diff --git a/dune-project b/dune-project
index bdbc7c57b..337b6c1e3 100644
--- a/dune-project
+++ b/dune-project
@@ -28,6 +28,7 @@ The client-side code is compiled to JS using Ocsigen Js_of_ocaml or to Wasm usin
   ppx_deriving
   (ppxlib (>= 0.15))
   (js_of_ocaml-compiler (>= 6.0))
+  wasm_of_ocaml-compiler
   (js_of_ocaml (>= 6.0))
   (js_of_ocaml-lwt (>= 6.0))
   (js_of_ocaml-ocamlbuild :build)
diff --git a/eliom.opam b/eliom.opam
index 0a5a47907..02b69bbbe 100644
--- a/eliom.opam
+++ b/eliom.opam
@@ -23,6 +23,7 @@ depends: [
   "ppx_deriving"
   "ppxlib" {>= "0.15"}
   "js_of_ocaml-compiler" {>= "6.0"}
+  "wasm_of_ocaml-compiler"
   "js_of_ocaml" {>= "6.0"}
   "js_of_ocaml-lwt" {>= "6.0"}
   "js_of_ocaml-ocamlbuild" {build}
diff --git a/pkg/distillery/templates/app.exe/Makefile.app b/pkg/distillery/templates/app.exe/Makefile.app
index a26f95f10..5ad648b8c 100644
--- a/pkg/distillery/templates/app.exe/Makefile.app
+++ b/pkg/distillery/templates/app.exe/Makefile.app
@@ -67,6 +67,15 @@ install.static: $(TEST_PREFIX)$(ELIOMSTATICDIR)/$(PROJECT_NAME).js | $(PREFIX)$(
 	HASH=`md5sum _build/default/client/$(PROJECT_NAME).bc.js | cut -d ' ' -f 1` && \
 	install $(addprefix -o ,$(WWWUSER)) $(JS_PREFIX)_$$HASH.js $(PREFIX)$(ELIOMSTATICDIR) && \
 	ln -sf $(PROJECT_NAME)_$$HASH.js $(PREFIX)$(ELIOMSTATICDIR)/$(PROJECT_NAME).js
+ifeq ($(ENABLE_WASM),yes)
+	HASH_WASM=`md5sum _build/default/client/$(PROJECT_NAME).bc.wasm.js | cut -d ' ' -f 1` && \
+	install $(addprefix -o ,$(WWWUSER)) $(JS_PREFIX)_$$HASH_WASM.wasm.js $(PREFIX)$(ELIOMSTATICDIR) && \
+	ln -sf $(PROJECT_NAME)_$$HASH_WASM.wasm.js $(PREFIX)$(ELIOMSTATICDIR)/$(PROJECT_NAME).wasm.js
+	if [ -d _build/default/client/$(PROJECT_NAME).bc.wasm.assets ]; then \
+	  cp -rf _build/default/client/$(PROJECT_NAME).bc.wasm.assets $(PREFIX)$(ELIOMSTATICDIR)/; \
+	  [ -z $(WWWUSER) ] || chown -R $(WWWUSER) $(PREFIX)$(ELIOMSTATICDIR)/$(PROJECT_NAME).bc.wasm.assets; \
+	fi
+endif
 	[ -z $(WWWUSER) ] || chown -R $(WWWUSER) $(PREFIX)$(FILESDIR)
 
 .PHONY:
@@ -91,6 +100,14 @@ config-files: | $(TEST_PREFIX)$(ELIOMSTATICDIR) $(TEST_PREFIX)$(LIBDIR)
 	HASH=`md5sum _build/default/client/$(PROJECT_NAME).bc.js | cut -d ' ' -f 1` && \
 	cp -f _build/default/client/$(PROJECT_NAME).bc.js $(JS_PREFIX)_$$HASH.js && \
 	ln -sf $(PROJECT_NAME)_$$HASH.js $(JS_PREFIX).js
+ifeq ($(ENABLE_WASM),yes)
+	HASH_WASM=`md5sum _build/default/client/$(PROJECT_NAME).bc.wasm.js | cut -d ' ' -f 1` && \
+	cp -f _build/default/client/$(PROJECT_NAME).bc.wasm.js $(JS_PREFIX)_$$HASH_WASM.wasm.js && \
+	ln -sf $(PROJECT_NAME)_$$HASH_WASM.wasm.js $(JS_PREFIX).wasm.js
+	if [ -d _build/default/client/$(PROJECT_NAME).bc.wasm.assets ]; then \
+	  cp -rf _build/default/client/$(PROJECT_NAME).bc.wasm.assets $(TEST_PREFIX)$(ELIOMSTATICDIR)/; \
+	fi
+endif
 	cp -f _build/default/$(PROJECT_NAME).cm* $(TEST_PREFIX)$(LIBDIR)/
 
