diff --git a/lib/utopia/controller/respond.rb b/lib/utopia/controller/respond.rb
index 17e32a21..3ee21b3f 100644
--- a/lib/utopia/controller/respond.rb
+++ b/lib/utopia/controller/respond.rb
@@ -26,8 +26,6 @@ def responds
 					@responder ||= Responder.new
 				end
 				
-				alias respond responds
-				
 				# Serialize a semantic value according to the request's accepted media types.
 				# @parameter context [Controller::Base] The controller context.
 				# @parameter request [Utopia::Request] The request.
diff --git a/lib/utopia/controller/responder.rb b/lib/utopia/controller/responder.rb
index b62581df..929225b4 100644
--- a/lib/utopia/controller/responder.rb
+++ b/lib/utopia/controller/responder.rb
@@ -5,25 +5,23 @@
 
 require_relative "middleware"
 
+require "protocol/http/header/accept"
+require "protocol/media/map"
+require "protocol/media/type"
+require "protocol/media/range"
+
 module Utopia
 	module Controller
 		# @namespace
 		module Handlers
 			# Serializes controller values as JSON responses.
 			module JSON
-				APPLICATION_JSON = HTTP::Accept::ContentType.new("application", "json").freeze
-				
-				# Delegate content-type splitting to the JSON media type.
-				# @parameter arguments [Array] The arguments.
-				# @returns [Array] The resulting values.
-				def self.split(*arguments)
-					APPLICATION_JSON.split(*arguments)
-				end
+				APPLICATION_JSON = Protocol::Media::Type.new("application", "json").freeze
 				
 				# Serialize an object as JSON.
 				# @parameter context [Object] The context.
 				# @parameter request [Utopia::Request] The request.
-				# @parameter media_range [HTTP::Accept::MediaTypes::MediaRange] The negotiated media range.
+				# @parameter media_range [Protocol::HTTP::Header::Accept::MediaRange] The negotiated media range.
 				# @parameter object [Object] The object.
 				# @parameter options [Hash] The options.
 				# @returns [String] The serialized JSON body.
@@ -36,7 +34,7 @@ def self.call(context, request, media_range, object, **options)
 				end
 				
 				# The media type produced by this handler.
-				# @returns [HTTP::Accept::ContentType] The JSON media type.
+				# @returns [Protocol::Media::Type] The JSON media type.
 				def self.content_type
 					APPLICATION_JSON
 				end
@@ -44,19 +42,12 @@ def self.content_type
 			
 			# Passes response values through without transformation.
 			module Passthrough
-				WILDCARD = HTTP::Accept::MediaTypes::MediaRange.new("*", "*").freeze
-				
-				# Delegate content-type splitting to the wildcard media range.
-				# @parameter arguments [Array] The arguments.
-				# @returns [Array] The resulting values.
-				def self.split(*arguments)
-					WILDCARD.split(*arguments)
-				end
+				WILDCARD = Protocol::Media::Range.new("*", "*").freeze
 				
 				# Pass an object through without transformation.
 				# @parameter context [Object] The context.
 				# @parameter request [Utopia::Request] The request.
-				# @parameter media_range [HTTP::Accept::MediaTypes::MediaRange] The negotiated media range.
+				# @parameter media_range [Protocol::HTTP::Header::Accept::MediaRange] The negotiated media range.
 				# @parameter object [Object] The object.
 				# @parameter options [Hash] The options.
 				# @returns [Object] The original body.
@@ -76,17 +67,10 @@ def self.content_type
 		class Responder
 			# A content-type handler and its response block.
 			Handler = Struct.new(:content_type, :block) do
-				# Delegate content-type splitting to this handler's content type.
-				# @parameter arguments [Array] The arguments.
-				# @returns [Array] The resulting values.
-				def split(*arguments)
-					self.content_type.split(*arguments)
-				end
-				
 				# Invoke this handler's block in the controller context.
 				# @parameter context [Object] The context.
 				# @parameter request [Utopia::Request] The request.
-				# @parameter media_range [HTTP::Accept::MediaTypes::MediaRange] The negotiated media range.
+				# @parameter media_range [Protocol::HTTP::Header::Accept::MediaRange] The negotiated media range.
 				# @parameter arguments [Array] The arguments.
 				# @parameter options [Hash] The options.
 				# @returns [Object] The handler block's result.
@@ -95,65 +79,85 @@ def call(context, request, media_range, *arguments, **options)
 				end
 			end
 			
