diff --git a/cmd/tools/vtest-self.v b/cmd/tools/vtest-self.v
index 13f440a9bc..893e7444f7 100644
--- a/cmd/tools/vtest-self.v
+++ b/cmd/tools/vtest-self.v
@@ -264,8 +264,8 @@ const skip_on_ubuntu_musl = [
 	'vlib/net/smtp/smtp_test.v',
 	'vlib/v/tests/websocket_logger_interface_should_compile_test.v',
 	'vlib/v/tests/fn_literal_type_test.v',
-	'vlib/vweb/x/tests/vweb_test.v',
-	'vlib/vweb/x/tests/vweb_app_test.v',
+	'vlib/x/vweb/tests/vweb_test.v',
+	'vlib/x/vweb/tests/vweb_app_test.v',
 ]
 const skip_on_linux = [
 	'do_not_remove',
diff --git a/examples/pico/pico.v b/examples/pico/pico.v
index ca4b76f109..2dc64cb360 100644
--- a/examples/pico/pico.v
+++ b/examples/pico/pico.v
@@ -50,6 +50,6 @@ fn callback(data voidptr, req picohttpparser.Request, mut res picohttpparser.Res
 
 fn main() {
 	println('Starting webserver on http://localhost:${port}/ ...')
-	mut server := picoev.new(port: port, cb: callback)
+	mut server := picoev.new(port: port, cb: callback)!
 	server.serve()
 }
diff --git a/examples/pico/raw_callback.v b/examples/pico/raw_callback.v
index 181da7d0aa..4eb62ceb03 100644
--- a/examples/pico/raw_callback.v
+++ b/examples/pico/raw_callback.v
@@ -12,7 +12,7 @@ fn main() {
 	mut pico := picoev.new(
 		port: port
 		raw_cb: handle_conn
-	)
+	)!
 	pico.serve()
 }
 
diff --git a/vlib/picoev/picoev.v b/vlib/picoev/picoev.v
index 5a8024eb24..df328a4569 100644
--- a/vlib/picoev/picoev.v
+++ b/vlib/picoev/picoev.v
@@ -44,8 +44,8 @@ pub:
 	max_headers  int            = 100
 	max_read     int            = 4096
 	max_write    int            = 8192
-	family       net.AddrFamily = .ip
-	host         string = 'localhost'
+	family       net.AddrFamily = .ip6
+	host         string
 }
 
 @[heap]
@@ -302,8 +302,8 @@ fn default_err_cb(data voidptr, req picohttpparser.Request, mut res picohttppars
 }
 
 // new creates a `Picoev` struct and initializes the main loop
-pub fn new(config Config) &Picoev {
-	listen_fd := listen(config)
+pub fn new(config Config) !&Picoev {
+	listen_fd := listen(config)!
 
 	mut pv := &Picoev{
 		num_loops: 1
diff --git a/vlib/picoev/socket_util.c.v b/vlib/picoev/socket_util.c.v
index f90946b17c..7589da488e 100644
--- a/vlib/picoev/socket_util.c.v
+++ b/vlib/picoev/socket_util.c.v
@@ -99,7 +99,7 @@ fn fatal_socket_error(fd int) bool {
 }
 
 // listen creates a listening tcp socket and returns its file descriptor
-fn listen(config Config) int {
+fn listen(config Config) !int {
 	// not using the `net` modules sockets, because not all socket options are defined
 	fd := C.socket(config.family, net.SocketType.tcp, 0)
 	assert fd != -1
@@ -110,16 +110,23 @@ fn listen(config Config) int {
 
 	// Setting flags for socket
 	flag := 1
-	assert C.setsockopt(fd, C.SOL_SOCKET, C.SO_REUSEADDR, &flag, sizeof(int)) == 0
+	flag_zero := 0
+	net.socket_error(C.setsockopt(fd, C.SOL_SOCKET, C.SO_REUSEADDR, &flag, sizeof(int)))!
+
+	if config.family == .ip6 {
+		// set socket to dualstack so connections to both ipv4 and ipv6 addresses
+		// can be accepted
+		net.socket_error(C.setsockopt(fd, C.IPPROTO_IPV6, C.IPV6_V6ONLY, &flag_zero, sizeof(int)))!
+	}
 