 all::
@@ -98,6 +115,9 @@ all::
 
 js::
 	$(ENV_PSQL) dune build $(DUNE_OPTIONS) client/$(PROJECT_NAME).bc.js
+ifeq ($(ENABLE_WASM),yes)
+	$(ENV_PSQL) dune build $(DUNE_OPTIONS) client/$(PROJECT_NAME).bc.wasm.js
+endif
 
 byte:: js
 	$(ENV_PSQL) dune build $(DUNE_OPTIONS) $(PROJECT_NAME)_main.bc
diff --git a/pkg/distillery/templates/app.exe/Makefile.options b/pkg/distillery/templates/app.exe/Makefile.options
index 6e6550394..2496462f1 100644
--- a/pkg/distillery/templates/app.exe/Makefile.options
+++ b/pkg/distillery/templates/app.exe/Makefile.options
@@ -73,5 +73,8 @@ CSS_PREFIX            := $(LOCAL_STATIC_CSS)/${PROJECT_NAME}
 # JavaScript, ocsigenserver
 DEBUG                 := yes
 
+# Enable WASM compilation (yes/no): Requires wasm_of_ocaml (enabled by default)
+ENABLE_WASM           := yes
+
 ##----------------------------------------------------------------------
 
diff --git a/pkg/distillery/templates/app.exe/PROJECT_NAME.eliom b/pkg/distillery/templates/app.exe/PROJECT_NAME.eliom
index 2f69b1386..d09e9404f 100644
--- a/pkg/distillery/templates/app.exe/PROJECT_NAME.eliom
+++ b/pkg/distillery/templates/app.exe/PROJECT_NAME.eliom
@@ -5,7 +5,11 @@ let%server application_name = "%%%PROJECT_NAME%%%"
 let%client application_name = Eliom_client.get_application_name ()
 
 let%server () =
-    Ocsipersist_settings.set_db_file "local/var/data/%%%PROJECT_NAME%%%/%%%PROJECT_NAME%%%_db";
+    Ocsipersist_settings.set_db_file "local/var/data/%%%PROJECT_NAME%%%/%%%PROJECT_NAME%%%_db"
+    (* Enable WebAssembly support with automatic browser detection.
+       The server will load the WASM version if the browser supports it,
+       with fallback to JavaScript otherwise. *)
+    ; Eliom_config.set_enable_wasm true
 
 (* Create a module for the application. See
    https://ocsigen.org/eliom/manual/clientserver-applications for more
diff --git a/pkg/distillery/templates/app.exe/dune b/pkg/distillery/templates/app.exe/dune
index 79f6fd711..30daabc8a 100644
--- a/pkg/distillery/templates/app.exe/dune
+++ b/pkg/distillery/templates/app.exe/dune
@@ -86,7 +86,7 @@
  client
  (executables
   (names %%%PROJECT_NAME%%%)
-  (modes js byte)
+  (modes js byte wasm)
   (preprocess
    (pps
     js_of_ocaml-ppx
@@ -106,9 +106,9 @@
     --enable
     with-js-error
     --enable
-    use-js-string
-    --no-source-map))
-  ; source maps are slow...
+    use-js-string))
+  (wasm_of_ocaml
+   (flags :standard))
   (libraries eliom.client))
  (dynamic_include ../gen/dune.client))
 
@@ -122,6 +122,7 @@
   %%%PROJECT_NAME%%%_main.exe
   client/%%%PROJECT_NAME%%%.bc
   client/%%%PROJECT_NAME%%%.bc.js
+  client/%%%PROJECT_NAME%%%.bc.wasm.js
   tools/check_modules.ml)
  (action
   (run ocaml -I +unix -I +str tools/check_modules.ml %%%PROJECT_NAME%%%)))
diff --git a/pkg/distillery/templates/app.exe/dune-project b/pkg/distillery/templates/app.exe/dune-project
index ba1d67e4a..cf94fbb75 100644
--- a/pkg/distillery/templates/app.exe/dune-project
+++ b/pkg/distillery/templates/app.exe/dune-project
@@ -1,10 +1,13 @@
-(lang dune 3.14)
+(lang dune 3.17)
 
 (dialect
  (name "eliom-server")
- (implementation (extension "eliom"))
- (interface (extension "eliomi")))
+ (implementation
+  (extension "eliom"))
+ (interface
+  (extension "eliomi")))
 
 (wrapped_executables false)
 
