diff --git a/.gitignore b/.gitignore
index 5bbdeed..e0eae69 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,3 +22,4 @@ erl_crash.dump
 # Ignore package tarball (built via "mix hex.build").
 mentat-*.tar
 
+.expert
diff --git a/lib/mentat.ex b/lib/mentat.ex
index 9f36e8d..17a776c 100644
--- a/lib/mentat.ex
+++ b/lib/mentat.ex
@@ -8,7 +8,55 @@ defmodule Mentat do
   use Supervisor
   use Oath
 
-  @type cache_opts() :: Keyword.t()
+  @cache_opts NimbleOptions.new!([
+    name: [
+      type: :atom,
+      doc: "The cache name as an atom",
+      required: true
+    ],
+    cleanup_interval: [
+      type: :pos_integer,
+      doc: "How often the janitor process will remove old keys.",
+      default: 5_000
+    ],
+    ets_args: [
+      type: {:list, :any},
+      doc: "Additional arguments to pass to `:ets.new/2`",
+      default: []
+    ],
+    ttl: [
+      type: :timeout,
+      doc: "The default ttl for all keys. Defaults to `:infinity`.",
+      default: :infinity
+    ],
+    limit: [
+      type: :keyword_list,
+      doc: "Limits to the number of keys a cache will store.",
+      keys: [
+        size: [
+          type: :pos_integer,
+          required: true,
+          doc: "The maximum number of values to store in the cache"
+        ],
+        reclaim: [
+          type: :float,
+          default: 0.1,
+          doc: "The percentage of keys to reclaim if the limit is exceeded."
+        ]
+      ]
+    ],
+    clock: [
+      type: :any,
+      doc: false,
+      type_doc: false,
+      default: System
+    ]
+  ])
+
+  @default_limit %{reclaim: 0.1}
+
+  @type cache_opt() :: unquote(NimbleOptions.option_typespec(@cache_opts))
+  @type cache_opts() :: [cache_opt()]
   @type name :: atom()
   @type key :: term()
   @type value :: term()
@@ -16,28 +64,8 @@ defmodule Mentat do
     {:ttl, pos_integer() | :infinity},
   ]
 
-  @default_limit %{reclaim: 0.1}
-
   alias Mentat.Janitor
 
-  defp cache_opts do
-    import Norm
-
-    coll_of(
-      one_of([
-        {:name, spec(is_atom)},
-        {:cleanup_interval, spec(is_integer and & &1 > 0)},
-        {:ets_args, spec(is_list)},
-        {:ttl, one_of([spec(is_integer and & &1 > 0), :infinity])},
-        {:clock, spec(is_atom)},
-        {:limit, coll_of(one_of([
-          {:size, spec(is_integer and & &1 > 0)},
-          {:reclaim, spec(is_float)},
-        ]))}
-      ])
-    )
-  end
-
   @doc false
   def child_spec(opts) do
     name = opts[:name] || raise ArgumentError, ":name is required"
@@ -53,17 +81,11 @@ defmodule Mentat do
   Starts a new cache.
 
   Options:
-  * `:name` - the cache name as an atom. required.
-  * `:cleanup_interval` - How often the janitor process will remove old keys. Defaults to 5_000.
-  * `:ets_args` - Additional arguments to pass to `:ets.new/2`.
-  * `:ttl` - The default ttl for all keys. Default `:infinity`.
-  * `:limit` - Limits to the number of keys a cache will store. Defaults to `:none`.
-    * `:size` - The maximum number of values to store in the cache.
-    * `:reclaim` - The percentage of keys to reclaim if the limit is exceeded. Defaults to 0.1.
+  #{NimbleOptions.docs(@cache_opts)}
   """
   @spec start_link(cache_opts()) :: Supervisor.on_start()
   def start_link(args) do
-    args = Norm.conform!(args, cache_opts())
+    args = NimbleOptions.validate!(args, @cache_opts)
     name = args[:name]
     Supervisor.start_link(__MODULE__, args, name: name)
   end
@@ -245,12 +267,12 @@ defmodule Mentat do
 