 	$if linux {
 		// epoll socket options
-		assert C.setsockopt(fd, C.SOL_SOCKET, C.SO_REUSEPORT, &flag, sizeof(int)) == 0
-		assert C.setsockopt(fd, C.IPPROTO_TCP, C.TCP_QUICKACK, &flag, sizeof(int)) == 0
-		assert C.setsockopt(fd, C.IPPROTO_TCP, C.TCP_DEFER_ACCEPT, &config.timeout_secs,
-			sizeof(int)) == 0
+		net.socket_error(C.setsockopt(fd, C.SOL_SOCKET, C.SO_REUSEPORT, &flag, sizeof(int)))!
+		net.socket_error(C.setsockopt(fd, C.IPPROTO_TCP, C.TCP_QUICKACK, &flag, sizeof(int)))!
+		net.socket_error(C.setsockopt(fd, C.IPPROTO_TCP, C.TCP_DEFER_ACCEPT, &config.timeout_secs,
+			sizeof(int)))!
 		queue_len := max_queue
-		assert C.setsockopt(fd, C.IPPROTO_TCP, C.TCP_FASTOPEN, &queue_len, sizeof(int)) == 0
+		net.socket_error(C.setsockopt(fd, C.IPPROTO_TCP, C.TCP_FASTOPEN, &queue_len, sizeof(int)))!
 	}
 
 	// addr settings
@@ -128,12 +135,8 @@ fn listen(config Config) int {
 	addr := addrs[0]
 	alen := addr.len()
 
-	net.socket_error_message(C.bind(fd, voidptr(&addr), alen), 'binding to ${saddr} failed') or {
-		panic(err)
-	}
-	net.socket_error_message(C.listen(fd, C.SOMAXCONN), 'listening on ${saddr} with maximum backlog pending queue of ${C.SOMAXCONN}, failed') or {
-		panic(err)
-	}
+	net.socket_error_message(C.bind(fd, voidptr(&addr), alen), 'binding to ${saddr} failed')!
+	net.socket_error_message(C.listen(fd, C.SOMAXCONN), 'listening on ${saddr} with maximum backlog pending queue of ${C.SOMAXCONN}, failed')!
 
 	setup_sock(fd) or {
 		config.err_cb(config.user_data, picohttpparser.Request{}, mut &picohttpparser.Response{},
diff --git a/vlib/x/vweb/context.v b/vlib/x/vweb/context.v
index f4c44f20cb..a8b6909621 100644
--- a/vlib/x/vweb/context.v
+++ b/vlib/x/vweb/context.v
@@ -20,6 +20,7 @@ pub enum RedirectType {
 
 // The Context struct represents the Context which holds the HTTP request and response.
 // It has fields for the query, form, files and methods for handling the request and response
+@[heap]
 pub struct Context {
 mut:
 	// vweb wil try to infer the content type base on file extension,
@@ -120,29 +121,28 @@ pub fn (mut ctx Context) send_response_to_client(mimetype string, response strin
 	return Result{}
 }
 
-// Response HTTP_OK with s as payload with content-type `text/html`
+// Response with payload and content-type `text/html`
 pub fn (mut ctx Context) html(s string) Result {
 	return ctx.send_response_to_client('text/html', s)
 }
 
-// Response HTTP_OK with s as payload with content-type `text/plain`
+// Response with `s` as payload and content-type `text/plain`
 pub fn (mut ctx Context) text(s string) Result {
 	return ctx.send_response_to_client('text/plain', s)
 }
 
-// Response HTTP_OK with j as payload with content-type `application/json`
+// Response with json_s as payload and content-type `application/json`
 pub fn (mut ctx Context) json[T](j T) Result {
 	json_s := json.encode(j)
 	return ctx.send_response_to_client('application/json', json_s)
 }
 
-// Response HTTP_OK with a pretty-printed JSON result
+// Response with a pretty-printed JSON result
 pub fn (mut ctx Context) json_pretty[T](j T) Result {
 	json_s := json.encode_pretty(j)
 	return ctx.send_response_to_client('application/json', json_s)
 }
 
-// TODO - test + turn read_file into streaming
 // Response HTTP_OK with file as payload
 pub fn (mut ctx Context) file(file_path string) Result {
 	if !os.exists(file_path) {
@@ -187,10 +187,7 @@ fn (mut ctx Context) send_file(content_type string, file_path string) Result {
 	}
 	file.close()
 