-(formatting (enabled_for ocaml "eliom-server"))
+(formatting
+ (enabled_for ocaml "eliom-server"))
diff --git a/pkg/distillery/templates/app.lib/Makefile.app b/pkg/distillery/templates/app.lib/Makefile.app
index fbcf2ab9e..660e0e8c5 100644
--- a/pkg/distillery/templates/app.lib/Makefile.app
+++ b/pkg/distillery/templates/app.lib/Makefile.app
@@ -74,6 +74,15 @@ install.static: $(TEST_PREFIX)$(ELIOMSTATICDIR)/$(PROJECT_NAME).js | $(PREFIX)$(
 	HASH=`md5sum _build/default/client/$(PROJECT_NAME).bc.js | cut -d ' ' -f 1` && \
 	install $(addprefix -o ,$(WWWUSER)) $(JS_PREFIX)_$$HASH.js $(PREFIX)$(ELIOMSTATICDIR) && \
 	ln -sf $(PROJECT_NAME)_$$HASH.js $(PREFIX)$(ELIOMSTATICDIR)/$(PROJECT_NAME).js
+ifeq ($(ENABLE_WASM),yes)
+	HASH_WASM=`md5sum _build/default/client/$(PROJECT_NAME).bc.wasm.js | cut -d ' ' -f 1` && \
+	install $(addprefix -o ,$(WWWUSER)) $(JS_PREFIX)_$$HASH_WASM.wasm.js $(PREFIX)$(ELIOMSTATICDIR) && \
+	ln -sf $(PROJECT_NAME)_$$HASH_WASM.wasm.js $(PREFIX)$(ELIOMSTATICDIR)/$(PROJECT_NAME).wasm.js
+	if [ -d _build/default/client/$(PROJECT_NAME).bc.wasm.assets ]; then \
+	  cp -rf _build/default/client/$(PROJECT_NAME).bc.wasm.assets $(PREFIX)$(ELIOMSTATICDIR)/; \
+	  [ -z $(WWWUSER) ] || chown -R $(WWWUSER) $(PREFIX)$(ELIOMSTATICDIR)/$(PROJECT_NAME).bc.wasm.assets; \
+	fi
+endif
 	[ -z $(WWWUSER) ] || chown -R $(WWWUSER) $(PREFIX)$(FILESDIR)
 install.etc: $(TEST_PREFIX)$(ETCDIR)/$(PROJECT_NAME).conf | $(PREFIX)$(ETCDIR)
 	install $< $(PREFIX)$(ETCDIR)/$(PROJECT_NAME).conf
@@ -122,6 +131,11 @@ SED_ARGS += -e "s|%%FILESDIR%%|%%PREFIX%%$(FILESDIR)|g"
 SED_ARGS += -e "s|%%ELIOMSTATICDIR%%|%%PREFIX%%$(ELIOMSTATICDIR)|g"
 SED_ARGS += -e "s|%%APPNAME%%|$(shell basename `readlink $(JS_PREFIX).js` .js)|g"
 SED_ARGS += -e "s|%%CSSNAME%%|$(shell readlink $(CSS_PREFIX).css)|g"
+ifeq ($(ENABLE_WASM),yes)
+  SED_ARGS += -e "s|%%WASMATTR%%|wasm=\"$(shell basename `readlink $(JS_PREFIX).wasm.js` .wasm.js).wasm.js\"|g"
+else
+  SED_ARGS += -e "s|%%WASMATTR%%||g"
+endif
 ifeq ($(DEBUG),yes)
   SED_ARGS += -e "s|%%DEBUGMODE%%|\<debugmode /\>|g"
 else
@@ -156,6 +170,14 @@ config-files: | $(TEST_PREFIX)$(ELIOMSTATICDIR) $(TEST_PREFIX)$(LIBDIR)
 	HASH=`md5sum _build/default/client/$(PROJECT_NAME).bc.js | cut -d ' ' -f 1` && \
 	cp -f _build/default/client/$(PROJECT_NAME).bc.js $(JS_PREFIX)_$$HASH.js && \
 	ln -sf $(PROJECT_NAME)_$$HASH.js $(JS_PREFIX).js
+ifeq ($(ENABLE_WASM),yes)
+	HASH_WASM=`md5sum _build/default/client/$(PROJECT_NAME).bc.wasm.js | cut -d ' ' -f 1` && \
+	cp -f _build/default/client/$(PROJECT_NAME).bc.wasm.js $(JS_PREFIX)_$$HASH_WASM.wasm.js && \
+	ln -sf $(PROJECT_NAME)_$$HASH_WASM.wasm.js $(JS_PREFIX).wasm.js
+	if [ -d _build/default/client/$(PROJECT_NAME).bc.wasm.assets ]; then \
+	  cp -rf _build/default/client/$(PROJECT_NAME).bc.wasm.assets $(TEST_PREFIX)$(ELIOMSTATICDIR)/; \
+	fi
+endif
 	cp -f _build/default/$(PROJECT_NAME).cm* $(TEST_PREFIX)$(LIBDIR)/
 	$(MAKE) $(CONFIG_FILES) $(TEST_CONFIG_FILES) PROJECT_NAME=$(PROJECT_NAME)
 