-			# Initialize an empty content-type handler map.
-			def initialize
-				@handlers = HTTP::Accept::MediaTypes::Map.new
+			# Initialize a responder with a handler map.
+			# @parameter handlers [Protocol::Media::Map] The response handlers.
+			# @parameter passthrough [Object | Nil] The fallback response handler.
+			def initialize(handlers = Protocol::Media::Map.new, passthrough = nil)
+				@handlers = handlers
+				@passthrough = passthrough
 			end
 			
 			attr :handlers
 			
-			# Freeze this object and its internal state.
-			# @returns [self] This object.
+			# Freeze this responder and compile its handler map.
+			# @returns [self] This responder.
 			def freeze
-				@handlers.freeze
-				
-				super
-			end
-			
-			# Negotiate the request's accepted media types and invoke the best handler.
-			# @parameter context [Object] The controller context.
-			# @parameter request [Utopia::Request] The request.
-			# @parameter arguments [Array] The arguments.
-			# @parameter options [Hash] The options.
-			# @returns [Array(Object, Object) | Nil] The selected content type and body, or `nil` if none matches.
-			def call(context, request, *arguments, **options)
-				# Parse the list of browser preferred content types and return ordered by priority:
-				media_types = HTTP::Accept::MediaTypes.browser_preferred_media_types(
-					HTTP::Accept::MediaTypes::HTTP_ACCEPT => Array(request.headers["accept"]).join(",")
-				)
+				return self if frozen?
 				
-				handler, media_range = @handlers.for(media_types)
-				
-				if handler
-					return handler.content_type, handler.call(context, request, media_range, *arguments, **options)
-				end
+				@handlers.freeze
 				
-				return nil
+				return super
 			end
 			
 			# Add a serializer for the specified content type.
+			# @parameter content_type [String | Protocol::Media::Type] The produced media type.
+			# @yields The response handler body.
+			# @returns [self] This responder.
 			def handle(content_type, &block)
-				@handlers << Handler.new(content_type, block)
+				@handlers[content_type] = Handler.new(content_type, block).freeze
+				return self
 			end
 			
 			# Register the default JSON handler.
-			# @returns [HTTP::Accept::MediaTypes::Map] The updated handler map.
+			# @returns [self] This responder.
 			def with_json
-				@handlers << Handlers::JSON
+				@handlers[Handlers::JSON::APPLICATION_JSON] = Handlers::JSON
+				return self
 			end
 			
 			# Register the wildcard passthrough handler.
-			# @returns [HTTP::Accept::MediaTypes::Map] The updated handler map.
+			# @returns [self] This responder.
 			def with_passthrough
-				@handlers << Handlers::Passthrough
+				@passthrough = Handlers::Passthrough
+				return self
 			end
 			