-	// optimization: use max_read on purpose instead of max_write to take into account
-	// the HTTP header size and the fact that it's not likely that the socket/OS
-	// is able to write 8KB at once under load.
-	if file_size < max_read || ctx.takeover {
+	if ctx.takeover {
 		// it's a small file so we can send the response directly
 		data := os.read_file(file_path) or {
 			eprintln('[vweb] error while trying to read file: ${err.msg()}')
diff --git a/vlib/x/vweb/controller.v b/vlib/x/vweb/controller.v
index 0141f077f5..7e066a7467 100644
--- a/vlib/x/vweb/controller.v
+++ b/vlib/x/vweb/controller.v
@@ -2,7 +2,7 @@ module vweb
 
 import net.urllib
 
-type ControllerHandler = fn (ctx Context, mut url urllib.URL, host string) Context
+type ControllerHandler = fn (ctx &Context, mut url urllib.URL, host string) &Context
 
 pub struct ControllerPath {
 pub:
@@ -35,7 +35,7 @@ pub fn controller[A, X](path string, mut global_app A) !&ControllerPath {
 	// no need to type `ControllerHandler` as generic since it's not needed for closures
 	return &ControllerPath{
 		path: path
-		handler: fn [mut global_app, path, routes, controllers_sorted] [A, X](ctx Context, mut url urllib.URL, host string) Context {
+		handler: fn [mut global_app, path, routes, controllers_sorted] [A, X](ctx &Context, mut url urllib.URL, host string) &Context {
 			// transform the url
 			url.path = url.path.all_after_first(path)
 
@@ -53,7 +53,8 @@ pub fn controller[A, X](path string, mut global_app A) !&ControllerPath {
 			user_context.Context = ctx
 
 			handle_route[A, X](mut global_app, mut user_context, url, host, &routes)
-			return user_context.Context
+			// we need to explicitly tell the V compiler to return a reference
+			return &user_context.Context
 		}
 	}
 }
@@ -95,7 +96,7 @@ fn check_duplicate_routes_in_controllers[T](global_app &T, routes map[string]Rou
 	return controllers_sorted
 }
 
-fn handle_controllers[X](controllers []&ControllerPath, ctx Context, mut url urllib.URL, host string) ?Context {
+fn handle_controllers[X](controllers []&ControllerPath, ctx &Context, mut url urllib.URL, host string) ?&Context {
 	for controller in controllers {
 		// skip controller if the hosts don't match
 		if controller.host != '' && host != controller.host {
diff --git a/vlib/x/vweb/csrf/csrf_test.v b/vlib/x/vweb/csrf/csrf_test.v
index b5ec1ec7f6..fb23dbe440 100644
--- a/vlib/x/vweb/csrf/csrf_test.v
+++ b/vlib/x/vweb/csrf/csrf_test.v
@@ -187,6 +187,12 @@ pub struct Context {
 
 pub struct App {
 	vweb.Middleware[Context]
+mut:
+	started chan bool
+}
+
+pub fn (mut app App) before_accept_loop() {
+	app.started <- true
 }
 
 fn (app &App) index(mut ctx Context) vweb.Result {
@@ -234,10 +240,9 @@ fn test_run_app_in_background() {
 	mut app := &App{}
 	app.route_use('/auth', csrf.middleware[Context](csrf_config))
 
-	spawn vweb.run_at[App, Context](mut app, port: sport, family: .ip)
 	spawn exit_after_timeout(mut app, exit_after_time)
-
-	time.sleep(500 * time.millisecond)
+	spawn vweb.run_at[App, Context](mut app, port: sport, family: .ip)
+	_ := <-app.started
 }
 
 fn test_token_input() {
diff --git a/vlib/x/vweb/sendfile_linux.c.v b/vlib/x/vweb/sendfile_linux.c.v
new file mode 100644
index 0000000000..22508bead0
--- /dev/null
+++ b/vlib/x/vweb/sendfile_linux.c.v
@@ -0,0 +1,8 @@
+module vweb
+
+fn C.sendfile(out_fd int, in_fd int, offset voidptr, count int) int
+
+fn sendfile(out_fd int, in_fd int, nr_bytes int) int {
+	// always pass nil as offset, so the file offset will be used and updated.
+	return C.sendfile(out_fd, in_fd, 0, nr_bytes)
+}
diff --git a/vlib/x/vweb/sse/sse_test.v b/vlib/x/vweb/sse/sse_test.v
index 6e14af6b58..cc56d0dbf4 100644
--- a/vlib/x/vweb/sse/sse_test.v
+++ b/vlib/x/vweb/sse/sse_test.v
@@ -12,7 +12,14 @@ pub struct Context {
 	vweb.Context
 }
 