@@ -164,6 +186,9 @@ all::
 
 js::
 	$(ENV_PSQL) dune build $(DUNE_OPTIONS) client/$(PROJECT_NAME).bc.js
+ifeq ($(ENABLE_WASM),yes)
+	$(ENV_PSQL) dune build $(DUNE_OPTIONS) client/$(PROJECT_NAME).bc.wasm.js
+endif
 
 byte::
 	$(ENV_PSQL) dune build $(DUNE_OPTIONS) @$(PROJECT_NAME)
diff --git a/pkg/distillery/templates/app.lib/Makefile.options b/pkg/distillery/templates/app.lib/Makefile.options
index a65be2a0e..13d2a8e8b 100644
--- a/pkg/distillery/templates/app.lib/Makefile.options
+++ b/pkg/distillery/templates/app.lib/Makefile.options
@@ -73,5 +73,8 @@ CSS_PREFIX            := $(LOCAL_STATIC_CSS)/${PROJECT_NAME}
 # JavaScript, ocsigenserver
 DEBUG                 := yes
 
+# Enable WASM compilation (yes/no): Requires wasm_of_ocaml (enabled by default)
+ENABLE_WASM           := yes
+
 ##----------------------------------------------------------------------
 
diff --git a/pkg/distillery/templates/app.lib/PROJECT_NAME.conf.in b/pkg/distillery/templates/app.lib/PROJECT_NAME.conf.in
index 0f7b3af57..bc04fa06c 100644
--- a/pkg/distillery/templates/app.lib/PROJECT_NAME.conf.in
+++ b/pkg/distillery/templates/app.lib/PROJECT_NAME.conf.in
@@ -41,6 +41,8 @@
     <extension findlib-package="eliom.server">
       <!-- Ask Eliom to ignore UTM parameters and others: -->
       <ignoredgetparams regexp="utm_[a-z]*|[a-z]*clid|li_fat_id"/>
+      <!-- Enable WebAssembly support with automatic browser detection: -->
+      <wasm enabled="true"/>
 <!-- Uncomment if you are using https only and want secure cookies:
        <securecookies value="true" />
   -->
@@ -51,7 +53,7 @@
       <static dir="%%FILESDIR%%" />
       %%ELIOM_MODULES%%
       <eliommodule module="%%LIBDIR%%/%%PROJECT_NAME%%.cma">
-        <app name="%%APPNAME%%" css="%%CSSNAME%%" />
+        <app name="%%APPNAME%%" css="%%CSSNAME%%" %%WASMATTR%% />
         <avatars dir="%%FILESDIR%%/avatars" />
         <os-db
           host="%%DB_HOST%%"
diff --git a/pkg/distillery/templates/app.lib/dune b/pkg/distillery/templates/app.lib/dune
index 3e04eda1d..18daaff65 100644
--- a/pkg/distillery/templates/app.lib/dune
+++ b/pkg/distillery/templates/app.lib/dune
@@ -57,7 +57,7 @@
  client
  (executables
   (names %%%PROJECT_NAME%%%)
-  (modes js byte)
+  (modes js byte wasm)
   (preprocess
    (pps
     js_of_ocaml-ppx
@@ -77,9 +77,9 @@
     --enable
     with-js-error
     --enable
-    use-js-string
-    --no-source-map))
-  ; source maps are slow...
+    use-js-string))
+  (wasm_of_ocaml
+   (flags :standard))
   (libraries eliom.client))
  (dynamic_include ../gen/dune.client))
 
@@ -91,6 +91,7 @@
   %%%PROJECT_NAME%%%.cma
   client/%%%PROJECT_NAME%%%.bc
   client/%%%PROJECT_NAME%%%.bc.js
+  client/%%%PROJECT_NAME%%%.bc.wasm.js
   tools/check_modules.ml)
  (action
   (run ocaml -I +unix -I +str tools/check_modules.ml %%%PROJECT_NAME%%%)))
diff --git a/pkg/distillery/templates/app.lib/dune-project b/pkg/distillery/templates/app.lib/dune-project
index ba1d67e4a..cf94fbb75 100644
--- a/pkg/distillery/templates/app.lib/dune-project
+++ b/pkg/distillery/templates/app.lib/dune-project
@@ -1,10 +1,13 @@
-(lang dune 3.14)
+(lang dune 3.17)
 
 (dialect
  (name "eliom-server")
- (implementation (extension "eliom"))
- (interface (extension "eliomi")))
+ (implementation
+  (extension "eliom"))
+ (interface
+  (extension "eliomi")))
 
 (wrapped_executables false)
 