-			# Invoke the responder with the given object.
-			# @parameter content_type [String] The content type.
+			# Add a serializer for the specified content type.
+			# @parameter content_type [String | Protocol::Media::Type] The produced media type.
 			# @yields The response handler body.
-			# @returns [HTTP::Accept::MediaTypes::Map] The updated handler map.
+			# @returns [self] This responder.
 			def with(content_type, &block)
-				handle(content_type, &block)
+				return handle(content_type, &block)
+			end
+			
+			# Negotiate the request's accepted media types and invoke the best handler.
+			# @parameter context [Object] The controller context.
+			# @parameter request [Utopia::Request] The request.
+			# @parameter arguments [Array] The arguments.
+			# @parameter options [Hash] The options.
+			# @returns [Array(Object, Object) | Nil] The selected content type and body, or `nil` if none matches.
+			def call(context, request, *arguments, **options)
+				accept = request.headers["accept"]
+				
+				# An absent or empty Accept header accepts any media type:
+				if accept.nil? || accept.empty?
+					media_ranges = [Handlers::Passthrough::WILDCARD]
+				else
+					media_ranges = accept.preferred_media_ranges
+				end
+				
+				if match = @handlers.for(media_ranges)
+					handler, media_range = match
+				elsif @passthrough
+					handler = @passthrough
+					media_range = media_ranges.first
+				end
+				
+				if handler
+					return handler.content_type, handler.call(context, request, media_range, *arguments, **options)
+				end
+				
+				return nil
 			end
 		end
 	end
diff --git a/lib/utopia/http.rb b/lib/utopia/http.rb
index d63f31c6..f4fb7a93 100644
--- a/lib/utopia/http.rb
+++ b/lib/utopia/http.rb
@@ -3,15 +3,11 @@
 # Released under the MIT License.
 # Copyright, 2010-2026, by Samuel Williams.
 
-require "http/accept"
 require "protocol/http/status"
 
 module Utopia
 	# HTTP protocol implementation.
 	module HTTP
-		# Pull in {::HTTP::Accept} for parsing.
-		Accept = ::HTTP::Accept
-		
 		# A list of commonly used HTTP status codes.
 		# For help choosing the right status code, see http://racksburg.com/choosing-an-http-status-code/
 		STATUS_CODES = {
diff --git a/lib/utopia/localization.rb b/lib/utopia/localization.rb
index 3bcc20dd..2f6e90fc 100644
--- a/lib/utopia/localization.rb
+++ b/lib/utopia/localization.rb
@@ -4,6 +4,7 @@
 # Copyright, 2009-2025, by Samuel Williams.
 
 require_relative "localization/preferences"
+require_relative "localization/locales"
 require_relative "localization/resolver"
 require_relative "localization/middleware"
 
diff --git a/lib/utopia/localization/locales.rb b/lib/utopia/localization/locales.rb
new file mode 100644
index 00000000..46435897
--- /dev/null
+++ b/lib/utopia/localization/locales.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2026, by Samuel Williams.
+
+module Utopia
+	module Localization
+		# Matches configured locales against language ranges.
+		class Locales
+			# Expand a locale into progressively less specific language ranges.
+			# @parameter locale [String] The locale to expand.
+			# @parameter patterns [Hash] The destination language-range mapping.
+			def self.expand(locale, patterns)
+				parts = locale.split("-")
+				
+				while parts.any?
+					pattern = parts.join("-")
+					patterns[pattern] ||= locale
+					parts.pop
+				end
+			end
+			
+			# Initialize the configured locales.
+			# @parameter names [Array(String)] The locale names, in preference order.
+			def initialize(names)
+				@names = names
+				@patterns = {}
+				
+				@names.each do |name|
+					self.class.expand(name, @patterns)
+				end
+				
+				freeze
+			end
+			
+			# Freeze this object and its internal state.
+			# @returns [self] This object.
+			def freeze
+				return self if frozen?
+				
+				@names.freeze
+				@patterns.freeze
+				
+				return super
+			end
+			
+			attr :names
+			attr :patterns
+			
+			# Select configured locales matching the given language ranges.
+			# @parameter languages [Enumerable] Preferred language ranges.
+			# @returns [Array(String)] Matching locale names in language preference order.
+			def match(languages)
+				languages.filter_map do |language|
+					@patterns[language.name]
+				end
+			end
+		end
+	end
+end
diff --git a/lib/utopia/localization/middleware.rb b/lib/utopia/localization/middleware.rb
index 1024bc0b..579401eb 100644
--- a/lib/utopia/localization/middleware.rb
+++ b/lib/utopia/localization/middleware.rb
@@ -4,11 +4,13 @@
 # Copyright, 2025-2026, by Samuel Williams.
 