-pub struct App {}
+pub struct App {
+mut:
+	started chan bool
+}
+
+pub fn (mut app App) before_accept_loop() {
+	app.started <- true
+}
 
 fn (app &App) sse(mut ctx Context) vweb.Result {
 	ctx.takeover_conn()
@@ -32,15 +39,15 @@ fn handle_sse_conn(mut ctx Context) {
 
 fn testsuite_begin() {
 	mut app := &App{}
-
-	spawn vweb.run_at[App, Context](mut app, port: port, family: .ip)
-	// app startup time
-	time.sleep(time.second * 2)
 	spawn fn () {
 		time.sleep(exit_after)
 		assert true == false, 'timeout reached!'
 		exit(1)
 	}()
+
+	spawn vweb.run_at[App, Context](mut app, port: port, family: .ip)
+	// app startup time
+	_ := <-app.started
 }
 
 fn test_sse() ! {
diff --git a/vlib/x/vweb/tests/controller_test.v b/vlib/x/vweb/tests/controller_test.v
index cbb19bbfc9..a0736ff336 100644
--- a/vlib/x/vweb/tests/controller_test.v
+++ b/vlib/x/vweb/tests/controller_test.v
@@ -15,6 +15,12 @@ pub struct Context {
 
 pub struct App {
 	vweb.Controller
+mut:
+	started chan bool
+}
+
+pub fn (mut app App) before_accept_loop() {
+	app.started <- true
 }
 
 pub fn (app &App) index(mut ctx Context) vweb.Result {
@@ -49,24 +55,19 @@ pub fn (app &SubController) index(mut ctx Context) vweb.Result {
 fn testsuite_begin() {
 	os.chdir(os.dir(@FILE))!
 
-	spawn fn () ! {
-		mut sub := &SubController{}
-		mut other := &Other{}
-		other.register_controller[SubController, Context]('/sub', mut sub)!
-		mut hidden := &HiddenByOther{}
+	mut sub := &SubController{}
+	mut other := &Other{}
+	other.register_controller[SubController, Context]('/sub', mut sub)!
+	mut hidden := &HiddenByOther{}
 
-		mut app := &App{}
-		app.register_controller[Other, Context]('/other', mut other)!
-		// controllers should be sorted, so this controller should be accessible
-		// even though it is declared last
-		app.register_controller[HiddenByOther, Context]('/other/hide', mut hidden)!
+	mut app := &App{}
+	app.register_controller[Other, Context]('/other', mut other)!
+	// controllers should be sorted, so this controller should be accessible
+	// even though it is declared last
+	app.register_controller[HiddenByOther, Context]('/other/hide', mut hidden)!
 
-		vweb.run_at[App, Context](mut app, port: port, timeout_in_seconds: 2, family: .ip) or {
-			panic('could not start vweb app')
-		}
-	}()
-	// app startup time
-	time.sleep(time.second * 10)
+	spawn vweb.run_at[App, Context](mut app, port: port, timeout_in_seconds: 2, family: .ip)
+	_ := <-app.started
 
 	spawn fn () {
 		time.sleep(exit_after)
diff --git a/vlib/x/vweb/tests/large_payload_test.v b/vlib/x/vweb/tests/large_payload_test.v
index e95cfefaad..8989b3cada 100644
--- a/vlib/x/vweb/tests/large_payload_test.v
+++ b/vlib/x/vweb/tests/large_payload_test.v
@@ -13,7 +13,14 @@ const exit_after = time.second * 10
 
 const tmp_file = os.join_path(os.vtmp_dir(), 'vweb_large_payload.txt')
 
