diff --git a/bin/lively b/bin/lively
index 39268b1..c1e9d71 100755
--- a/bin/lively
+++ b/bin/lively
@@ -2,6 +2,7 @@
 # frozen_string_literal: true
 
 require "async/service"
+require "async/container/threaded"
 require_relative "../lib/lively/environment/application"
 
 ARGV.each do |path|
@@ -11,7 +12,7 @@ end
 configuration = Async::Service::Configuration.build do
 	service "lively" do
 		include Lively::Environment::Application
-	end	
+	end
 end
 
-Async::Service::Controller.run(configuration)
+Async::Service::Controller.run(configuration, container_class: Async::Container::Threaded)
diff --git a/lib/lively/assets.rb b/lib/lively/assets.rb
index 7d1097e..881ddc6 100644
--- a/lib/lively/assets.rb
+++ b/lib/lively/assets.rb
@@ -3,6 +3,7 @@
 # Released under the MIT License.
 # Copyright, 2021-2025, by Samuel Williams.
 
+require "uri"
 require "protocol/http/middleware"
 require "protocol/http/body/file"
 require "console"
diff --git a/lib/lively/environment/application.rb b/lib/lively/environment/application.rb
index 5f6ac95..f5a22dd 100644
--- a/lib/lively/environment/application.rb
+++ b/lib/lively/environment/application.rb
@@ -1,56 +1,68 @@
 # frozen_string_literal: true
 
 # Released under the MIT License.
-# Copyright, 2021-2025, by Samuel Williams.
+# Copyright, 2021-2026, by Samuel Williams.
 
-require_relative "../application"
-require_relative "../assets"
-
-require "falcon/environment/server"
+require_relative "middleware"
+require_relative "http"
+require_relative "htty"
 
 # @namespace
 module Lively
 	# @namespace
 	module Environment
-		# Represents the environment configuration for a Lively application server.
-		# 
-		# This module provides server configuration including URL binding, process count,
-		# application class resolution, and middleware stack setup. It integrates with
-		# Falcon's server environment to provide a complete hosting solution.
+		# Multiplexing environment for Lively applications.
+		#
+		# Declares the transport selection as explicit, overridable evaluator keys and uses `make_service` to compose the appropriate child environment at service startup time. This keeps transport selection in the service layer rather than in module inclusion hooks.
+		#
+		# The `htty` key controls which transport is used. Override it in a service block to force a specific transport regardless of the environment variable:
+		#
+		# ~~~ ruby
+		# service "myapp" do
+		#   include Lively::Environment::Application
+		#   def htty = false  # always use HTTP
+		# end
+		# ~~~
 		module Application
-			include Falcon::Environment::Server
+			include Lively::Environment::Middleware
+			# Note: does not include Falcon::Environment::Server directly. Falcon is
+			# brought in exclusively via http_environment so that the combined
+			# evaluator's service_class resolves correctly without shadowing.
+			
+			# Whether to use HTTY transport. Reads ENV["HTTY"] by default.
+			# @returns [Boolean]
+			def htty
+				ENV["HTTY"] == "1"
+			end
 			
-			# Get the server URL for this application.
-			# @returns [String] The base URL where the server will be accessible.
-			def url
-				"http://localhost:9292"
+			# The environment module to use for HTTY transport.
+			# @returns [Module]
+			def htty_environment
+				Lively::Environment::HTTY
 			end
 			
-			# Get the number of server processes to run.
-			# @returns [Integer] The number of worker processes.
-			def count
-				1
+			# The environment module to use for HTTP transport.
+			# @returns [Module]
+			def http_environment
+				Lively::Environment::HTTP
 			end
 			
-			# Resolve the application class to use.
-			# @returns [Class] The application class, either user-defined or default.
-			def application
-				if Object.const_defined?(:Application)
-					Object.const_get(:Application)
-				else
-					Console.warn(self, "No Application class defined, using default.")
-					::Lively::Application
-				end
+			# The environment module for the selected transport.
+			# @returns [Module]
+			def transport_environment
+				htty ? htty_environment : http_environment
 			end
 			