 require_relative "preferences"
+require_relative "locales"
 require_relative "../middleware"
 require_relative "../request"
 require_relative "../response"
 
 require "set"
+require "protocol/http/header/accept_language"
 
 module Utopia
 	module Localization
@@ -22,7 +24,7 @@ class Middleware < Protocol::HTTP::Middleware
 			def initialize(app, locales:, default_locale: nil, default_locales: nil, hosts: {}, ignore: [])
 				super(app)
 				
-				@all_locales = HTTP::Accept::Languages::Locales.new(locales)
+				@all_locales = Locales.new(locales)
 				
 				# Locales here are represented as an array of strings, e.g. ['en', 'ja', 'cn', 'de'] and are used in order if no locale is specified by the user.
 				unless @default_locales = default_locales
@@ -125,17 +127,17 @@ def extract_path_locale(request)
 			# @parameter request [Utopia::Request] The application request.
 			# @returns [Array(String)] Supported locales accepted by the browser, in preference order.
 			def browser_preferred_locales(request)
-				accept_languages = request.headers["accept-language"]&.to_s
+				accept_languages = request.headers["accept-language"]
 				
 				# No user prefered languages:
 				return [] unless accept_languages
 				
 				# Extract the ordered list of languages:
-				languages = HTTP::Accept::Languages.parse(accept_languages)
+				languages = accept_languages.preferred_languages
 				
 				# Returns available languages based on the order languages:
-				return @all_locales & languages
-			rescue HTTP::Accept::ParseError
+				return @all_locales.match(languages)
+			rescue Protocol::HTTP::Header::AcceptLanguage::ParseError
 				# If we fail to parse the browser Accept-Language header, we ignore it (silently).
 				return []
 			end
diff --git a/readme.md b/readme.md
index 911e964c..2df75f81 100644
--- a/readme.md
+++ b/readme.md
@@ -57,7 +57,6 @@ Please see the [project releases](https://socketry.github.io/utopia/releases/ind
   - [Utopia::Gallery](https://github.com/ioquatix/utopia-gallery) — A fast photo gallery based on [libvips](https://github.com/jcupitt/libvips).
   - [Utopia::Project](https://github.com/socketry/utopia-project) — A Ruby project documentation tool.
   - [Utopia::Analytics](https://github.com/ioquatix/utopia-analytics) — Simple integration with Google Analytics.
-  - [HTTP::Accept](https://github.com/ioquatix/http-accept) — RFC compliant header parser.
   - [Samovar](https://github.com/ioquatix/samovar) — Command line parser used by Utopia.
   - [Mapping](https://github.com/ioquatix/mapping) — Provide structured conversions for web interfaces.
 
diff --git a/releases.md b/releases.md
index e166e495..f1f0e85b 100644
--- a/releases.md
+++ b/releases.md
@@ -3,6 +3,7 @@
 ## Unreleasd
 
   - **Security** Fix handling of redirects that start with `//` to prevent open redirect vulnerabilities.
+  - Use `protocol-media` and `protocol-http` for response and language negotiation, removing the `http-accept` dependency.
 