-(formatting (enabled_for ocaml "eliom-server"))
+(formatting
+ (enabled_for ocaml "eliom-server"))
diff --git a/pkg/distillery/templates/basic.ppx/Makefile b/pkg/distillery/templates/basic.ppx/Makefile
index f2a33b741..64c9fb0be 100644
--- a/pkg/distillery/templates/basic.ppx/Makefile
+++ b/pkg/distillery/templates/basic.ppx/Makefile
@@ -1,4 +1,7 @@
 
+# NOTE: WASM support is only available in modern templates (app.exe, app.lib)
+# This legacy template (basic.ppx) does not support wasm_of_ocaml compilation
+#
 ##----------------------------------------------------------------------
 ## DISCLAIMER
 ##
diff --git a/src/lib/client/dune b/src/lib/client/dune
index dace84430..57282f90b 100644
--- a/src/lib/client/dune
+++ b/src/lib/client/dune
@@ -33,7 +33,9 @@
   (language c)
   (names eliom_stubs))
  (js_of_ocaml
-  (javascript_files eliom_client.js)))
+  (javascript_files eliom_client.js))
+ (wasm_of_ocaml
+  (wasm_files eliom_client.wat)))
 
 (include dune.client)
 
diff --git a/src/lib/eliom.server.ml b/src/lib/eliom.server.ml
index d6a871a98..44b317d59 100644
--- a/src/lib/eliom.server.ml
+++ b/src/lib/eliom.server.ml
@@ -16,6 +16,7 @@ let run
       ?max_anonymous_services_per_session
       ?secure_cookies
       ?application_script
+      ?enable_wasm
       ?global_data_caching
       ?html_content_type
       ?ignored_get_params
@@ -74,6 +75,9 @@ let run
     max_anonymous_services_per_session;
   Option.iter (fun v -> sitedata.secure_cookies <- v) secure_cookies;
   Option.iter (fun v -> sitedata.application_script <- v) application_script;
+  (* Always update enable_wasm: use provided value or current global default *)
+  sitedata.enable_wasm <-
+    Option.value enable_wasm ~default:!Eliommod.default_enable_wasm;
   Option.iter (fun v -> sitedata.cache_global_data <- v) global_data_caching;
   Option.iter (fun v -> sitedata.html_content_type <- Some v) html_content_type;
   Option.iter
diff --git a/src/lib/eliom.server.mli b/src/lib/eliom.server.mli
index 7d3cc9a8d..09d0144b6 100644
--- a/src/lib/eliom.server.mli
+++ b/src/lib/eliom.server.mli
@@ -32,6 +32,7 @@ val run :
   -> ?max_anonymous_services_per_session:int * bool
   -> ?secure_cookies:bool
   -> ?application_script:bool * bool
+  -> ?enable_wasm:bool
   -> ?global_data_caching:(string list * int) option
   -> ?html_content_type:string
   -> ?ignored_get_params:string * Re.re
@@ -42,4 +43,10 @@ val run :
 (** [run ?app ()] run Eliom application [app] under current site.
     Use this to build a static executable without configuration file.
     Default value of [?app] is [default_app_name].
-    Other optional values correspond to Eliom configuration for this site. *)
+    Other optional values correspond to Eliom configuration for this site.
+
+    When [?enable_wasm] is set to [true], the server will generate a detection
+    script that loads the WASM version of your client code if the browser
+    supports WebAssembly, with automatic fallback to JavaScript otherwise.
+    If not specified, the global default is used
+    (see {!Eliom_config.set_enable_wasm}), which is [false]. *)
diff --git a/src/lib/eliom_common.server.ml b/src/lib/eliom_common.server.ml
index 993e9defd..c221dcd5c 100644
--- a/src/lib/eliom_common.server.ml
+++ b/src/lib/eliom_common.server.ml
@@ -493,7 +493,8 @@ and sitedata =
   ; mutable ipv6mask : int option * bool
   ; mutable application_script : bool (* defer *) * bool
   ; (* async *)
-    mutable cache_global_data : (string list * int) option
+    mutable enable_wasm : bool
+  ; mutable cache_global_data : (string list * int) option
   ; mutable html_content_type : string option
   ; mutable ignored_get_params : (string * Re.re) list
   ; mutable ignored_post_params : (string * Re.re) list
diff --git a/src/lib/eliom_common.server.mli b/src/lib/eliom_common.server.mli
index 22d3088f3..04de1afa2 100644
--- a/src/lib/eliom_common.server.mli
+++ b/src/lib/eliom_common.server.mli
@@ -558,7 +558,8 @@ and sitedata =
   ; mutable ipv6mask : int option * bool
   ; mutable application_script : bool (* defer *) * bool
   ; (* async *)
-    mutable cache_global_data : (string list * int) option
+    mutable enable_wasm : bool
+  ; mutable cache_global_data : (string list * int) option
   ; mutable html_content_type : string option
   ; mutable ignored_get_params : (string * Re.re) list
   ; mutable ignored_post_params : (string * Re.re) list
diff --git a/src/lib/eliom_config.server.ml b/src/lib/eliom_config.server.ml
index 059de8720..a9ef09e74 100644
--- a/src/lib/eliom_config.server.ml
+++ b/src/lib/eliom_config.server.ml
@@ -76,6 +76,8 @@ let set_max_volatile_groups_per_site v =
 