-			# Build the middleware stack for this application.
-			# @returns [Protocol::HTTP::Middleware] The complete middleware stack.
-			def middleware
-				::Protocol::HTTP::Middleware.build do |builder|
-					builder.use Lively::Assets, root: File.expand_path("public", self.root)
-					builder.use Lively::Assets, root: File.expand_path("../../../public", __dir__)
-					builder.use self.application
-				end
+			# Build the service by composing the transport environment on top of this one.
+			# Called by Async::Service::Generic.wrap — self is the evaluator at call time.
+			# @parameter environment [Async::Service::Environment]
+			# @returns [Async::Service::Generic]
+			def make_service(environment)
+				combined = environment.with(transport_environment)
+				combined_evaluator = combined.evaluator
+				
+				# Call `service_class.new` directly rather than `Async::Service::Generic.wrap` — the combined evaluator still has `Application` (and therefore `make_service`) in its ancestor chain, so `wrap` would recurse back into this method.
+				return combined_evaluator.service_class.new(combined, combined_evaluator)
 			end
 		end
 	end
diff --git a/lib/lively/environment/http.rb b/lib/lively/environment/http.rb
new file mode 100644
index 0000000..61a229e
--- /dev/null
+++ b/lib/lively/environment/http.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2021-2026, by Samuel Williams.
+
+require_relative "middleware"
+require "falcon/environment/server"
+
+# @namespace
+module Lively
+	# @namespace
+	module Environment
+		# Falcon (TCP/HTTP) environment for Lively applications.
+		#
+		# Combines {Falcon::Environment::Server} for HTTP transport with
+		# {Lively::Environment::Middleware} for application and asset serving.
+		module HTTP
+			include Falcon::Environment::Server
+			include Lively::Environment::Middleware
+			
+			# The URL this server binds to.
+			# @returns [String]
+			def url
+				ENV.fetch("LIVELY_URL", "http://localhost:9292")
+			end
+			
+			# The number of worker processes/threads to run.
+			# @returns [Integer]
+			def count
+				1
+			end
+		end
+	end
+end
diff --git a/lib/lively/environment/htty.rb b/lib/lively/environment/htty.rb
new file mode 100644
index 0000000..c652035
--- /dev/null
+++ b/lib/lively/environment/htty.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2026, by Samuel Williams.
+
+require_relative "middleware"
+require "async/htty/environment/server"
+
+# @namespace
+module Lively
+	# @namespace
+	module Environment
+		# HTTY (terminal side-channel) environment for Lively applications.
+		#
+		# Combines {Async::HTTY::Environment} for HTTY transport with
+		# {Lively::Environment::Middleware} for application and asset serving.
+		module HTTY
+			include Async::HTTY::Environment::Server
+			include Lively::Environment::Middleware
+		end
+	end
+end
diff --git a/lib/lively/environment/middleware.rb b/lib/lively/environment/middleware.rb
new file mode 100644
index 0000000..c36b6fd
--- /dev/null
+++ b/lib/lively/environment/middleware.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2021-2026, by Samuel Williams.
+
+require_relative "../application"
+require_relative "../assets"
+
+require "protocol/http/middleware/builder"
+
+# @namespace
+module Lively
+	# @namespace
+	module Environment
+		# Shared middleware configuration for Lively application environments.
+		#
+		# Provides the application class resolver, asset middleware, and the
+		# Lively middleware stack. Included by both {HTTP} and {HTTY} environments.
+		module Middleware
+			# Get the root directory for this application.
+			# @returns [String] The current working directory.
+			def root
+				Dir.pwd
+			end
+			
+			# Resolve the application class to use.
+			# @returns [Class] The application class, either user-defined or default.
+			def application
+				if Object.const_defined?(:Application)
+					Object.const_get(:Application)
+				else
+					Console.warn(self, "No Application class defined, using default.")
+					::Lively::Application
+				end
+			end
+			
+			# Build the middleware stack for this application.
+			# @returns [Protocol::HTTP::Middleware] The complete middleware stack.
+			def middleware
+				::Protocol::HTTP::Middleware.build do |builder|
+					builder.use Lively::Assets, root: File.expand_path("public", self.root)
+					builder.use Lively::Assets, root: File.expand_path("../../../public", __dir__)
+					builder.use self.application
+				end
+			end
+		end
+	end
+end
diff --git a/lively.gemspec b/lively.gemspec
index 2fab680..b85c483 100644
--- a/lively.gemspec
+++ b/lively.gemspec
@@ -27,6 +27,8 @@ Gem::Specification.new do |spec|
 	spec.required_ruby_version = ">= 3.3"
 	
 	spec.add_dependency "agent-context"
+	spec.add_dependency "async-htty"
+	spec.add_dependency "async-service", "~> 0.23"
 	spec.add_dependency "falcon", "~> 0.47"
 	spec.add_dependency "io-watch"
 	spec.add_dependency "live", "~> 0.18"
diff --git a/test/lively/environment/application.rb b/test/lively/environment/application.rb
index 5159180..4530521 100644
--- a/test/lively/environment/application.rb
+++ b/test/lively/environment/application.rb
@@ -13,23 +13,28 @@
 	let(:environment) {Async::Service::Environment.build(subject, root: __dir__)}
 	let(:evaluator) {environment.evaluator}
 	
-	with "module methods" do
-		it "provides default URL" do
-			expect(evaluator.url).to be == "http://localhost:9292"
+	with "transport selection" do
+		it "selects HTTP transport by default" do
+			expect(evaluator.transport_environment).to be == Lively::Environment::HTTP
 		end
 		
-		it "provides default count" do
-			expect(evaluator.count).to be == 1
+		it "selects HTTY transport when htty is true" do
+			environment = Async::Service::Environment.build(subject, root: __dir__) do
+				htty true
+			end
+			expect(environment.evaluator.transport_environment).to be == Lively::Environment::HTTY
 		end
+	end
+	
+	with "transport evaluator" do
+		let(:transport_evaluator) {environment.with(evaluator.transport_environment).evaluator}
 		
-		it "provides default application class" do
-			application_class = evaluator.application
-			expect(application_class).to be == Lively::Application
+		it "provides default URL" do
+			expect(transport_evaluator.url).to be == "http://localhost:9292"
 		end
 		
-		it "provides middleware stack" do
-			middleware = evaluator.middleware
-			expect(middleware).to be_a(Protocol::HTTP::Middleware)
+		it "provides default count" do
+			expect(transport_evaluator.count).to be == 1
 		end
 	end
 	
@@ -67,25 +72,8 @@
 	end
 	
 	with "middleware configuration" do
-		it "includes Assets middleware for public directory" do
-			middleware = evaluator.middleware
-			
-			# The middleware should be configured with Assets
-			expect(middleware).to be_a(Protocol::HTTP::Middleware)
-		end
-		
-		it "includes Assets middleware for gem public directory" do
-			middleware = evaluator.middleware
-			
-			# Should include the gem's public directory assets
-			expect(middleware).to be_a(Protocol::HTTP::Middleware)
-		end
-		
-		it "includes application middleware" do
-			middleware = evaluator.middleware
-			
-			# Should include the application class in the middleware stack
-			expect(middleware).to be_a(Protocol::HTTP::Middleware)
+		it "provides a middleware stack" do
+			expect(evaluator.middleware).to be_a(Protocol::HTTP::Middleware)
 		end
 	end
 end