 ## v2.31.0
 
diff --git a/setup/site/pages/welcome/index.xnode b/setup/site/pages/welcome/index.xnode
index 91bbc44a..3e8b08c0 100644
--- a/setup/site/pages/welcome/index.xnode
+++ b/setup/site/pages/welcome/index.xnode
@@ -17,7 +17,7 @@
 		<div>
 			<i class="fa fa-code"></i>
 			<h2>Well tested and maintained</h2>
-			<p>Utopia comprises a <a href="https://github.com/ioquatix/utopia">core gem</a> and several supporting libraries, the main ones being <a href="https://github.com/ioquatix/trenni">trenni</a> for templates and parsing, and <a href="https://github.com/ioquatix/http-accept">http-accept</a> for HTTP header processing. Together, these gems have over 90% test coverage.</p>
+			<p>Utopia comprises a <a href="https://github.com/ioquatix/utopia">core gem</a> and several supporting libraries, including <a href="https://github.com/socketry/xrb">XRB</a> for templates and markup parsing and <a href="https://github.com/socketry/protocol-http">Protocol HTTP</a> for HTTP protocol handling.</p>
 		</div>
 		
 		<div>
diff --git a/test/utopia/.performance/pages/api/controller.rb b/test/utopia/.performance/pages/api/controller.rb
index e8fb742e..6caf5f3e 100644
--- a/test/utopia/.performance/pages/api/controller.rb
+++ b/test/utopia/.performance/pages/api/controller.rb
@@ -4,7 +4,7 @@
 # Copyright, 2016-2023, by Samuel Williams.
 
 prepend Respond, Actions
-respond.with_json
+responds.with_json
 
 on 'fetch' do
 	succeed! [1, 2, 3]
diff --git a/test/utopia/controller/.respond/api/controller.rb b/test/utopia/controller/.respond/api/controller.rb
index 07c5ce46..02696256 100644
--- a/test/utopia/controller/.respond/api/controller.rb
+++ b/test/utopia/controller/.respond/api/controller.rb
@@ -4,7 +4,7 @@
 # Copyright, 2016-2023, by Samuel Williams.
 
 prepend Respond, Actions
-respond.with_json
+responds.with_json
 
 class VersionedResponse
 	def to_json(options = {})
diff --git a/test/utopia/controller/.respond/html/controller.rb b/test/utopia/controller/.respond/html/controller.rb
index 4bb85e8d..8343fc63 100644
--- a/test/utopia/controller/.respond/html/controller.rb
+++ b/test/utopia/controller/.respond/html/controller.rb
@@ -6,7 +6,7 @@
 prepend Respond, Actions
 
 # Respond with json:
-respond.with_json
+responds.with_json
 
 # This method should return HTML, even thought this controller responds with JSON.
 on 'hello-world' do
diff --git a/test/utopia/controller/.respond/rewrite/controller.rb b/test/utopia/controller/.respond/rewrite/controller.rb
index 0bb37a5c..46ead6d9 100644
--- a/test/utopia/controller/.respond/rewrite/controller.rb
+++ b/test/utopia/controller/.respond/rewrite/controller.rb
@@ -5,7 +5,7 @@
 
 prepend Respond, Rewrite, Actions
 
-respond.with_json
+responds.with_json
 
 rewrite.extract_prefix id: Integer do |request|
 	fail! :not_found, message: "Could not find record" if @id == 1
diff --git a/test/utopia/controller/.websocket/server/controller.rb b/test/utopia/controller/.websocket/server/controller.rb
index 87f59124..fddbfc6d 100644
--- a/test/utopia/controller/.websocket/server/controller.rb
+++ b/test/utopia/controller/.websocket/server/controller.rb
@@ -5,7 +5,7 @@
 
 prepend Respond, Actions
 
-respond.with_passthrough
+responds.with_passthrough
 
 on 'events' do |request|
 	upgrade = Async::WebSocket::Adapters::HTTP.open(request) do |connection|
diff --git a/test/utopia/controller/respond.rb b/test/utopia/controller/respond.rb
index 6d2d2c56..e444f937 100644
--- a/test/utopia/controller/respond.rb
+++ b/test/utopia/controller/respond.rb
@@ -46,6 +46,8 @@ def self.uri_path
 		end
 	end
 	