 let set_secure_cookies v = Eliommod.default_secure_cookies := v
 let set_application_script v = Eliommod.default_application_script := v
+let set_enable_wasm v = Eliommod.default_enable_wasm := v
+let get_enable_wasm () = !Eliommod.default_enable_wasm
 let set_cache_global_data v = Eliommod.default_cache_global_data := v
 let set_html_content_type v = Eliommod.default_html_content_type := Some v
 
diff --git a/src/lib/eliom_config.server.mli b/src/lib/eliom_config.server.mli
index 6e5e8d995..c58712d49 100644
--- a/src/lib/eliom_config.server.mli
+++ b/src/lib/eliom_config.server.mli
@@ -86,6 +86,23 @@ val set_max_anonymous_services_per_session : int -> unit
 val set_max_volatile_groups_per_site : int -> unit
 val set_secure_cookies : bool -> unit
 val set_application_script : bool * bool -> unit
+
+val set_enable_wasm : bool -> unit
+(** Enable or disable WebAssembly support with automatic browser detection.
+    When enabled, Eliom will generate a script that detects WebAssembly
+    support in the browser and loads either the WASM version (.wasm.js) or
+    the JavaScript fallback (.js) accordingly.
+
+    Disabled by default for backward compatibility. The Eliom templates
+    enable it explicitly.
+
+    This setting can be overridden per-site using the [~enable_wasm] parameter
+    of {!Eliom.run} or the [<wasm enabled="true|false"/>] tag in the
+    configuration file. *)
+
+val get_enable_wasm : unit -> bool
+(** Get the current global setting for WebAssembly support. *)
+
 val set_cache_global_data : (Eliom_lib.Url.path * int) option -> unit
 val set_html_content_type : string -> unit
 val add_ignored_get_params : string * Re.re -> unit
diff --git a/src/lib/eliom_registration.server.ml b/src/lib/eliom_registration.server.ml
index 23ddbae65..0e67dc369 100644
--- a/src/lib/eliom_registration.server.ml
+++ b/src/lib/eliom_registration.server.ml
@@ -869,6 +869,14 @@ module type APP = sig
     -> unit
     -> [> `Script] Eliom_content.Html.elt
 
+  val wasm_detection_script :
+     ?defer:bool
+    -> ?async:bool
+    -> ?js_name:string
+    -> ?wasm_name:string
+    -> unit
+    -> [> `Script] Eliom_content.Html.elt
+
   val application_name : string
   val is_initial_request : unit -> bool
 
@@ -906,7 +914,64 @@ module App_base (App_param : Eliom_registration_sigs.APP_PARAM) = struct
   let eliom_appl_script_id : [`Script] Eliom_content.Html.Id.id =
     Eliom_content.Html.Id.new_elt_id ~global:true ()
 