-pub struct App {}
+pub struct App {
+mut:
+	started chan bool
+}
+
+pub fn (mut app App) before_accept_loop() {
+	app.started <- true
+}
 
 pub fn (mut app App) index(mut ctx Context) vweb.Result {
 	return ctx.text('Hello V!')
@@ -33,21 +40,16 @@ pub struct Context {
 }
 
 fn testsuite_begin() {
-	spawn fn () {
-		mut app := &App{}
-		vweb.run_at[App, Context](mut app, port: port, timeout_in_seconds: 2, family: .ip) or {
-			panic('could not start vweb app')
-		}
-	}()
-
-	// app startup time
-	time.sleep(time.millisecond * 500)
-
 	spawn fn () {
 		time.sleep(exit_after)
 		assert true == false, 'timeout reached!'
 		exit(1)
 	}()
+
+	mut app := &App{}
+	spawn vweb.run_at[App, Context](mut app, port: port, timeout_in_seconds: 2, family: .ip)
+	// app startup time
+	_ := <-app.started
 }
 
 fn test_large_request_body() {
diff --git a/vlib/x/vweb/tests/middleware_test.v b/vlib/x/vweb/tests/middleware_test.v
index c1f954af5e..6fc97e398f 100644
--- a/vlib/x/vweb/tests/middleware_test.v
+++ b/vlib/x/vweb/tests/middleware_test.v
@@ -18,6 +18,12 @@ pub mut:
 @[heap]
 pub struct App {
 	vweb.Middleware[Context]
+mut:
+	started chan bool
+}
+
+pub fn (mut app App) before_accept_loop() {
+	app.started <- true
 }
 
 pub fn (app &App) index(mut ctx Context) vweb.Result {
@@ -66,28 +72,24 @@ fn after_middleware(mut ctx Context) bool {
 fn testsuite_begin() {
 	os.chdir(os.dir(@FILE))!
 
-	spawn fn () {
-		mut app := &App{}
-		// even though `route_use` is called first, global middleware is still executed first
-		app.Middleware.route_use('/unreachable', handler: middleware_unreachable)
+	mut app := &App{}
+	// even though `route_use` is called first, global middleware is still executed first
+	app.Middleware.route_use('/unreachable', handler: middleware_unreachable)
 
-		// global middleware
-		app.Middleware.use(handler: middleware_handler)
-		app.Middleware.use(handler: app.app_middleware)
+	// global middleware
+	app.Middleware.use(handler: middleware_handler)
+	app.Middleware.use(handler: app.app_middleware)
 
-		// should match only one slash
-		app.Middleware.route_use('/bar/:foo', handler: middleware_handler)
-		// should match multiple slashes
-		app.Middleware.route_use('/nested/:path...', handler: middleware_handler)
+	// should match only one slash
+	app.Middleware.route_use('/bar/:foo', handler: middleware_handler)
+	// should match multiple slashes
+	app.Middleware.route_use('/nested/:path...', handler: middleware_handler)
 
-		app.Middleware.route_use('/after', handler: after_middleware, after: true)
+	app.Middleware.route_use('/after', handler: after_middleware, after: true)
 
-		vweb.run_at[App, Context](mut app, port: port, timeout_in_seconds: 2, family: .ip) or {
-			panic('could not start vweb app')
-		}
-	}()
+	spawn vweb.run_at[App, Context](mut app, port: port, timeout_in_seconds: 2, family: .ip)
 	// app startup time
-	time.sleep(time.second * 2)
+	_ := <-app.started
 
 	spawn fn () {
 		time.sleep(exit_after)
diff --git a/vlib/x/vweb/tests/static_handler_test.v b/vlib/x/vweb/tests/static_handler_test.v
index 8ddc952601..31ae20ba53 100644
--- a/vlib/x/vweb/tests/static_handler_test.v
+++ b/vlib/x/vweb/tests/static_handler_test.v
@@ -11,6 +11,12 @@ const exit_after = time.second * 10
 
 pub struct App {
 	vweb.StaticHandler
+mut:
+	started chan bool
+}
+
+pub fn (mut app App) before_accept_loop() {
+	app.started <- true
 }
 
 pub fn (mut app App) index(mut ctx Context) vweb.Result {
@@ -28,16 +34,13 @@ pub struct Context {
 
 fn testsuite_begin() {
 	os.chdir(os.dir(@FILE))!
-	spawn run_app_test()
-
-	// app startup time
-	time.sleep(time.second * 2)
-
 	spawn fn () {
 		time.sleep(exit_after)
 		assert true == false, 'timeout reached!'
 		exit(1)
 	}()
+
+	run_app_test()
 }
 
