diff --git a/config/runtime.exs b/config/runtime.exs
index 4778318..7b19085 100644
--- a/config/runtime.exs
+++ b/config/runtime.exs
@@ -44,8 +44,6 @@ config :cannery, Cannery.Repo,
   pool_size: String.to_integer(System.get_env("POOL_SIZE", "10")),
   socket_options: maybe_ipv6
 
-config :cannery, Cannery.Accounts, registration: System.get_env("REGISTRATION", "invite")
-
 config :cannery, CanneryWeb.Endpoint,
   url: [scheme: "https", host: host, port: 443],
   http: [
@@ -56,6 +54,10 @@ config :cannery, CanneryWeb.Endpoint,
   ],
   server: true
 
+if config_env() in [:dev, :prod] do
+  config :cannery, Cannery.Accounts, registration: System.get_env("REGISTRATION", "invite")
+end
+
 if config_env() == :prod do
   # The secret key base is used to sign/encrypt cookies and other secrets.
   # A default value is used in config/dev.exs and config/test.exs but you
diff --git a/config/test.exs b/config/test.exs
index 718ffc7..caed05b 100644
--- a/config/test.exs
+++ b/config/test.exs
@@ -22,6 +22,9 @@ config :cannery, CanneryWeb.Endpoint,
 # In test we don't send emails.
 config :cannery, Cannery.Mailer, adapter: Swoosh.Adapters.Test
 
+# Don't require invites for signups
+config :cannery, Cannery.Accounts, registration: "public"
+
 # Print only warnings and errors during test
 config :logger, level: :warn
 
diff --git a/lib/cannery/accounts.ex b/lib/cannery/accounts.ex
index fbe31e1..71f4517 100644
--- a/lib/cannery/accounts.ex
+++ b/lib/cannery/accounts.ex
@@ -117,6 +117,8 @@ defmodule Cannery.Accounts do
       :passed
 
   """
+  @spec register_user(attrs :: map()) ::
+          {:ok, User.t()} | {:error, :invalid_token | User.changeset()}
   @spec register_user(attrs :: map(), Invite.token() | nil) ::
           {:ok, User.t()} | {:error, :invalid_token | User.changeset()}
   def register_user(attrs, invite_token \\ nil) do
diff --git a/lib/cannery/accounts/invites.ex b/lib/cannery/accounts/invites.ex
index 88be85e..7f8e955 100644
--- a/lib/cannery/accounts/invites.ex
+++ b/lib/cannery/accounts/invites.ex
@@ -85,7 +85,9 @@ defmodule Cannery.Accounts.Invites do
     end
   end
 
-  @spec get_invite_by_token(Invite.token()) :: {:ok, Invite.t()} | {:error, :invalid_token}
+  @spec get_invite_by_token(Invite.token() | nil) :: {:ok, Invite.t()} | {:error, :invalid_token}
+  defp get_invite_by_token(token) when token in [nil, ""], do: {:error, :invalid_token}
+
   defp get_invite_by_token(token) do
     Repo.one(
       from i in Invite,