+	TestController.freeze
+	
 	let(:controller) {TestController.new}
 	
 	def mock_request(path, headers = {})
@@ -86,6 +88,24 @@ def mock_request(path, headers = {})
 		expect(response.read).to be == '{"user_id":10}'
 	end
 	
+	it "preserves the requested order for equally preferred responses" do
+		request, path = mock_request("/fetch", {"accept" => "text/plain, application/json"})
+		relative_path = path - controller.class.uri_path
+		
+		response = controller.process!(request, relative_path)
+		
+		expect(response.headers["content-type"]).to be == "text/plain"
+	end
+	
+	it "treats an empty accept header as accepting any response" do
+		request, path = mock_request("/fetch", {"accept" => ""})
+		relative_path = path - controller.class.uri_path
+		
+		response = controller.process!(request, relative_path)
+		
+		expect(response.headers["content-type"]).to be == "application/json"
+	end
+	
 	it "preserves readable response bodies" do
 		body = Protocol::HTTP::Body::Readable.new
 		controller.instance_variable_set(:@stream, body)
@@ -117,6 +137,14 @@ def mock_request(path, headers = {})
 		expect(response.read).to be == "Explicit"
 	end
 	
+	it "falls back to the passthrough handler" do
+		responder = Utopia::Controller::Responder.new
+		responder.with_passthrough
+		responder.freeze
+		request = Utopia::Request["GET", "/", {"accept" => "application/xml"}]
+		
+		expect(responder.call(controller, request, "Hello World")).to be == [nil, "Hello World"]
+	end
 end
 
 describe Utopia::Controller do
diff --git a/test/utopia/localization.rb b/test/utopia/localization.rb
index b6df428f..cd43e545 100755
--- a/test/utopia/localization.rb
+++ b/test/utopia/localization.rb
@@ -76,6 +76,24 @@
 		expect(last_response.headers["content-location"].to_s).to be == "/ja/localized.txt"
 	end
 	
+	it "matches less specific accepted languages" do
+		application = Utopia::Application.build(Protocol::HTTP::Middleware.for do |request|
+			Utopia::Response.text(request.localization.preferred_locales.compact.join(","))
+		end) do
+			use Utopia::Localization, locales: ["en-NZ", "en-US"], default_locale: "en-NZ"
+		end
+		
+		response = application.call(Protocol::HTTP::Request["GET", "/", {"accept-language" => "en"}])
+		
+		expect(response.read).to be == "en-NZ"
+	end
+	
+	it "ignores malformed accepted languages" do
+		client.get "/localized.txt", {"accept-language" => "not a language"}
+		
+		expect(last_response.read).to be == "localized.en.txt"
+	end
+	
 	it "resolves localized content templates" do
 		client.get "/page", {"accept-language" => "ja,en"}
 		
diff --git a/utopia.gemspec b/utopia.gemspec
index 2fcfb842..297b27c2 100644
--- a/utopia.gemspec
+++ b/utopia.gemspec
@@ -28,14 +28,14 @@ Gem::Specification.new do |spec|
 	spec.add_dependency "bake", "~> 0.20"
 	spec.add_dependency "concurrent-ruby", "~> 1.2"
 	spec.add_dependency "console", "~> 1.24"
-	spec.add_dependency "http-accept", "~> 2.1"
 	spec.add_dependency "irb"
 	spec.add_dependency "mail", "~> 2.6"
 	spec.add_dependency "mime-types", "~> 3.0"
 	spec.add_dependency "msgpack"
 	spec.add_dependency "net-smtp"
 	spec.add_dependency "protocol-content", "~> 0.1"
-	spec.add_dependency "protocol-http", "~> 0.68"
+	spec.add_dependency "protocol-http", "~> 0.70"
+	spec.add_dependency "protocol-media", "~> 0.3"
 	spec.add_dependency "protocol-url", "~> 0.10"
 	spec.add_dependency "samovar", "~> 2.1"
 	spec.add_dependency "traces", "~> 0.10"