 fn run_app_test() {
@@ -72,9 +75,9 @@ fn run_app_test() {
 
 	app.mount_static_folder_at('testdata', '/static') or { panic(err) }
 
-	vweb.run_at[App, Context](mut app, port: port, timeout_in_seconds: 2, family: .ip) or {
-		panic('could not start vweb app')
-	}
+	spawn vweb.run_at[App, Context](mut app, port: port, timeout_in_seconds: 2, family: .ip)
+	// app startup time
+	_ := <-app.started
 }
 
 fn test_static_root() {
diff --git a/vlib/x/vweb/tests/vweb_app_test.v b/vlib/x/vweb/tests/vweb_app_test.v
index b63e78162a..660d4a5c12 100644
--- a/vlib/x/vweb/tests/vweb_app_test.v
+++ b/vlib/x/vweb/tests/vweb_app_test.v
@@ -12,7 +12,12 @@ pub mut:
 
 pub struct App {
 pub mut:
-	db sqlite.DB
+	db      sqlite.DB
+	started chan bool
+}
+
+pub fn (mut app App) before_accept_loop() {
+	app.started <- true
 }
 
 struct Article {
@@ -27,7 +32,9 @@ fn test_a_vweb_application_compiles() {
 		exit(0)
 	}()
 	mut app := &App{}
-	vweb.run_at[App, Context](mut app, port: port, family: .ip, timeout_in_seconds: 10)!
+	spawn vweb.run_at[App, Context](mut app, port: port, family: .ip, timeout_in_seconds: 2)
+	// app startup time
+	_ := <-app.started
 }
 
