diff --git a/custom-pkgs/default.nix b/custom-pkgs/default.nix
index 576d568..ba7207b 100644
--- a/custom-pkgs/default.nix
+++ b/custom-pkgs/default.nix
@@ -18,7 +18,7 @@ lib.composeManyExtensions (
     dir:
     import ./${dir} {
       util = util dir;
-      inherit inputs pkgs-unstable;
+      inherit inputs lib pkgs-unstable;
     }
   ) dirs
 )
diff --git a/custom-pkgs/otp/default.nix b/custom-pkgs/otp/default.nix
index 84e5e76..c82c25b 100644
--- a/custom-pkgs/otp/default.nix
+++ b/custom-pkgs/otp/default.nix
@@ -1 +1,7 @@
-{ util, pkgs-unstable, ... }: util.package { inherit pkgs-unstable; }
+{
+  util,
+  pkgs-unstable,
+  lib,
+  ...
+}:
+util.package { inherit pkgs-unstable lib; }
diff --git a/custom-pkgs/otp/otp.cr b/custom-pkgs/otp/otp.cr
new file mode 100644
index 0000000..863bf11
--- /dev/null
+++ b/custom-pkgs/otp/otp.cr
@@ -0,0 +1,96 @@
+require "option_parser"
+
+NOTIFY_ICON         = {{env("NOTIFY_ICON")}}
+NOTIFY_SEND_COMMAND = {{env("NOTIFY_SEND")}}
+WL_COPY_COMMAND     = {{env("WL_COPY")}}
+YKMAN_COMMAND       = {{env("YKMAN")}}
+SKIM_COMMAND        = {{env("SKIM")}}
+WALKER_COMMAND      = {{env("WALKER")}}
+
+class OTP
+  private property dmenu_command : String = SKIM_COMMAND
+  private property dmenu_args = [] of String
+
+  def run
+    parser = OptionParser.new do |opts|
+      opts.banner = "Usage: #{PROGRAM_NAME} [options]"
+
+      opts.on("-h", "--help", "Display this help message") do
+        puts opts
+        exit
+      end
+
+      opts.on("-w", "--walker", "Use walker as dmenu") do
+        self.dmenu_command = WALKER_COMMAND
+        self.dmenu_args << "--dmenu" << "-p" << "Select account:"
+      end
+    end
+
+    parser.parse
+
+    self.dmenu_args += ["-q", *ARGV] unless ARGV.empty?
+
+    account = select_account
+    code = code_for(account)
+    copy(code)
+  end
+
+  private def notify_send(message, urgency = :normal)
+    return if message.chomp.empty?
+
+    Process.run(NOTIFY_SEND_COMMAND, ["-i", NOTIFY_ICON, "-u", urgency.to_s, "OTP", message.chomp])
+  end
+
+  private def list_accounts
+    error = IO::Memory.new
+    output = IO::Memory.new
+    status = Process.run(YKMAN_COMMAND, %w[oath accounts list], output: output, error: error)
+    errors = error.rewind.gets_to_end.try(&.chomp)
+    notify_send(errors, urgency: status.success? ? :normal : :critical) unless errors.empty?
+    exit status.exit_code unless status.success?
+
+    output.rewind.gets_to_end
+  end
+
+  private def select_account
+    output = IO::Memory.new
+    accounts = list_accounts
+    puts accounts
+    input = IO::Memory.new(accounts)
+    Process.run(dmenu_command, dmenu_args, output: output, input: input)
+
+    account = output.rewind.gets(chomp: true)
+    return account if account
+
+    notify_send("No account selected", urgency: :critical)
+    exit 1
+  end
+
+  private def code_for(account)
+    output = IO::Memory.new
+
+    Process.run(YKMAN_COMMAND, ["oath", "accounts", "code", "-s", account], output: output) do |process|
+      spawn do
+        while line = process.error.gets(chomp: true)
+          notify_send(line)
+        end
+      end
+    end
+
+    exit $?.exit_code unless $?.success?
+
+    code = output.rewind.gets(chomp: true)
+    return code if code
+
+    notify_send("No code generated", urgency: :critical)
+    exit 1
+  end
+
+  private def copy(code)
+    input = IO::Memory.new(code)
+    Process.run(WL_COPY_COMMAND, %w[-n], input: input)
+    notify_send("Copied to clipboard")
+  end
+end
+
+OTP.new.run
diff --git a/custom-pkgs/otp/package.nix b/custom-pkgs/otp/package.nix
index 489fc19..0cfc6e3 100644
--- a/custom-pkgs/otp/package.nix
+++ b/custom-pkgs/otp/package.nix
@@ -1,18 +1,22 @@
-{ pkgs, pkgs-unstable }:
-let
-  yubikey-manager = pkgs-unstable.yubikey-manager;
-  ykman = "${yubikey-manager}/bin/ykman";
-  sk = "${pkgs.skim}/bin/sk";
-  wl-copy = "${pkgs.wl-clipboard}/bin/wl-copy";
-in
-pkgs.writeShellScriptBin "otp" ''
-  skim_command=("${sk}")
-
-  if [ -n "$*" ]; then
-    skim_command+=(-q "$*")
-  fi
-
-  account=$(${ykman} oath accounts list | "''${skim_command[@]}")
-  [ -z "$account" ] && exit 1
-  ${ykman} oath accounts code -s "$account" | ${wl-copy} -n
-''
+{
+  pkgs,
+  lib,
+  pkgs-unstable,
+}:
+pkgs.runCommand "otp"
+  {
+    code = ./otp.cr;
+    env = {
+      YKMAN = lib.getExe pkgs-unstable.yubikey-manager;
+      SKIM = lib.getExe pkgs.skim;
+      WALKER = lib.getExe pkgs-unstable.walker;
+      WL_COPY = lib.getExe' pkgs.wl-clipboard "wl-copy";
+      NOTIFY_SEND = lib.getExe pkgs.libnotify;
+      NOTIFY_ICON = "${pkgs-unstable.yubioath-flutter}/share/pixmaps/com.yubico.yubioath.png";
+    };
+    nativeBuildInputs = [ pkgs.crystal ];
+  }
+  ''
+    mkdir -p $out/bin
+    crystal build $code --release -o $out/bin/otp
+  ''