-  let application_script ?defer ?async () =
+  (* Generate an inline script for detecting and loading WASM/JS *)
+  let wasm_detection_script ?defer ?async ?js_name ?wasm_name () =
+    let defer', async' =
+      (Eliom_request_info.get_sitedata ()).Eliom_common.application_script
+    in
+    let defer = match defer with Some b -> b | None -> defer' in
+    let async = match async with Some b -> b | None -> async' in
+    let defer_str = if defer then "true" else "false" in
+    let async_str = if async then "true" else "false" in
+    (* Use provided filenames with hash, or default to application_name *)
+    let js_filename =
+      match js_name with
+      | Some name -> name
+      | None -> App_param.application_name ^ ".js"
+    in
+    let wasm_filename =
+      match wasm_name with
+      | Some name -> name
+      | None -> App_param.application_name ^ ".wasm.js"
+    in
+    (* Generate full URIs for both JS and WASM versions using make_uri *)
+    let js_uri =
+      Eliom_content.Html.F.string_of_uri
+        (Eliom_content.Html.F.make_uri
+           ~service:(Eliom_service.static_dir ())
+           [js_filename])
+    in
+    let wasm_uri =
+      Eliom_content.Html.F.string_of_uri
+        (Eliom_content.Html.F.make_uri
+           ~service:(Eliom_service.static_dir ())
+           [wasm_filename])
+    in
+    let script_content =
+      Printf.sprintf
+        "(function() {\n\  var script = document.createElement('script');\n\  script.defer = %s;\n\  script.async = %s;\n\  \n\  if (window?.WebAssembly?.JSTag) {\n\    script.src = '%s';\n\  } else {\n\    script.src = '%s';\n\  }\n\  \n\  document.head.appendChild(script);\n})();"
+        defer_str async_str wasm_uri js_uri
+    in
+    Eliom_content.Html.Id.create_named_elt ~id:eliom_appl_script_id
+      (Eliom_content.Html.F.script
+         (Eliom_content.Html.F.cdata_script script_content))
+
+  let wasm_detection_script =
+    (wasm_detection_script
+      : ?defer:_
+        -> ?async:_
+        -> ?js_name:_
+        -> ?wasm_name:_
+        -> _
+        -> [`Script] Eliom_content.Html.elt
+      :> ?defer:_
+         -> ?async:_
+         -> ?js_name:_
+         -> ?wasm_name:_
+         -> _
+         -> [> `Script] Eliom_content.Html.elt)
+
+  let js_only_application_script ?defer ?async () =
     let defer', async' =
       (Eliom_request_info.get_sitedata ()).Eliom_common.application_script
     in
@@ -919,11 +984,17 @@ module App_base (App_param : Eliom_registration_sigs.APP_PARAM) = struct
     Eliom_content.Html.Id.create_named_elt ~id:eliom_appl_script_id
       (Eliom_content.Html.D.js_script ~a
          ~uri:
-           (Eliom_content.Html.D.make_uri
+           (Eliom_content.Html.F.make_uri
               ~service:(Eliom_service.static_dir ())
               [App_param.application_name ^ ".js"])
          ())
 
+  (* Automatically return WASM detection script or JS-only script based on config *)
+  let application_script ?defer ?async () =
+    if (Eliom_request_info.get_sitedata ()).Eliom_common.enable_wasm
+    then wasm_detection_script ?defer ?async ()
+    else js_only_application_script ?defer ?async ()
+
   let application_script =
     (application_script
       : ?defer:_ -> ?async:_ -> _ -> [`Script] Eliom_content.Html.elt
@@ -1070,7 +1141,9 @@ module App_base (App_param : Eliom_registration_sigs.APP_PARAM) = struct
     let head_elts =
       if List.exists is_eliom_appl_script head_elts
       then head_elts
-      else head_elts @ [application_script ()]
+      else
+        (* application_script now automatically detects WASM *)
+        head_elts @ [application_script ()]
     in
     let head_elts =
       appl_data_script
@@ -1181,6 +1254,7 @@ module App (App_param : Eliom_registration_sigs.APP_PARAM) = struct
 
   let is_initial_request = Base.is_initial_request
   let application_script = Base.application_script
+  let wasm_detection_script = Base.wasm_detection_script
 
   include Eliom_mkreg.Make (Base)
 
diff --git a/src/lib/eliom_registration.server.mli b/src/lib/eliom_registration.server.mli
index 4fb0feb39..1e2f109fc 100644
--- a/src/lib/eliom_registration.server.mli
+++ b/src/lib/eliom_registration.server.mli
@@ -120,6 +120,43 @@ module type APP = sig
       do not include this script in the [<head>] node of your page, it
       will be automatically added at the end of the [<head>] node. *)
 