 pub fn (mut ctx Context) before_request() {
diff --git a/vlib/x/vweb/tests/vweb_should_listen_on_both_ipv4_and_ipv6_by_default_test.v b/vlib/x/vweb/tests/vweb_should_listen_on_both_ipv4_and_ipv6_by_default_test.v
new file mode 100644
index 0000000000..876cb4ebba
--- /dev/null
+++ b/vlib/x/vweb/tests/vweb_should_listen_on_both_ipv4_and_ipv6_by_default_test.v
@@ -0,0 +1,123 @@
+import os
+import log
+import time
+import x.vweb
+import net.http
+
+const vexe = os.getenv('VEXE')
+const vroot = os.dir(vexe)
+const port = 28872
+const welcome_text = 'Welcome to our simple vweb server'
+
+// Use a known good http client like `curl` (if it exists):
+const curl_executable = os.find_abs_path_of_executable('curl') or { '' }
+const curl_ok = curl_supports_ipv6()
+
+fn curl_supports_ipv6() bool {
+	if curl_executable == '' {
+		return false
+	}
+	curl_res := os.execute('${curl_executable} --version')
+	if curl_res.exit_code != 0 {
+		return false
+	}
+	if !curl_res.output.match_glob('curl*Features: * IPv6 *') {
+		return false
+	}
+	return true
+}
+
+fn testsuite_begin() {
+	log.set_level(.debug)
+	log.debug(@FN)
+	os.chdir(vroot) or {}
+	if curl_ok {
+		log.info('working curl_executable found at: ${curl_executable}')
+	} else {
+		log.warn('no working working curl_executable found')
+	}
+	start_services()
+}
+
+fn testsuite_end() {
+	log.debug(@FN)
+}
+
+//
+
+fn ensure_curl_works(tname string) ? {
+	if !curl_ok {
+		log.warn('skipping test ${tname}, since it needs a working curl')
+		return none
+	}
+}
+
+fn test_curl_connecting_through_ipv4_works() {
+	ensure_curl_works(@FN) or { return }
+	res := os.execute('${curl_executable} --connect-timeout 0.5 --silent http://127.0.0.1:${port}/')
+	assert res.exit_code == 0, res.output
+	assert res.output == welcome_text
+	log.info('> ${@FN}')
+}
+
+fn test_net_http_connecting_through_ipv4_works() {
+	res := http.get('http://127.0.0.1:${port}/')!
+	assert res.status_code == 200, res.str()
+	assert res.status_msg == 'OK', res.str()
+	assert res.body == welcome_text, res.str()
+	log.info('> ${@FN}')
+}
+
+fn test_curl_connecting_through_ipv6_works() {
+	ensure_curl_works(@FN) or { return }
+	res := os.execute('${curl_executable} --silent --connect-timeout 0.5 http://[::1]:${port}/')
+	assert res.exit_code == 0, res.output
+	assert res.output == welcome_text
+	log.info('> ${@FN}')
+}
+
+fn test_net_http_connecting_through_ipv6_works() {
+	$if windows {
+		log.warn('skipping test ${@FN} on windows for now')
+		return
+	}
+	res := http.get('http://[::1]:${port}/')!
+	assert res.status_code == 200, res.str()
+	assert res.status_msg == 'OK', res.str()
+	assert res.body == welcome_text, res.str()
+	log.info('> ${@FN}')
+}
+
+//
+
+pub struct Context {
+	vweb.Context
+}
+
+pub struct App {
+mut:
+	started chan bool
+}
+
+pub fn (mut app App) before_accept_loop() {
+	app.started <- true
+}
+
+pub fn (mut app App) index(mut ctx Context) vweb.Result {
+	return ctx.text(welcome_text)
+}
+
+fn start_services() {
+	log.debug('starting watchdog thread to ensure the test will always exit one way or another...')
+	spawn fn (timeout_in_ms int) {
+		time.sleep(timeout_in_ms * time.millisecond)
+		log.error('Timeout of ${timeout_in_ms} ms reached, for webserver: pid: ${os.getpid()}. Exiting ...')
+		exit(1)
+	}(10_000)
+
+	log.debug('starting webserver...')
+	mut app := &App{}
+	spawn vweb.run[App, Context](mut app, port)
+	_ := <-app.started
+	log.debug('webserver started')
+}
diff --git a/vlib/x/vweb/tests/vweb_test.v b/vlib/x/vweb/tests/vweb_test.v
index eaac77c8c4..fec4190222 100644
--- a/vlib/x/vweb/tests/vweb_test.v
+++ b/vlib/x/vweb/tests/vweb_test.v
@@ -339,3 +339,16 @@ ${config.content}'
 	}
 	return read.bytestr()
 }
+
+// for issue 20476
+// phenomenon: parsing url error when querypath is `//`
+fn test_empty_querypath() {
+	mut x := http.get('http://${localserver}') or { panic(err) }
+	assert x.body == 'Welcome to VWeb'
+	x = http.get('http://${localserver}/') or { panic(err) }
+	assert x.body == 'Welcome to VWeb'
+	x = http.get('http://${localserver}//') or { panic(err) }
+	assert x.body == 'Welcome to VWeb'
+	x = http.get('http://${localserver}///') or { panic(err) }
+	assert x.body == 'Welcome to VWeb'
+}
diff --git a/vlib/x/vweb/vweb.v b/vlib/x/vweb/vweb.v
index fb72693151..0324cbcb36 100644
--- a/vlib/x/vweb/vweb.v
+++ b/vlib/x/vweb/vweb.v
@@ -187,16 +187,18 @@ fn generate_routes[A, X](app &A) !map[string]Route {
 				return error('error parsing method attributes: ${err}')
 			}
 
-			routes[method.name] = Route{
+			mut route := Route{
 				methods: http_methods
 				path: route_path
 				host: host
 			}
 
 			$if A is MiddlewareApp {
-				routes[method.name].middlewares = app.Middleware.get_handlers_for_route[X](route_path)
-				routes[method.name].after_middlewares = app.Middleware.get_handlers_for_route_after[X](route_path)
+				route.middlewares = app.Middleware.get_handlers_for_route[X](route_path)
+				route.after_middlewares = app.Middleware.get_handlers_for_route_after[X](route_path)
 			}
+
+			routes[method.name] = route
 		}
 	}
 	return routes
@@ -272,6 +274,11 @@ pub fn (mut params RequestParams) request_done(fd int) {
 	params.idx[fd] = 0
 }
 
+interface BeforeAcceptApp {
+mut:
+	before_accept_loop()
+}
+
 // run_at - start a new VWeb server, listening only on a specific address `host`, at the specified `port`
 // Example: vweb.run_at(new_app(), vweb.RunParams{ host: 'localhost' port: 8099 family: .ip }) or { panic(err) }
 @[direct_array_access; manualfree]
@@ -284,7 +291,8 @@ pub fn run_at[A, X](mut global_app A, params RunParams) ! {
 	controllers_sorted := check_duplicate_routes_in_controllers[A](global_app, routes)!
 
