Company.catch_phrase/0
+        after_build &add_metadata/1
+      end
+
+      def add_metadata(record) do
+        Ash.Resource.put_metadata(record, :wat, true)
+      end
+    end
+
+    assert %Post{__metadata__: %{wat: true}} = AfterBuildFactory.insert!(Post)
+  end
 end