+  val wasm_detection_script :
+     ?defer:bool
+    -> ?async:bool
+    -> ?js_name:string
+    -> ?wasm_name:string
+    -> unit
+    -> [> `Script] Eliom_content.Html.elt
+  (** The function [wasm_detection_script ()] returns an inline [<script>] node
+      that automatically detects WebAssembly support in the browser and
+      dynamically loads the appropriate version of the application.
+
+      When the browser supports WebAssembly ([typeof WebAssembly === 'object']),
+      it loads the WASM version ([.wasm.js]). Otherwise, it falls back to the
+      JavaScript version ([.js]).
+
+      This function is automatically used by Eliom when WebAssembly support is
+      enabled (see {!Eliom_config.set_enable_wasm}). The generated script
+      creates a [<script>] element dynamically with the appropriate [src]
+      attribute and appends it to the document head.
+
+      @param defer If [true], sets the [defer] attribute on the dynamically
+                   created script tag. Default comes from the site's
+                   [application_script] configuration.
+      @param async If [true], sets the [async] attribute on the dynamically
+                   created script tag. Default comes from the site's
+                   [application_script] configuration.
+      @param js_name Optional filename for the JavaScript fallback version.
+                     Useful for specifying cache-busting hashed filenames.
+                     Default is [application_name ^ ".js"].
+      @param wasm_name Optional filename for the WebAssembly version.
+                       Useful for specifying cache-busting hashed filenames.
+                       Default is [application_name ^ ".wasm.js"].
+
+      {e Warning: Like {!application_script}, do not manually include this
+      script in the [<head>] node of your page when using Eliom's automatic
+      script injection.} *)
+
   val application_name : string
   (** Unique identifier for this application. Currently, it is just
       the application name as defined by
diff --git a/src/lib/server/eliommod.ml b/src/lib/server/eliommod.ml
index 3a8fed3ad..e56583f66 100644
--- a/src/lib/server/eliommod.ml
+++ b/src/lib/server/eliommod.ml
@@ -44,6 +44,7 @@ let default_max_service_tab_sessions_per_group = ref 50
 let default_max_volatile_data_tab_sessions_per_group = ref 50
 let default_secure_cookies = ref false
 let default_application_script = ref (false, false)
+let default_enable_wasm = ref false
 let default_cache_global_data = ref None
 let default_html_content_type = ref None
 let default_ignored_get_params = ref []
@@ -144,6 +145,7 @@ let create_sitedata_aux site_dir config_info =
     ; ipv4mask = None, false
     ; ipv6mask = None, false
     ; application_script = !default_application_script
+    ; enable_wasm = !default_enable_wasm
     ; cache_global_data = !default_cache_global_data
     ; html_content_type = !default_html_content_type
     ; ignored_get_params = !default_ignored_get_params
@@ -222,6 +224,7 @@ let parse_eliom_option
       , set_ipv4mask
       , set_ipv6mask
       , set_application_script
+      , set_enable_wasm
       , set_global_data_caching
       , set_html_content_type
       , set_ignored_get_params
@@ -476,6 +479,12 @@ let parse_eliom_option
            "Eliom: Wrong attribute value for ipv6subnetmask tag"))
   | Xml.Element ("applicationscript", attrs, []) ->
       set_application_script (parse_application_script_attrs attrs)
+  | Xml.Element ("wasm", [("enabled", v)], []) -> (
+    try
+      let b = bool_of_string v in
+      set_enable_wasm b
+    with Invalid_argument _ ->
+      raise (Error_in_config_file "Eliom: Wrong attribute value for wasm tag"))
   | Xml.Element ("cacheglobaldata", attrs, []) ->
       set_global_data_caching (parse_global_data_caching_attrs attrs)
   | Xml.Element ("htmlcontenttype", [("value", v)], []) ->
@@ -592,6 +601,7 @@ let rec parse_global_config = function
         , (fun v -> Eliom_common.ipv4mask := v)
         , (fun v -> Eliom_common.ipv6mask := v)
         , (fun v -> default_application_script := v)
+        , (fun v -> default_enable_wasm := v)
         , (fun v -> default_cache_global_data := v)
         , (fun v -> default_html_content_type := Some v)
         , (fun regexp ->
@@ -942,6 +952,7 @@ let parse_config _ hostpattern conf_info site_dir =
             , (fun v -> sitedata.Eliom_common.ipv4mask <- Some v, true)
             , (fun v -> sitedata.Eliom_common.ipv6mask <- Some v, true)
             , (fun v -> sitedata.Eliom_common.application_script <- v)
+            , (fun v -> sitedata.Eliom_common.enable_wasm <- v)
             , (fun v -> sitedata.Eliom_common.cache_global_data <- v)
             , (fun v -> sitedata.Eliom_common.html_content_type <- Some v)
             , (fun regexp ->
diff --git a/src/lib/server/eliommod.mli b/src/lib/server/eliommod.mli
index 2074431bc..303e30d05 100644
--- a/src/lib/server/eliommod.mli
+++ b/src/lib/server/eliommod.mli
@@ -8,6 +8,7 @@ val default_max_service_tab_sessions_per_group : int ref
 val default_max_volatile_data_tab_sessions_per_group : int ref
 val default_secure_cookies : bool ref
 val default_application_script : (bool * bool) ref
+val default_enable_wasm : bool ref
 val default_cache_global_data : (Eliom_lib.Url.path * int) option ref
 val default_html_content_type : string option ref
 val default_ignored_get_params : (string * Re.re) list ref
@@ -86,6 +87,7 @@ val parse_eliom_option :
    * (int -> unit)
    * (int -> unit)
    * (bool * bool -> unit)
+   * (bool -> unit)
    * ((Eliom_lib.Url.path * int) option -> unit)
    * (string -> unit)
    * (string * Re.re -> unit)
@@ -126,6 +128,7 @@ val parse_eliom_options :
    * (int -> unit)
    * (int -> unit)
    * (bool * bool -> unit)
+   * (bool -> unit)
    * ((Eliom_lib.Url.path * int) option -> unit)
    * (string -> unit)
    * (string * Re.re -> unit)