 	if params.show_startup_message {
-		println('[Vweb] Running app on http://localhost:${params.port}/')
+		host := if params.host == '' { 'localhost' } else { params.host }
+		println('[Vweb] Running app on http://${host}:${params.port}/')
 	}
 	flush_stdout()
 
@@ -312,7 +320,11 @@ pub fn run_at[A, X](mut global_app A, params RunParams) ! {
 		timeout_secs: params.timeout_in_seconds
 		family: params.family
 		host: params.host
-	)
+	)!
+
+	$if A is BeforeAcceptApp {
+		global_app.before_accept_loop()
+	}
 
 	// Forever accept every connection that comes
 	pico.serve()
@@ -371,32 +383,38 @@ fn handle_timeout(mut pv picoev.Picoev, mut params RequestParams, fd int) {
 fn handle_write_file(mut pv picoev.Picoev, mut params RequestParams, fd int) {
 	mut bytes_to_write := int(params.file_responses[fd].total - params.file_responses[fd].pos)
 
-	if bytes_to_write > vweb.max_write {
-		bytes_to_write = vweb.max_write
-	}
-	data := unsafe { malloc(bytes_to_write) }
-	defer {
-		unsafe { free(data) }
+	$if linux {
+		bytes_written := sendfile(fd, params.file_responses[fd].file.fd, bytes_to_write)
+		params.file_responses[fd].pos += bytes_written
+	} $else {
+		if bytes_to_write > vweb.max_write {
+			bytes_to_write = vweb.max_write
+		}
+
+		data := unsafe { malloc(bytes_to_write) }
+		defer {
+			unsafe { free(data) }
+		}
+
+		mut conn := &net.TcpConn{
+			sock: net.tcp_socket_from_handle_raw(fd)
+			handle: fd
+			is_blocking: false
+		}
+
+		params.file_responses[fd].file.read_into_ptr(data, bytes_to_write) or {
+			params.file_responses[fd].done()
+			pv.close_conn(fd)
+			return
+		}
+		actual_written := send_string_ptr(mut conn, data, bytes_to_write) or {
+			params.file_responses[fd].done()
+			pv.close_conn(fd)
+			return
+		}
+		params.file_responses[fd].pos += actual_written
 	}
 
-	mut conn := &net.TcpConn{
-		sock: net.tcp_socket_from_handle_raw(fd)
-		handle: fd
-		is_blocking: false
-	}
-
-	// TODO: use `sendfile` in linux for optimizations (?)
-	params.file_responses[fd].file.read_into_ptr(data, bytes_to_write) or {
-		params.file_responses[fd].done()
-		pv.close_conn(fd)
-		return
-	}
-	actual_written := send_string_ptr(mut conn, data, bytes_to_write) or {
-		params.file_responses[fd].done()
-		pv.close_conn(fd)
-		return
-	}
-	params.file_responses[fd].pos += actual_written
 	if params.file_responses[fd].pos == params.file_responses[fd].total {
 		// file is done writing
 		params.file_responses[fd].done()
@@ -622,7 +640,7 @@ fn handle_read[A, X](mut pv picoev.Picoev, mut params RequestParams, fd int) {
 	}
 }
 
-fn handle_request[A, X](mut conn net.TcpConn, req http.Request, params &RequestParams) ?Context {
+fn handle_request[A, X](mut conn net.TcpConn, req http.Request, params &RequestParams) ?&Context {
 	mut global_app := unsafe { &A(params.global_app) }
 
 	// TODO: change this variable to include the total wait time over each network cycle
@@ -654,7 +672,7 @@ fn handle_request[A, X](mut conn net.TcpConn, req http.Request, params &RequestP
 	host, _ := urllib.split_host_port(host_with_port)
 
 	// Create Context with request data
-	mut ctx := Context{
+	mut ctx := &Context{
 		req: req
 		page_gen_start: page_gen_start
 		conn: conn
@@ -681,8 +699,8 @@ fn handle_request[A, X](mut conn net.TcpConn, req http.Request, params &RequestP
 	user_context.Context = ctx
 
 	handle_route[A, X](mut global_app, mut user_context, url, host, params.routes)
-
-	return user_context.Context
+	// we need to explicitly tell the V compiler to return a reference
+	return &user_context.Context
 }
 
 fn handle_route[A, X](mut app A, mut user_context X, url urllib.URL, host string, routes &map[string]Route) {