   def init(args) do
     name     = args[:name]
-    interval = args[:cleanup_interval] || 5_000
+    interval = args[:cleanup_interval]
     limit    = args[:limit] || :none
     limit    = if limit != :none, do: Map.merge(@default_limit, Map.new(limit)), else: limit
     ets_args = args[:ets_args] || []
     clock    = args[:clock] || System
-    ttl      = args[:ttl] || :infinity
+    ttl      = args[:ttl]
     ^name    = :ets.new(name, [:set, :named_table, :public] ++ ets_args)
 
     put_config(name, %{limit: limit, ttl: ttl, clock: clock})
diff --git a/mix.exs b/mix.exs
index 08660a6..b97b8f6 100644
--- a/mix.exs
+++ b/mix.exs
@@ -33,7 +33,7 @@ defmodule Mentat.MixProject do
   defp deps do
     [
       {:telemetry, "~> 0.4 or ~> 1.0"},
-      {:norm, "~> 0.12"},
+      {:nimble_options, "~> 1.1"},
       {:oath, "~> 0.1"},
 
       {:credo, "~> 1.5", only: [:dev, :test], runtime: false},
diff --git a/mix.lock b/mix.lock
index 3abab90..51ffc49 100644
--- a/mix.lock
+++ b/mix.lock
@@ -12,8 +12,8 @@
   "makeup": {:hex, :makeup, "1.1.1", "fa0bc768698053b2b3869fa8a62616501ff9d11a562f3ce39580d60860c3a55e", [:mix], [{:nimble_parsec, "~> 1.2.2 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "5dc62fbdd0de44de194898b6710692490be74baa02d9d108bc29f007783b0b48"},
   "makeup_elixir": {:hex, :makeup_elixir, "0.16.1", "cc9e3ca312f1cfeccc572b37a09980287e243648108384b97ff2b76e505c3555", [: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", "e127a341ad1b209bd80f7bd1620a15693a9908ed780c3b763bccf7d200c767c6"},
   "makeup_erlang": {:hex, :makeup_erlang, "0.1.4", "29563475afa9b8a2add1b7a9c8fb68d06ca7737648f28398e04461f008b69521", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "f4ed47ecda66de70dd817698a703f8816daa91272e7e45812469498614ae8b29"},
+  "nimble_options": {:hex, :nimble_options, "1.1.1", "e3a492d54d85fc3fd7c5baf411d9d2852922f66e69476317787a7b2bb000a61b", [:mix], [], "hexpm", "821b2470ca9442c4b6984882fe9bb0389371b8ddec4d45a9504f00a66f650b44"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.0", "51f9b613ea62cfa97b25ccc2c1b4216e81df970acd8e16e8d1bdc58fef21370d", [:mix], [], "hexpm", "9c565862810fb383e9838c1dd2d7d2c437b3d13b267414ba6af33e50d2d1cf28"},
-  "norm": {:hex, :norm, "0.13.0", "2c562113f3205e3f195ee288d3bd1ab903743e7e9f3282562c56c61c4d95dec4", [:mix], [{:stream_data, "~> 0.5", [hex: :stream_data, repo: "hexpm", optional: true]}], "hexpm", "447cc96dd2d0e19dcb37c84b5fc0d6842aad69386e846af048046f95561d46d7"},
   "oath": {:hex, :oath, "0.1.1", "9e96fc0bc94c8e2fe2deb84641f8b4533b7753575ac1829e1db4180f2b5656c4", [:mix], [{:decorator, "~> 1.3", [hex: :decorator, repo: "hexpm", optional: false]}], "hexpm", "d7e32cf0555905d422e5a90e8a7ce49c123710caa0fa2f7840bddbc1a0e93103"},
   "propcheck": {:hex, :propcheck, "1.4.1", "c12908dbe6f572032928548089b34ff9d40672d5d70f1562e3a9e9058d226cc9", [:mix], [{:libgraph, "~> 0.13", [hex: :libgraph, repo: "hexpm", optional: false]}, {:proper, "~> 1.4", [hex: :proper, repo: "hexpm", optional: false]}], "hexpm", "e1b088f574785c3c7e864da16f39082d5599b3aaf89086d3f9be6adb54464b19"},
   "proper": {:hex, :proper, "1.4.0", "89a44b8c39d28bb9b4be8e4d715d534905b325470f2e0ec5e004d12484a79434", [:rebar3], [], "hexpm", "18285842185bd33efbda97d134a5cb5a0884384db36119fee0e3cfa488568cbb"},